Aqua Teen Hunger Force Animated LED Art

On January 31, 2007 Boston was shutdown when pieces of LED artwork that looked like characters from the Cartoon Network show Aqua Teen Hunger Force were mistaken for bombs. Ever since this occurred I have wanted to build my own version to hang up in my apartment.

My version is designed to look like the character Ignignokt; in case you don't watch the show Ignignokt and Err (his sidekick) are Mooninites (residents of the moon, designed to look like characters from an 8 bit video game) who occasionally come down to Earth to annoy the Aqua Teens. I chose Ignignokt because he is green and blue (Err is purple and blue) and green LEDs are cheaper than purple LEDs. My design used 72 green and 40 blue LEDs.

I got my LEDs from Mouser and I chose them based primarily on their diffusion angle (over 40 degrees), which allows for better viewing angles than other LEDs. In order for an LED array like this to function properly the LEDs must be wired in parallel (ie. all of the cathodes are connected together as well as all of the anodes). I also had to subdivide the LEDs into a group of all of the green LEDs (D6 on the schematic) and all of the blue LEDs (D5 on the schematic). This had to be done because the LEDs were different types and there were more greens than blues, causing the current draw of the groups to be unbalanced. This created a problem where only the green group would light, consequently, I adjusted the resistor values such that I balanced the current drawn by both LED groups. There are also four additional groups to create the effect of Ignignokt giving the finger. These groups are controlled by a PIC16F84A microcontroller which orchestrates the animation of the LEDs. As shown in the schematic, group D1 is the hand and groups D2-D4 are the finger. The code (written in PicBasic) is very simple, involving only turning on specific digital outputs of the PIC for set periods of time. I can power the whole thing off a 9 Volt battery using a power circuit similar to that shown in the schematic for my GPS project (I substituted a 78L05 for the 7805 voltage regulator since this circuit draws less current). Check out the video to see Ignignokt in action.

• PicBasic Code

Parts:

• Green LEDs
• Blue LEDs
• PIC16F84A

Trippy RGB Light Redux

I decided to rebuild the Trippy RGB Light with a single RGB LED instead of three individual LEDs. I also changed from a 3 Volt supply to a 4.5 Volt supply. As a result I also had to change the resistor values (Blue - 150 Ohm, Red & Green - 270 Ohm). The video shows a marked improvement over the previous version.

Trippy RGB Light

This is another project that modifies the MiniPOV kit, similar to the LED Cube project I did previously. This time, instead of an LED matrix, one Red, one Green, and one Blue LED are used to create a multi-color light show by utilizing pulse-width modulation of the AVR's output. The construction is very similar to the LED Cube in that I also built the RGB from scratch. I did not, however, include an ISP header this time around because I felt the original program was adequate for a project of this scale. If I later decide to rebuild this project using multiple better quality LEDs I will definitely include an ISP header to be able to reprogram the RGB for other light shows.

In order to program the RGB Light I had to modify the makefile code for use with my USBTiny ISP in the same manner I did in the LED Cube project. This project is very simple to build and it produces an interesting light show. With some better quality LEDs with more diffuse viewing angles this could be even better. I will most likely rebuild this at some point in the future with more appropriate LEDs. Check out the video of my Trippy RGB Light in action (with a plastic bag between the RGB Light and the camera to diffuse the light for better color mixing).

Links

• Trippy RGB Light Schematic
• Trippy RGB Light Firmware (C code)
• Trippy RGB Light makefile
  

LED Camera Light

This is project is originally from ProdMod and I built my version of one in about an hour. I had been looking for a way to put a camera light on my digital camera, especially for video, and this project fits the bill perfectly. All this camera light consists of is a modified 4-AAA battery case (with built-in switch) which has a 3/4" long 1/4" cap screw passing through it and 3 white LEDs wired to the batteries. To use it you simply thread the screw into the tripod mount on your camera and turn it on.

I used a different parts source than the original article, getting both the white LEDs and AAA battery case from Mouser Electronics. The cap screw can be purchased as a pack of 2 from Home Depot for $0.88. Other than that my camera light went together the same as the original article, with the exception that I used a 15 Ohm resistor instead of a 10 Ohm to protect the LEDs. I chose this in order to add the flexibility of using regular alkaline batteries or rechargeable batteries. Since alkaline batteries produce 1.5 Volts typically, three alkalines produce 4.5 Volts. Rechargeable nickel-metal-hydride batteries produce 1.2 Volts typically, so three batteries produce 3.6 Volts. This voltage differential means the current limiting needed to keep each LED's current draw under 2o mA is different if using alkalines or NiMH batteries. For the LEDs I chose from Mouser, the 15 Ohm resistor used with alkalines produces a current of 63 mA or 21 mA per LED. If using NiMH batteries this would amount to approx 17 mA per LED. Therefore, the 15 Ohm resistor is a good compromise that allows me to not worry about battery type.

LED Cube

This is another project I found via the Make Magazine Podcast. It is very simple to build, especially if you do what the original project recommends and start with the MiniPOV kit. Just follow the podcast's directions and modify the kit to get up and running. I took a somewhat different route. Since the MiniPOV is based off of an Atmel AVR 2313 microcontroller, and I have several of these chips and an AVR programmer, I built the project from scratch and modified it to use the AVR's in-system-programming (ISP) capability instead of a serial port like the MiniPOV. Otherwise my hardware ended up identical to the original.

On the software end I had to make some changes to the code from the project's ZIP file. I modified makefile to look for my USBTiny ISP instead of a serial port. Then all I had to do was follow the remainder of the podcast's instructions to compile, build and program the AVR. To make different LED animations all that is required is modify the LED code matrix in the ledcube.c file to make different LED configurations light up for different amounts of time. Check out the video of one of my animations. Definitely a fun, easy project.

Links

• Make Podcast LED Cube Video
• Make Podcast LED Cube Files
• Crazy Huge LED Cubes