August 3, 2009 Mon (1 hour):
Met with product marketing manager for LabVIEW for ARM with National Instruments to discuss NI potential sponsoring providing development software and hardware for
the team. National Instruments agreed to provide software and loan hardware for the semester (LM3S8962 eval board and uLink2 programmer/debugger). The LabVIEW for ARM is a very powerful programming
environment because of the graphical programming, project file management with auto-linker, and engineering support from NI in the development process.
WEEK 00 SUMMARY
Accomplishments: Recieved approval for sponsorship from National Instruments with the LabVIEW for ARM development package.
Weekly Work Total: 1 hour
Project Work Total: 1 hour
August 25, 2009 Tue (1 hour):
Met as a team after class to discuss preliminary project proposal. Discussed the idea of how to make the mechanical portion of a motorized
golf bag that would follow a golfer using an RF beacon. Also discussed methods of using RF to determine golfer position. Angle to beacon is plausible, but distance to beacon is more complicated using RF.
This will need to be investigated farther.
August 27, 2009 Thur (3 hours):
Met as a team after class to finish writing preliminary project proposal and find mechanical parts for motorized golf bag. Looked at using pre-built "vehicles" such as
shopping carts and electric razor® scooters or electric go-karts. Team determined the golf bag was too mechanically intensive and switched idea to Persistence of Vision (POV) machine similar to the
one made on this webpage:
PIC Clock from MetricMind.com
August 28, 2009 Fri (2 hours):
Met as a team to discus general block diagram and theories behind POV machine. Original block diagram
Discussed potential concerns and road blocks, as well as what information was needed to begin the design process. Need to determine mechanical dimensions, physical structure design, rough parts list, and data
rate requirement for known parts.
WEEK 01 SUMMARY
Accomplishments: Submitted preliminary project proposal.
Weekly Work Total: 6 hours
Project Work Total: 7 hours
August 31, 2009 Mon (3 hours):
Wrote simple LabVIEW program to calculate required data rates and times required for POV machine.
September 1, 2009 Tue (2 hours):
Met as a team to formulate PSSC for presentation in class on September 2. Also drew a different version of the previous diagram to illustrate how the top spinning disk
and the bottom stationary microcontroller would connect to each other and what components they would contain. See picture below.
September 2, 2009 Wed (4 hours):
After giving the PSSC presentations as a team, had a team meeting to discus feedback from presentation as well as written feedback from Preliminary project
proposal. At the team meeting, the attached hardware connection diagram was discussed, and then the team went to the lab to meet Chuck and pick up the tablet PC.
September 3, 2009 Thur (3 hours):
Met as a team to discuss a plan of attack for which topics each team member needs to focus on. While at the meeting, the team made a few important
discoveries/decisions.
•
After the team meeting, Shaun designed a circuit to use with the IR sensor. See attached schematic.
September 4, 2009 Fri (4 hours):
Received the LM3S8962 ARM development board and ulink2 JTAG programmer in the mail, soldered headers to it and labeled the wires on the header. After testing the
soldering and wiring, will post final connection diagram for Eval Board. Also found a good reference document on Phototransistor Switches.
Also, here is a link to the LM3S8962 Evaluation Board Datasheet (to download, right-click link and choose "Save Link As...").
WEEK 02 SUMMARY
Accomplishments: PSSC and project proposal finalized as well as starting the hardware design and component selection process.
Weekly Work Total: 16 hours
Project Work Total: 30 hours
September 7, 2009 Mon (5 hours):
Met as a team to assign deliverables and order of deliverables to begin making progress without overlapping roles. Russell emailed a transcript of the meeting and it is
attached. Also began working on writing the code for the LM3S to work with the IR sensor to measure the RPM of a box fan to determine if it will be suitable for the motor in the
project. Eric also designed a preliminary software flowchart.
September 8, 2009 Tue (5 hours):
Met as a team and discussed how the RF positioning will work and what hardware is required and what resolution is achievable. After that, wrote .m file to calculate
the timing margins and data rates for the system. This is similar to the DataRate LabVIEW vi, but more exhaustive.
The data and units are shown here:
RPM = 1800
NumColumns = 96
NumberLEDperColumn = 32
ColorsPerLED = 3
Diameter = 0.3000 meters
DesiredDisplayWidth = 0.5000 (half a circle)
LEDspacing = 0.0050 meters
spiRate = 12500000 Mbits/s
circumference = 0.9425 meters
DisplayWidth = 0.4800 arc length in meters
DisplayWidthFrac = 0.5093 (fraction of total circle)
DisplayWidthDeg = 183.3465 degrees
RPS = 30 rev/s
TimePerRev = 0.0333 seconds
DisplayTime = 0.0170 seconds (fraction of total revolution time that the display will be updating)
TimePerColumn = 1.7684e-004 seconds
bitsPerColumn = 96 bits
Time2ShiftColumn = 7.6800e-006 seconds
ShiftMargin = 0.0434 (4.34 %)
DegreesPerColumn = 1.9099 degrees
DataPerRev = 9216 bits
DataRatePerRev = 276480 bits/second
DataRatePerRevByte = 34560 bytes/second
VideoDataRate = 8294400 bits/second
VideoDataRateByte = 1036800 bytes/second
secondsPerDegreeOffset = 9.2593e-005 seconds
TimePer10deg = 9.2593e-004 seconds
resolution = 3072 pixels (32 x 96)
bitsPerImage = 9216 bits
BytesPerImage = 1152 bytes
VideoSize = 34560 bytes/second (assumming 30 fps)
The .m file used to generate the data can be found here.
IR Test Circuit
Picture 1 | Picture 2 | Picture 3 |
September 9, 2009 Wed (09.09.09!) (3 hours):
Met as a team to discus the user interface of the final project. The LM3S8962 eval board has an OLED screen and 5 push buttons. These can be used as a user interface, but could be small and tedious. Investigated other
potential options such as character LCD screens and keypads. The largest determining factor will be whether or not the eval board can be used in the final project or must be recreated on the PCB.
The team decided that using 5 pushbuttons to navigate an on-screen menu will be the easiest way to interface with the device. This will allow for software updates to change the program flow and adaptability with no
hardware changes.
September 10, 2009 Thur (7 hours):
Learned how to run the ARM eval board "headless." In order to program the ARM, there is a JTAG connector with a Keil uLink2 programmer/debugger that is has a USB interface to the Keil programming software. The LabVIEW
for ARM package generates the C code that is imported into Keil's uVision3 software that targets the Luminary micro. On first try, the software for the RPM speed feedback would work, but only when the debugger was
connected. After emailing NI for help, found that there is a software option to "disable debugging" which will allow the micro to run without the debugger connected. Limited debugging is still available through the included
USB and ethernet ports on the eval board.
