So, this project was sidelined until I had to make another BatchPCB purchase.  Thankfully it wasn’t too long until I had the opportunity to work on it again! The current setup is basically 4 of the original 4 RGB LED Controller boards and 12 of the updated DR1r3 boards. All 16 are wired in parallel and being controlled by my desktop machine. You can see an extended version of this RGB test sequence after the break and I’m also including the (uncommented, sorry!) Processing 1.1 code that I used to control the boards.

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I recently began working on a consulting project that required the creation of some PCBs.  Since I have had such great success with BatchPCB.com in the past, I decided to use them again to fab the custom PCBs.  The BatchPCB purchasing system adds a few static fees (set-up, handling, and shipping), so I felt that this was as good a time as any to make some additional of my PIC16F628 4 RGB LED PWM Controller boards with a couple of modifications.

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I am a big fan of LEDs.  Bright, colorful, flashing LEDs.  So, given my affinity for LEDs, I decided to work on a controller that me and a few of my friends could use as an art project/passive information display.  I have posted videos from the first prototypes (here and here), but it has been tough to dedicate time to further development given my research, so I thought I would post the information so that anyone can take the design and modify it to their liking!

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I’ve been working on a project in my spare time with two friends to create some ambient light controllers, so I thought I’d just post two short videos to demonstrate the current state of the project.  In the current iteration, they can be used as wall-washers or they can be enclosed to create ambient light cubes/spheres/pentagonal cupolas/rhombo-hexagonal dodecahedrons/etc.  Each module is addressable and uses a PIC16F628 to control each of the RGB LEDs (which were purchased from the eBay seller jeledhk with the description “Superflux RGB 5mm R/H LEDLamp 8Kmcd COMMON CATHODE”).  The PCBs were created using BatchPCB.com for $5 each (+ ~$15 total for S&H and setup) and are beautifully etched, drilled, and silkscreened (although it took about 1.5 months to receive them).  Ok, less talk, more videos; one video on the front page and another after the jump:

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It has been a long time since I’ve done any microcontroller work, so I decided to get back into the swing of things when 2 of my friends and I decided on collaborating on an interactive “art” piece.  Details are forthcoming, but in the meantime, a photo and a video of one of the LED components (video after the break):

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My original intention for my PIC16F88 Delorme Tripmate GPS Logger and GPS Logger with Time and Speed was to log my runs around Lafayette and West Lafayette. However, I’ve found that the weight of the GPS makes it a real pain to lug it around. Running around with a weight bouncing around in my backpack is no fun. Now that it has gotten warmer and the sun is shining ’til 9 PM (really more like 9:30 PM), I’ve been biking quite a bit. The lower impact nature of bike riding makes it much easier to carry the Tripmate GPS receiver. So I took went out this afternoon for a ride to see how it performs:

And the ride did not turn out too bad! (Click the image above to see a better view of the route, outlined in yellow.) There are some problems with the logging, but this can be attributed to the quality of the fix (most likely 2-D for most of the ride) and the tendency for the GPS to loose its fix when the sky was occluded. See the upper right of the path where I went biking through the woods and you can see that it lost the fix from the time I entered the woods to the time I left them. Continue to the post for more information and the updated firmware. (more…)

I’ve updated my PIC16F88 Delorme Tripmate GPS Logger, so it now includes time and speed logging. Using the trip information recorded by the GPS logger, you now have even more variables to play with. For example, using time and velocity information, one can plot not only the speed, but also the acceleration of the car (dv/dt) for a trip:

Continue to the post for more information about the updated firmware, usage instructions, and limitations of this firmware. (more…)

This project focused on creating a simple serial data logger for the Delorme Tripmate (also known as the GPSTripmate). The Tripmate is an older GPS receiver that can be purchased on eBay for <$20. I happen to have one that my family used a couple of years ago and it is still in great shape. It has been sitting in the back of my car for the past four years, so I finally decided to put it to good use. The plan was to create a GPS data logger that would record the position of the unit and allow me to read back the latitude and longitude after acquiring the data. My ultimate goal will be to use a small backpack to record my runs (once the weather warms up). This was a fun experiment because not only did I need to interface the PIC16F88 to the Tripmate, but I also needed to parse the output and implement an efficient storage solution. Read on to find out more information about the project, see the schematic and soure code I wrote, and find out how the data was visualized. (more…)

A friend at Purdue University (Sumanth Peddamatham) helped motivate and inspire me to create a high voltage flyback transformer driver for a computer CRT flyback transformer. While the schematic and code for driving the transformer are extremely straightforward and simple, finding and obtaining a high quality solid state flyback transformer can be difficult. Please note that the voltages generated by the flyback transformer are potentially very dangerous, so extreme care must be exercised when building and/or using the schematic presented in this project. Diode split flyback transformers (like the one used in this project) can output 25kV or more. (more…)

Using the PIC18F2550 GLCD Text Test as a basis for further experimentation, I put together a simple and accurate graphical oscilloscope using a PIC18F2550 microcontroller and a AGM1264F graphical LCD. The oscilloscope measures the average voltage, the maximum voltage, the minimum voltage, the peak-to-peak voltage, and the zero-crossing frequency for a DC signal over 100 samples. The oscilloscope has a built in edge trigger function that can be set to capture on rise or fall (or disabled altogether). The time scale for the display is variable and can be easily redefined using the changeTimeDivision function. Likewise, the voltage range can be change to 0-5V, 0-2.5V, and 0-1.25V. The main limitations of this oscilloscope include relatively slow acquisition time and sampling rate (~60kHz) and the fact that the inputs are limited by the constraints of the internal ADC. However, it is a very nice display and I highly suggest you view the videos to see it in action. (more…)