Met as a team to discuss part selection and design priorities. Shaun was assigned the following parts to select:
1. Motor selection
2. Batteries and Type
3. Shift Registers
4. BJTs
The current fan motor (permanent split capacitor 4-pole induction motor from box fan) has a 3/8" flatted shaft with ball bearings. This will provide a fair amount of support for the upper rotating disc, but will be tough to
make a connector that will guarentee concentricity of the disc. A threaded shaft and nut would hold the disc better than a slip collar on the flatted shaft. In order to get the best support possible from this motor, a
shaft adapter will be constructed that converts the 3/8" flatted shaft to a 3/8"-16 threaded bolt.
September 11, 2009 Fri (6 hours):
After much research, could not find shift registers that could supply 3.3V @ 20 mA on all 8 output pins at the same time (160 mA and 528 mW). Many surface mount shift registers are capable of sourcing the 500 mW and 30 mA
per pin, but have a "catch" in the datasheet further down that states "total output current on all pins must not exceed 75 mA total." While it is not often that all pins of the shift register will be "on" at once, the
circuit needs to be capable of handling the condition if it does. Because of this, our circuit will have to use a BJT drive circuit to source the extra current to each LED pin. Since the LED is a common cathode, the circuit
will need to be a PNP BJT or P-channel MOSFET. Since the BJTs are much cheaper, this will be the choice. A test circuit is shown below that will allow the shift registers to use an active-low output to control the RGB leads
of the LEDs. This circuit worked at 3.3V when tested in the lab with a standard Yellow LED from the ECE270 parts kit.
Assistance for this circuit came from this page by Mike Martell.
Ordered samples of SMPS voltage regulators from Linear Technology. One model is the 3.3V fixed output voltage with 3 Amp internal switch, so it needs very few external components. It is model number LT1765EFE-3.3#PBF. The
other regulator is a variable voltage 3V to 25V output at 3A model number LT1765ES8#PBF. They have the same Linear Technology Datasheet.
Tested the IR sensor (used for speed feedback) on the oscilloscope in Lab. The output was a very sharp cornered square wave with negligable rise and fall times and high noise immunity to outside light. The expected interrupt
rate for the final circuit is a 30 Hz pulse from the 1800 RPM motor. Tested the circuit up to 150 Hz and output was just as clean. The circuit tested was the one designed and posted on Sep 8th.
The software algorithm to take the interrupt from the IR sensor and calculate motor speed worked well with the debugger disconected.
Used the IR sensor and oscilloscope to measure fan speed and confirmed the 900 RPM with Fan load measurement from Sep 8th test setup. The 4-pole motor has a synchronous speed of 1800 RPMs with zero slip. Normal induction
motors have around 100-350 RPM slip, and the expected speed with a fan load was around 1600 RPM. Either the motor has 50% slip from synchronous when the fan is connected, or the motor is not the 4-pole induction motor that
it is thought to be. This could cause problems with the final design because all the calculations were based on having a 30 fps update and this motor will only allow a 15 fps update. The project will still work, but the
image will not be as clear and the individual revolutions could possibly be noticable. Will look into other motors to power the machine.
WEEK 03 SUMMARY Finished design limitations calculations for data rate and physical time constraints, designed and tested speed feedback circuit and LED drive circuit.
Accomplishments: Data rate and time analysis, speed feedback and LED drive circuits finished
Weekly Work Total: 26 hours
Project Work Total: 56 hours
September 14, 2009 Mon (3 hours):
Met as a team to discuss upcoming Design Constraint analysis homework. Chose a shift register that will change the software model slightly. The
TI 54AHC594 shift register with storage register will allow the data to be clocked in without effecting the LEDs connected to the pins. This allows the SPI rate of the shift registers to be slowed from 8Mbps to 500kbps.
but adds an extra pin requirement to the micro #3.
Chose a suitable BJT to use in the LED drive circuit -- the Fairchild FMB3906 has two BJTs per SOT-6 package. Also Eric added a datasheets tab
to the Group 7 Homepage for quick reference, as opposed to scanning through the lab notebooks all the time.
Emailed Advanced Circuits sales representative about size and design requirements for the student discount PCB from www.4PCB.com and learned that the maximum board size is 60 sq. in. with
two layers. Multiple separate circuits may be put on a single PCB, but Advanced circuits will ship them on a single board and they will have to be cut apart after shipping, otherwise each PCB is an additional cost.
Started protyping a slip ring for supplying power to the upper disc that would get rid of the need for using/replacing batteries on the upper board. See picture below for a rough sketch of concenpt.
Will keep working on slipring design, but still planning on using batteries at this point. Batteries are much more likely to work at this point. If the slip rings prove more feasible at any point, the team will reevalutate
the use of batteries vs. slip rings.
September 15, 2009 Tue (4 hours):
Met as a team to discuss upcoming Design Constraint analysis homework.
Would batteries be necessary for the Base PCB to maintain time on the clock?
After analyzing the data timing requirements and RF transceiver IC datasheet the POV machine will not be able to do full 30 fps video at 1800 RPM
motor speed. This would require around 270 kbps RF transfer speeds. The uMiRF transceiver from
Sparkfun Electronics has a 250kbps data rate, but must also send checksums and channel information for the packets which lowers the actual data rate the upper
disc will see. Need to investigate possible alternatives to RF transceiver such as IR link.
Found AVAGO Technologies HFBR-2402Z fiber optic receiver that meets data rate requirements, but would be complicated to aim IR led into the receiver input w/out fiber optic cable. Also the Vishay TSHF5410 is a high speed IR
LED capable of 12MHz operation.
Original design used two microcontrollers -- one on the stationary base, and one on the spinning disc. This is possible except that the spinning disc has two equal priority, asynchronous, time critical loops. The spinning
disc must accept data from the RF transceiver whenever it is ready, but it also must shift out data to the shift registers at precise times. If the RF transceiver is ignored data will be lost. If the shift registers are late
or early the image will be skewed. The best way around this is to use two smaller microcontrollers as opposed to a single more powerful one. This will allow the two CPUs to run asynchronously yet still be cost effective.
September 16, 2009 Wed (3 hours):
Met as a team to discuss upcoming Design Constraint analysis homework. Picked out micros and made PowerPoint for TCSP presentation. Also
worked on constructing slip ring prototype design.
September 17, 2009 Thu (6 hours):
Met as a team to discuss upcoming Design Constraint analysis homework. Finished the Design Constraint Analysis homework as a team. This included selecting
a few new parts for the design and double checking the analysis of the power, voltage, and timing requirements.
September 18, 2009 Fri (3 hours):
Worked on slip ring prototype and built the rings. The mounts for the carbon brushes are causing mechanical issues. Getting 27W output motor donated by GE Motors to test with design. Will work on the slip rings after the
new motor is received in case the shaft is a different size.
WEEK 04 SUMMARY
Accomplishments: Finished Design Constraint analysis, selected more parts, investedgated alternative mechanical packaging designs
Weekly Work Total: 19
Project Work Total: 75 hours
September 20, 2009 Sun (3 hours):
Transferred labnotebook sketches and notes from paper to web. Also found a similar LED POV design from http://nazarifar.com/images/spinning-led-globe.jpg.
Need to look into using SIP resistor package to cut down on PCB size for LED drive circuits.
September 21, 2009 Mon (4 hours):
Made notes an drawings on the tablet PC. The pdf of the notes are here.
September 22, 2009 Tue (4 hours):
Made notes an drawings on the tablet PC. The pdf of the notes are here.
The Linear Technolog 3.3V buck regulator takes quite a few external components and has very specific directions for laying out the PCB for
proper performance and heat dissapation. This is not a terrible issue, but the TI 3.3V Buck regulator requires only 6 capacitors, 2 resistors,
and an inductor for proper performance over 2 Amps. The inductor is a commonly stocked part at Mouser.com making the regulator much easier to impliment. This will be used on the power
rail for the LEDs on the LED post.
September 23, 2009 Wed (4 hours):
After Packaging review presentation, team met to work on Packaging Specifications and Design document. In the Packaging presentation many good questions were brought and addressed. Here are some of the imporant ones:
• Would it be possible to use a DC generator instead of a battery on the top disc?
- Yes it would be possible. Currently Shaun is prototyping a carbon brush slip ring that could be used to carry power to the top disc.
• Is 1800 RPMs really necessary for a clear image output?
- 1800 RPM is not an ABSOLUTELY critical number. This is based on the idea that persistence of vision is more effetive at higher frame rates. The team currently has two AC motors to use: one is 900 RPM
and the other is 1500 RPM. Neither of these are the 1800 RPM motors we used in the design constraint analysis. 1800 RPMs is the synchronous speed of a 4 pole AC motor in a 60 Hz electrical system. An induction motor
has to have some slip (the rotor actually spins slower than the synchronous speed) in order to produce torque. The design constrain analysis choise of 1800 RPM was a worst case number, in terms of data rates, and is used
as the ceiling in the calculations.
• Does the team plan on sheilding the spinning assembly for safety?
- The team hadn't planned on it up to this point. The original idea was to place a caution sticker similar to what you would see on the deck of a lawn mower to warn about spinning objects. The post will only
be about 6" tall and the base will be fairly large in comparison. If safety remains an issue, the team will find some type of protective cover for the spinning disc.
• Why does the project need a stationary microcontroller?
- One of the great features about the POV machine is that it will be able to track an RF beacon and adjust the offset angle of the LED display to always face the beacon. In order to detect position the
position detection circuit must remain stationary. The project will also accept user input while in use, so the pushbuttons and OLED screen need to be connected to a stationary microcontroller.
• Why is your team using shift registers and BJTs instead of an LED driver?
- The main reason was due to the RGB LEDs that were going to be used. They were common cathode LEDs and most LED drivers are made for common anode. The LED drivers that supported
common cathode did not offer support for SPI data transfer and multiple LED control. Steve found better surface mount common anode RGB LEDs a few days ago and it never occured to the team to change the schematic. Thanks to
this question, the team has now switched to a TI LED driver that can drive 16 LED pins. This will drastically simplify the PCB layout and
soldering demands for construction. As well, the TI chip is a constant current LED driver which will help ensure that each color of the RGB is mixed evenly to get secondary colors.
At the team meeting, it was confirmed that the enclosure of the stationary base will be made out of wood. Drawings for this can be seen in the Packaging
Specifications and Design document.
The team would like to give a big thanks to Wayne Hughes of GE Motors for donating an AC induction motor for use in the project. This motor will be used to turn the spinning disc.
September 24, 2009 Thu (5 hours):
Met as a team to work on layout and packaging design.
The GE motor is a 4-pole shaded pole motor that runs around 1500 RPM with a 27 W mechanical load connected and around 1748 RPM with no load. This motor has a longer shaft than the fan motor and will be easier to mount the
upper disc to and has more room to develop slip rings. The motor is a 5KSM92HFL0010S motor made by GE Motors. The datasheet tab on the Group 7 homepage has the
mechanical dimensions and performance.
The following pictures show the 5KSM motor as well as the threaded shaft, the t-nut mount for the top disc, and the first slip ring prototype.
5KSM92HFL0010S Motor | Top view of motor with 5/16" T-nut on shaft | Side view of motor with 5/16" T-nut on shaft |
Threaded shaft end | 5/16-18 Shaft Threader | |
Slip Ring Prototype | Carbon Brush for Slip Ring | |
September 25, 2009 Fri (4 hours):
Met with Patrick Morrison at the Purdue Mechanical Engineering Technology Acoustics Lab (METAL) and used the laser to cut out acrylic discs to use as mounts for the brush brackets in the slip ring assemblies.
The mounting discs are 4" diameter 1/8" thick acrylic.
With help from Jessica Dircksen (Purdue BFA '09 Jewelry & Metal Smithing) designed and built copper brackets that would hold the carbon brushes for the sliprings.
Worked with Russell to insert nylon spacers into 3/8" nylon bushing to fit onto the shaft of the 5KSM motor. We tried to use a drill press to bore out the spacer, but could not maintain concentricity. The
slip rings would vibrate too much on the shaft and make too much noise.
September 26, 2009 Sat (6 hours):
Tested the bored-out nylon spacer against two layers of heat shrink tubing to see which would make a better shaft adapter. They both worked, but the heat shrink tubing was very uniform and cause the least
vibration. This was chosen as the preferred material for the shaft adapter. The heatshrink could be attached to the nylon flange and to the shaft with super glue. This was the last step in completing the slip ring
assemblies. There are two brushes per ring in the slip ring assembly. This is to lower the noise in the circuit and also to balance the forces on the motor shaft to lower vibration. See the pictures below for what the
slip ring assemblies look like.
Vin = 6.184 V | Iin = 0.80 A | ||
Vo = 3.362 VDC | Vin Noise = 2.38 Vp-p | ||
C1 = 0 µF | no capacitors |
Vin = 6.190 V | Iin = 0.70 A | ||
Vo = 3.073 VDC | Vin Noise = 1.09 Vp-p | ||
C1 = 220 µF | single 10 V electrolytic |
Vin = 6.187 V | Iin = 0.80 A | ||
Vo = 3.206 VDC | Vin Noise = 1.00 Vp-p | ||
C1 = 680 µF | single 100 V electrolytic |
Vin = 6.190 V | Iin = 0.81 A | ||
Vo = 3.297 VDC | Vin Noise = 1.09 Vp-p | ||
C1 = 680.1 µF | 680 µF 100 V electrolytic in parallel with 0.1 µF ceramic disc |
Vin = 6.194 V | Iin = 0.80 A | ||
Vo = 3.226 VDC | Vin Noise = 2.38 Vp-p | ||
C1 = 0 µF | no capacitor Noise freq = 3.23 Hz |
WEEK 05 SUMMARY
Accomplishments: The team picked out many project compontents, finished the packaging design, changed the schematic for the LED drive circuit, started the schematic layout in PADS, built the motor
mount for the top spinning disc, and built and tested the slip ring assembly.
Weekly Work Total: 30 hours
Project Work Total: 105 hours
September 28, 2009 Mon (4 hours):
Further Tested slip ring design. The same circuit setup was used as in Saturday September 26, except that the Agilient power supply was replaced with
a 12V 30A switch mode power supply. The circuit was tested with different loads and filter capacitors in order to determine whether the
electrical noise from the slip rings was mainly driven by Voltage, current, power, or both. AFTER TAKING THESE RESULTS,
THE TEAM REALIZED THAT THE VERTICAL AND HORIZONTAL SETTING ON THE OSCILLOSCOPE WERE NOT ADEQUATE AND THE NOISE MEASUREMENTS ARE NOT ACCURATE.
Test Number |
Vin (Vdc) | Vout (Vdc) | noise (Vrms) | Io (A) | Rbrush Ω | C1 µF | R1 Ω |
1 | 13.728 | 10.8 | 0.450 | 2.59 | 0.702 | 0 | 4.170 |
2 | 6.010 | 3.2 | 1.0 | 0.82 | 3.42 | 0 | 4.170 |
3 | 6.014 | 3.0 | 0.900 | 1.9 | 1.586 | 0 | 1.6 |
4 | 13.57 | 10.0 | 0.700 | 6.67 | 2.23 | 0 | 1.6 |
5 | 6.013 | 5.9 | 0.100 | 0.006 | 18.8 | 0 | 1000 |
6 | 6.106 | 6.09 | 0.060 | 0.007 | 2.63 | 6800 | 1000 |
7 | 5.00 | 5.026 | 0.090 | n/a | error | 6800 | 1000 |
8 | 3.3 | 3.32 | 0.090 | 0.0032 | 31.3 | 6800 | 1000 |
9 | 6.012 | 3.10 | 0.130 | 0.75 | 3.92 | 6800 | 4.170 |
10 | 6.011 | 3.2 | 0.400 | 0.767 | 3.66 | 680 | 4.170 |
11 | 6.006 | 3.2 | 1 | .767 | 3.66 | 680 + 33mH inductor in series with load | 4.170 |
September 29, 2009 Tue (4 hours):
Picked parts for power supplies and tested transformer
Test Number |
Vrectified Min (Vdc) | Vrectified Max (Vdc) | Vrectified ripple (Vrms) | Vtop Min (Vdc) | Vtop Max (Vdc) | Vtop Average (Vdc) | Vtop noise (Vrms) | Rload (Ω) | Cbulk (µF) | Cfilter (µF) |
1 | 13.62 | 15.31 | 1.69 | 9.53 | 12.34 | 10.9 | 2.81 | 5.6 | 6800 | 1000 |
2 | 18.50 | 18.81 | 0.313 | 17.66 | 18.44 | 17.82 | 0.780 | 1000 | 6800 | 680 |
3 | 18.87 | 19.18 | 0.313 | 18.12 | 19.06 | 18.41 | 0.940 | 11,000 | 6800 | 680 |
4 | 12.46 | 14.15 | 1.688 | 9.06 | 11.09 | 9.86 | 2.03 | 4.170 | 6800 | 680 |
September 30, 2009 Wed (8 hours):
Picked out all parts for buck converter, power supplies, and IR feedback. Worked on the schematic and picked up a PIC 24F development board for code
testing. The PIC24F development board has a PIC24F128GA010 which is similar to the PIC24F32GA002 that our team is using. As long as the code
is written in C and not assembly, the code from the PIC24F128 can be recompiled to run on the PIC24F32 with no issues.
Team met to work on schematic as a group.
October 01, 2009 Thur (12 hours):
Met as a group to work on schematic. The RF transmitter runs on 5V logic and needs to have power. Linear Technology makes a power IC
that will take the output from 2 AA NiMH rechargables and boosts it to 5V up to 200 mA. The total power need of the transmitter is around 80 mA so
this IC will be perfect.
The ARM recommends sourcing no more than 2 mA from any port pin of the LM3S8962 microcontroller so an NPN transistor will be used to
amplify the signal from the port pin to be able to drive the opto-isolator which takes 20mA.
The PIC24F has a parallel master port (PMP) that is used for data transfer between other PIC24F controllers. This seems like a good
feature but this requires a master-slave configuration, and both microcontrollers are also processing time-critical tasks of controller the RF
transceiver and shifting data to the LEDs. This does not work well with the master-slave configuration of the PMP. The software will have to control
the data on the bus without using a built in peripheral. There are two options for controlling the data with 2 control pins. First option: Micro2 has
an output pin that says, "I have data ready" into an input on Micro3 and Micro3 has an output to Micro2 that says, "Thanks, i have read the data."
The other control option is so have Micro3 have an output into Micro2 that says, "I'm ready to read data" and Micro2 will have an output to Micro3
that says, "The data is ready."
WEEK 06 SUMMARY
Accomplishments: Finished first draft of Schematic, Finalized all power supply design, part selection and testing.
Weekly Work Total: 28 hours
Project Work Total: 133 hours
October 5, 2009 Mon (6 hours):
The completed homework assignments were finally returned to day and the team discussed the comments and how to fix/improve the project from them.
Safety of our project is a recurring theme in the packaging design and needs to be addressed. The team is making significant changes to the packaging
to improve the safety. The first change will be to mount to rotating LED post sandwiched in between two discs. The discs have no sharp edges so they
are much safer than the rectangle the post was going to mount to.
David Collins questioned our team why we are using two microcontrollers on the upper spinning disc. Originially this was because there were two
equal priority time-critical and asynchronous funtions of the top disc-- receive data from the RF transceiver and send data to the LEDs. Since the
design recently changed to using LED drivers instead of shift registers, the amount of the CPU time required to send data to the is now much lower.
The PIC24F has 8 interrupt priority levels and a 32MHz clock speed which means that each clock cycle is 31.25 nS and a simple 8 instruction
interrupt could be serviced in as little as 250 nS. The RF transceiver can send data at up to 1Mbps which means that a byte will transfer every
8 µS. At 1800 RPM and a radius of 15 cm for the LED post, displaying 96 columns in 180° means that each column of display will last for
174 µS. The spinning upper disc will take 92.6 µS to move 1°. The position sensor has a target accuracy of ±5°
October 6, 2009 Tue (8 hours):
Need to calculate the force on the LEDs on the spinning post and address safety concerns.
Mass of 8 LEDs = 0.29 grams measures on a My Weigh MX-50 digital scale 0.01 gram accuracy
Mass of single LED = 0.29 / 8 = 0.036 grams per LED
Met as a group to work on PCB layout.
October 7, 2009 Wed (8 hours):
Double checked schematic for top post-- No errors found. The schematic file is here.
Russell came up with the idea for a mounting post that would hold the two plexiglass discs in place. A hand sketch can be found here. The middle of this block could be slimmed down to remove weight. This would result in a hour glass
or sewing bobbin type shape for the final bracket.
The plexiglass discs were originally going to be made out of 1/4" acrylic, but this would make mounting the LED post and balancing the assembly
a more of a challenge than if 2 sheets of 1/8" plexiglass were laminated together. This would allow for "slots" to be cut in one layer of acrylic
and the other layer be left solid so that the post would not slide through the disc. This will add more structural support and also improve the
safety of the spinning assembly of the project.
The PIC24F has a fail safe clock mode (FSCM) that will detect if the signal from the external crystal is bad and enter an error handling routine. Our
team should make use of this feature and put an External Oscillator Error code into the software and give it an LED Blink error. Also need to pick
set delay for the SYSTEM CLOCK stabilization. This delay will be how long the PIC24F waits for the external oscillator to stabilize before entering
the FSCM error mode.
October 8, 2009 Thur (13 hours):
Met as a group to finish PCB layout and work on PCB Layout homework. Used the trace width calculator found at http://desmith.net/NMdS/Electronics/TraceWidth.html to find the proper trace sizes to
use for proper power handling. The largest current that any trace will carry is 3 amps and the largest voltage is 20 Vdc. This is on the lower
PCB and only for a short distance. The preliminary PCB layouts do not have a copper fill yet, as this will just have to be removed if any changes
need to be made. The copper fill will be the last step the PCB layouts.
October 9, 2009 Fri (1 hour):
Posted the Homework #6 PCB Layout homework document.
WEEK 07 SUMMARY
Accomplishments: Finished preliminary PCB layouts, finalized some schematics, switched from 2 PIC microcontrollers to just
one, and designed the mounting bracket for the spinning assembly.
Weekly Work Total: 30 hours
Project Work Total: 163 hours
October 14, 2009 Wed ( 13 hours):
Met as a group to finish Design Review PowerPoint Presentation and rehearse. Here is the Design Review Presentation.
PDFs of the schematics are here:
• Lower Board
Rev 2
• Upper Board
Rev 3
• LED Post
Rev 2
• Transmitter
with WJA amplifier
October 15, 2009 Thu ( 3 hours):
After design review, met as a team to discuss questions and comments and capture all the new information
that was presented and questioned. Here is a list of the comments made after our Design Review presentation.
1) Use wider power traces to DC barrel connectors.
- the thin traces are ground which should be covered when the PCB is flooded. The
team will make larger traces to make sure the power handling is adequate.
2) Make sure the programming pins are brought out to a header!
- This seems to be a complete oversight of not labeling the programming pins. The
team will correct this before continuing with any other design.
3) Would it be possible/make sense to chamfer the corners of the RF transmission line traces?
- It would be a good idea to make sure the trace widths allow for a 50Ω
characteristic impedance. Chamfering the edges should be simple enough because there is plenty of PCB
real estate around the transmission lines.
4) Put 120V and relay on separate Perf Board (as opposed to integrated into the Lower PCB).
- The is will be a simple fix and increase the safety of the project. The perf
board can then be wrapped in electrical tape to make sure that no team members can hurt themselves while
working on the project.
5) Could the carbon brushes be sanded with a Dremel® to make them better seated
on the brass slip ring?
- This would be an excellent way to lower the brush resistance and also reduce the
brush arcing.
6) Will the transient impulses from slip ring arcing cause stiblity problems with the switching
regulators or general noise throughout the circuit?
- This is possible. The primary noise frequency of the slip rings is around 30 Hz,
but the impulse from the arc will have harmonics at many frequencies (due to Fourier transform of impulse)
and could cause interference. Seating the brushes will help with this. Further measurements will have to be
made.
7) It would be a good idea to bring out all pins to debug headers, even if the headers aren't
populated.
- This should be easy to add to the PCB layout.
October 17, 2009 Sat ( 5 hours):
Worked on writing LabVIEW code for the ARM Microcontroller. Wrote many low level functions for the final project
including functions to take an array and output them to the OLED screen on the ARM eval board.
This main function is a function that will take an array (a 2-D array where each value represents the color value
of the pixels of an image) and output that array to the OLED screen.
This is the sub VI that the previous Main VI references. The Draw Picture VI does most of the work from the Main
VI
This is the sub VI that the previous Draw Picture VI references. The Number2RGBgray VI takes the element of the
array and converts that 4-bit grayscale value to a 8-bit RGB value.
This VI will accept an angle (integer value between 360° and -360°) and output a circle on the OLED screen
with a line drawn at that angle. It will also display the angle in integer degrees in the lower right corner of the
display.
The AngleTest VI calls this VI, CircleAngle. The CircleAngle VI generates the circle and line display on the OLED
screen.
WEEK 08 SUMMARY
Accomplishments: Finished design review and continued work on the ARM software.
Weekly Work Total: 21 hours
Project Work Total: 184 hours
October 19, 2009 Mon ( 10 hours):
Met as a team to work on PCB Layout.
October 20, 2009 Tue ( 10 hours):
Met as a team to work on PCB layout.
October 21, 2009 Wed ( 13 hours):
Met as a team to work on PCB layout. Made bill of materials for all 4 PCBs. The bill of materials can be found
here.
October 22, 2009 Thu ( 9 hours):
Met as a team to work on PCB layout and verify proof of parts and parts fit.
October 22, 2009 Fri ( 5 hours):
Met as a team to finish the PCB layout and finish homework 7 and the PCB submission.
PICTURES OF THE LOWER BOARD (PCB 1 OF 4)
Lower Board - Top Side Solder Mask and Silk Screen | Lower Board - Bottom Side Solder Mask and Silk Screen |
Lower Board - Top Side Copper | Lower Board - Bottom Side Copper |
Upper Board - Top Side Solder Mask and Silk Screen | Upper Board - Bottom Side Solder Mask and Silk Screen |
Upper Board - Top Side Copper | Upper Board - Bottom Side Copper |
Transmitter Board - Top Side Solder Mask and Silk Screen | Transmitter Board - Bottom Side Solder Mask and Silk Screen |
Transmitter Board - Top Side Copper | Transmitter Board - Bottom Side Copper |
LED Post - Top Side Solder Mask and Silk Screen | LED Post - Bottom Side Solder Mask and Silk Screen |
LED Post - Top Side Copper | LED Post - Bottom Side Copper |
WEEK 09 SUMMARY
Accomplishments: Made and submitted all 4 PCB's, the bill of materials, updated the schematics
finished the proof of parts.
Weekly Work Total: 47 hours
Project Work Total: 231 hours
October 26, 2009 Mon ( 2 hours):
Met as a team and started working on the software block diagrams for the ARM and the PIC microcontrollers. Also discussed
packaging options for mounting the motor and acrylic discs.
October 27, 2009 Tue ( 4 hours):
Met as a team to discuss the software narrative presentation. The team discussed how the programs will be structured. The
PIC will be primarily interrupt driven and a tiny polling main loop and the ARM will be a polling state machine with a few
interrupts (timer for certain "states" and for button press sensing).
When writing test code in the LabVIEW for ARM package it has been common to run out of space in the heap of the ARM. When LabVIEW
compiles the code to C which is then compiled by µVision into machine code, LabVIEW makes extensive use of the heap. This is
largely due to the fact that some LabVIEW functions are much more complex than what is needed in this project. A workaround for this
is the "inline C node" in LabVIEW or a C function call. µVision will be able to write much cleaner machine code from the hand-
written C code as opposed to the LabVIEW code. The LabVIEW for ARM software package does allow for C function calls and this will
be used extensively for many of the simple functions the ARM needs to perform.
October 28, 2009 Wed ( 5 hours):
Met as a team to finalize the software narrative presentation. The presentation can
be found here.
October 29, 2009 Thu ( 8 hours):
Met as a team to discuss the Software Narrative paper. One of the issues the team discovered is the configuration of the LEDs and
LED drivers on the LED Post. The original idea was for the LED drivers to be configured with the data line in serial so the 6 LED
drivers would be in serial and look like a 96 bit shift register. Each LED driver is capable of driving a 16 single color LEDs,
since we have 32 RGB LEDs this would work fine. The idea was the LED Drivers 1 and 2 would drive the Blue LEDs, LED Drivers 3 and
4 would drive the Green LEDs, and LED Drivers 5 and 6 would drive the Red LEDs. In wiring the LED post this proved very complicated
and the order was changed. LED Driver 1 drives RED of LEDs 0-15. LED Driver 2 drives Green of LEDs 0-15. LED Driver 3 drives Blue
of LEDs 0-15. LED Driver 4 drives Red of LEDs 16-31. LED Driver 5 drives Green of LEDs 16-31. LED Driver 6 Drives Blue of LEDs 16-
31. This makes the data handling for the software a little trickier than if the data should be shifted out with the colors segregated.
LabVIEW for ARM compiles the LabVIEW code into C which is imported into Keil µVision which then compiles and programs the ARM
microcontroller. The LabVIEW code is very large and only allows millisecond precision on the ARM which is not accurate enough for
our use. Therefore, a hybrid of LabVIEW and C code will have to be used program the ARM microcontroller. LabVIEW has a C function
call that can be used and entire subVI's can be written completely in C. This works out nicely because µVision has many drivers
written in C for the Luminary Micro LM3S8962 ARM Cortex M3 microcontroller that our team is using. These will be extensively used
for the image processsing and interrupt functions on the ARM.
The Keil µVision software comes with a Blinky.C example code that has drivers for the push buttons, Timer interrupt, SPI,
and OLED screen. The main program Blinky.C is here in PDF format. The driver
rit128x96x4.C is here in PDF form. The last bit of code needed to run the Blinky example is the
Startup.s is here and written in assembly that is the initialization code for the micro.
October 30, 2009 Fri ( 4 hours):
Finished the Software Software Design Considerations, Narrative, and Documentation paper
that discusses the selection and rational for the software architecture (interrupt, polling, or statemachine). This includes
discussion on what peripherals will be used and a flow chart of the main program. Most all of the required main fuctions for the
ARM and many of the functions for the PIC are outlined in detail and are ready to be written and tested.
WEEK 10 SUMMARY
Accomplishments: Started writing the software for the project and completed the software outline and flow. Also
started the psuedo-code for most functions in software for the ARM and the PIC.
Weekly Work Total: 23 hours
Project Work Total: 254 hours
November 2, 2009 Mon ( 5 hours):
Wrote the code for to test the SPI port of the ARM eval board. A code snippet is shown below.
The previous VI caused an error while compiling. Since the OLED is multiplexed with the other SPI outputs, the Blinky.C code was
ran and the SSI port outputs were measured with an Agilent 54624A Oscilloscope. The output plots are shown below.
November 3, 2009 Tue ( 5 hours):
Met as a team to discus the code structure for handling the pixel map generation. Details are posted on Russell's
lab notebook.
November 4, 2009 Wed ( 0 hours):
Did not make any progress on the project as I was out of town at a job interview. The team presented the
Patent Liability Analysis Presentation .
November 5, 2009 Thu ( 0 hours):
Did not make any progress on the project as I was out of town at a job interview.
November 6, 2009 Fri ( 0 hours):
Did not make any progress on the project as I was out of town at a job interview. The team completed the
Patent Liability Analysis document.
WEEK 11 SUMMARY
Accomplishments: Continued writing software for testing the ARM microcontroller
and analized the logic output of the SPI (SSI) port.
Weekly Work Total: 10 hours
Project Work Total: 264 hours
November 9, 2009 Mon ( 3 hours):
Met as a team to work on soldering and debugging the circuit boards for the project. The LED post is completely
soldered and a video of it working is shown below.
The LED post uses TI tlc59025 constant current LED drivers. These are latched shift registers that accept an
SPI input into the memory of the shift registers and have a latch to control the output pins of the LED drivers.
Each LED driver can drive 16 single color LEDs. There are 32 RGB LEDs, so that requires 6 LED drivers.
November 10, 2009 Tue ( 5 hours):
Met as a team to discuss issues with the power supply on the upper board. The 5 V switching regulator is capable of
holding a 5.01 V average output, but there is a 50 MHz 0.70 Vp-p undersdamped oscillation. This occurs twice
every switching period, when the MOSFET turns on and off. This oscillation is due to the underdamped RLC circuit in the
output of the buck converter. This is most likely due to much larger capacitor ESR than the TI tps54357 synchronous 3.0A
fixed output 5V regulator. The regulator runs at a 500 KHz nominal switching frequency. After testing the circuit the actual
switching frequency is around 490 KHz.
November 11, 2009 Wed ( 0 hours):
Did not make any progress on the project as I had a job interview out of town. The team presented the
Reliability and Safety Presentation.
November 12, 2009 Thu ( 5 hours):
Met as a team to discuss the software and the power supply issues. Russell discovered that the ESR of the first of the 3
output capacitors of the 5V Buck regulator is much too large and is creating an unstable condition in the deadtime
portion of the control loop. This can be adjusted by using a smaller output capacitance with lower ESR and by putting multiple
low ESR capacitors in parallel to lower the resistence even more.
Worked on the user menu for the ARM microcontroller in LabVIEW for ARM.
List of VI's
- Main
Top Level VI that calls all the sub VIs.
- Clear Screen
Clears the OLED screen to be all black.
- Blank Screen Memory
Clears the memory of the OLED screen without clearing the display.
- Draw String
Draws a string on the OLED given a line 0-7.
- LineNumber2XY
Given a line number (0-7) generates the pixel location on the OLED.
- Draw Rectangle
Draws the gray rectangle behind a single line of text.
- Scan Buttons
Scans all the input buttons and outputs button states.
- Interrupt Handler
Timer Interrupt that blinks the status LED to know the code is working.
- Main Menu
Displays the main user menu on the OLED.
- Options Menu
Displays the options menu on the OLED.
November 13, 2009 Fri ( 5 hours):
Met as a team to discuss our current progress and prioritize what tasks are left to complete the project. Coding is the most
important issue on hand, and second is the hardware soldering and testing.
Shaun and Steve went to the METALs lab to work with Patrick Morrison to use the Epilog laser to cut out one of the plexiglass
discs for the upper rotating assembly. The disc is 13" in diameter and cut from 1/4" acrylic. A 0.08" wide x 2.05" long x 0.1"
deep groove was cut for the LED post to fit securely in.
Submitted the Reliability and Safety Report.
Code left to write:
- Individual functions
- SPI sub VIs
- A/D to Angle VI
- Custom text input menu
- Debug functions
- Pixel map generation function
WEEK 12 SUMMARY
Accomplishments: Finished and tested the LED post and its completed. Wrote many of the Sub VI's for the ARM
and the User Menu. Also cut the first of two discs for rotating assembly.
Weekly Work Total: 18 hours
Project Work Total: 282 hours
November 16, 2009 Mon ( 5 hours):
Tested the power supply on the upper board with the new capactor values.
C7 = 33uF electrolytic cap (AFK336M10C12T)
C8 = 47uF ceramic cap (JMK316BJ476ML-T)
C9 = 0.1uF bypass ceramic cap
The picture below is the output of the PSU on the upper board using a 510Ω load resistor. The top signal with the cursors
around it are the 5V output. the bottom signal is the 3.3V output from the LDO.
November 17, 2009 Tue ( 11 hours):
Tested the 5V switching regulator on a different oscilloscope with a different probe and the ripple was only 200 mV worst case.
This was clean enough power to run the circuit without digital glitches, so the rest of the board can now be populated and tested.
November 18, 2009 Wed ( 11 hours):
Continued populated the PCB and testing each component as it was populated.
November 19, 2009 Thu ( 1 hours):
Worked on designing the new mouting assembly for the motor and disc. Since the old motor has a bent shaft, the original
fan motor ("recycled" from a Lasko Box fan) will be used. It has a 3/8" flatted shaft that works well with the 3/8" slip rings.
November 20, 2009 Fri ( 0 hours):
No significant progress was made due to an out of town interview.
WEEK 13 SUMMARY
Accomplishments: "Fixed" power supply and continued soldering
the PCBs. Also worked on integrating all the
components together.
Weekly Work Total: 28 hours
Project Work Total: 310 hours
November 23, 2009 Mon ( 3 hours):
Worked on finishing the rest of the PCBs and starting the packaging for the POV Machine.
November 24, 2009 Tue ( 3 hours):
Met as a team to discuss what the best approach was to finish building the project. There are hangups with the ARM
code being very bulky when generated by LabVIEW, and the details on the packaging aren't finalized. Went to the MET
Acoustics Lab (METAL) with Steve to work with Patrick Morrison to cut a new acrylic disc for the new shaft size.
November 27, 2009 Fri ( 3 hours):
Worked with Jessica Dircksen (BFA Metalsmithing Purdue 2009) to help resolder the broken slip ring brush holders.
WEEK 14 SUMMARY
Accomplishments: Worked on packaging and ARM software.
Weekly Work Total: 9 hours
Project Work Total: 319 hours
November 30, 2009 Mon ( 5 hours):
Worked with team on packaging. Mounted the motor inside the box.
December 1, 2009 Tue ( 10 hours):
Worked on constructing the packaging of the project and trying to get all of the pieces working together. Assembled
the slip rings and got power to the upper board through the slip rings.
December 2, 2009 Wed ( 12 hours):
The code for the ARM microcontroller is behind schedule, but I am still making progress. There are two major hangups
for this delay. The first major problem has been interfacing to the ARM using the SPI port. The evaluation board has
an onboard OLED which by default in LabVIEW for ARM, has control of the SPI. Using the SPI port was not very well
documented, but I got excellent support from the National Instruments engineers. The initialization of the SPI will
in LabVIEW will allow for the user to create a new chip select pin for the SPI port. The SPI port must be re-initialized
everytime a different device is used on the SPI port. The following LabVIEW VI was created by a PSE and NI and shows
how to "multiplex" the SPI port by initializing a new CS pin.
The other issue with programming the ARM is using bitwise functions or array functions to process the pixel maps in
the LabVIEW for ARM program. The beauty of LabVIEW is that it makes realatively complex functions and embedded processes
simple to code, but you lose the low level control. The low level control is possible, but it takes much more effort.
December 3, 2009 Thu ( 12 hours):
On this day, some of the toils of our labor came to fruition and the first sign of meaningful light was emitted
from the POV machine. The YouTube video shown below is a video of the first complete test of the LED display mounted
to the rotating disc in the box. The video shows a picture of a smiley face, but a picture of an American flag and
Canadian flag were also tested.
The images were pre-loaded into the flash memory of the PIC microcontroller on the rotating assembly. The code for
the PIC also did not use dynamic speed feedback in generating the image. The next step in the code is to add feedback
so that the image offset and image width will be independent of motor speed.
Another issue that the POV machine is having is balance. Due to the imbalance of the disc, the motor cannot reach
full speed. The team has a balancing tool that will be used to fix this issue.
December 4, 2009 Fri ( 7 hours):
While attempting to balance the disc, the team discovered that there was a problem with the balancing assumptions. The
team assumed that balancing the disc while stationary (static) would translate to balancing the disc while rotating. This
was based on the assumption that the majority of the mass was in the same plane as the rotating acrylic disc. Due to the
5" height of the LED post and mounting bracket, there is a large mass in a plane above the plane of the rotating acrylic
disc. This causes an outward force creating a moment about the axis and makes a vibration. In order balance the disc, the
moment of the counter balance must be equal and opposite to the moment of the LED post.
Balancing tool for the disc | Two parts of the balancing tool | Disc with counter balance post |
December 5, 2009 Sat ( 9 hours):
Made the final edits to the LabVIEW for ARM code and also worked on the code for the LabVIEW Paint.vi that was
writted so that the pixel maps for the POV machine could be drawn in a program similar to microsoft paint. The
program outputs the bitstream that our PIC microcontroller shifts out to the LED post. This file is 1152 bytes
in size. The program outputs a .txt file that can be copy-pasted into the .C file for the PIC24F and a .bmp file that
can be used to keep track of the pixel maps.
WEEK 15 SUMMARY
Accomplishments: Completed much of the software and successfully ran the first test run of the machine by displaying a smiley face.
Weekly Work Total: 55 hours
Project Work Total: 374 hours
December 6, 2009 Sun ( 7 hours):
Worked on packaging, programing the PIC24F and the ARM. While programming the ARM in LabVIEW for ARM, we ran out of
RAM on chip. The LabVIEW for ARM software loads all data into RAM before using it, so all constants take up RAM as
well as Flash. The LM3S8962 has 64K of on chip RAM. The software will have to be rewritten to save memory. I wrote an
email to support at National Instruments for tips on ways to save memory.
December 7, 2009 Mon ( 13 hours):
Worked on packing the unit and finishing the software on the PIC24F on the upper board. Since communicating with the
RF transceiver with the SPI on the ARM would be incredibly challenging so an extra PIC24F was used to interface
between the ARM and the &mirco;MiRF transceiver. They were connected with a 6-bit interface that was manually written
to send information on preset pixel maps and angle offsets. The bits are a binary representation of a base 10 number
between 0 and 63. The numbers are represented as follows:
0 - blank display
1:15 - preset image
16 - custom image
17:54 - angle offsets between 0 and 350° in 10° incriments
55:63 - unused
NI support replied on great ways to save memory. It is possible to write functions in C and add them to the LabVIEW
project or just use an inline C node. This way I could define constants in flash and then call them in C so that they
are not loaded into RAM. The other tip was to edit the startup.s file in the µVision project because the
operating system loaded onto the ARM to handle the threading in LabVIEW uses a fixed amount of RAM, whether it is
necessary or not. By default the Heap for the OS is 0x8000. It is possible to lower this amount of memory used, but
there is no guarentee that the system won't crash.
December 8, 2009 Tue ( 12 hours):
The team worked to finish building the wooden box and test the device. The team got the system working and generated
a few pixel maps. Pictures of the new pixel maps on the working POV machine are shown below.
Picture of the American Flag | Team 7 logo (Yes, the "e" is backwards on purpose) |
December 9, 2009 Wed ( 6 hours):
Put the finishing touches on the POV machine before the PSSC demonstration in TCSP. Updated the code on the lower
PIC so that the offset on the OLED would match the offset on the POV display. The natural 0° of the POV display
is offset about 210° offset from the 0° of the unit circle. Also had David check off 4 of the 5 PSSCs (1,2,4, & 5).
PSSC 3 - "An ability to track the angle of arrival of an RF beacon" is much harder and will not be feasible by the end of the
semester. After TCSP, the team asked Dr. Meyer if we could change that PSSC to an attainable one and he agreed. The team started
sanding and prepping the box of the POV machine for painting in preparation for the presentations to ECE362 and ECE270 on Friday.
December 10, 2009 Thu ( 9 hours):
Painted the box of the POV machine and added the software to include animations of a stick figure throwing a grenade and a walking
dinosaur. The animations were drawn by hand in the LabVIEW Paint.vi Each picture of the animation had to be drawn
individually. The program on the PIC24F scrolls through the pictures. Also made the presentation for the ECE362 class.
The animation of the stick figure throwing a grenade is shown below.
The animation of the dino-saurus is shown below.
Also made a video segment used in the ECE362 Presentation. The YouTube clip is shown below.
December 11, 2009 Fri ( 11 hours):
Just past midnight while testing the POV machine, the motor overheated and something inside the packaging started
smoking. The team quickly disassembled the package to find what had broken and the only component that was hot was
the motor that turn the rotating assembly. When the motor had cooled the power was restored and the motor would not
turn back on. The windings of the motor looked normal, and the switch and relay were in complete working order, so it
was determined that the 4µF run capacitor on the permanent split capacitor motor from a box fan motor. We did
not have a replacement capacitor, so the motor from another box fan was replaced. The new box fan motor had a 5micro;
F capacitor. Since the two motors had a different value of capacitance, the entire motors were swapped as opposed to
just the capacitor. This was finished just in time for the ECE362 presentation. The project is completely working and
is documented in our final presentation and project video.
Merry Christmas!
WEEK 16 SUMMARY
Accomplishments: Completed all 5 PSSCs and finished the final packaging of the project. Presented the POV machine to the TCSP and the ECE362 class.
Weekly Work Total: 58 hours
Project Work Total: 432 hours