PLEASE READ BEFORE BEGINNING General Circuit Description: The circuit is a two stage oscillator with regulated +5VDC power supply, four IR LEDs, and Darlington transistor driver. A. Power supply - The power supply is a simple three component assembly that runs from a standard 9V battery (not supplied). B. LED Driver - The LEDs provided by the First Robotics kit are to be used with this, the output side of the IR Beacon. The other parts, resistors and Darlington transistors are in the kit. C. Two Stage Oscillator - 1. Stage one is either a 1 ms pulse rate, 100 Hz square wave generator (Type 0), or a 2 ms 100 Hz square wave generator. Each variation is identical to the other with the exception of just a few capacitors and resistors. 2. Stage two is a 40 KHz, square wave oscillator. The pulse period of a 40 KHz signal is 25 us. When fully assembled the kit will provide a 40 KHz square wave, burst output for either 1 or 2 ms duration at a 100 Hz rate. Precision resistors should achieve fidelity with the published First Robotics requirements at or above a 90% rate. Higher fidelity is possible, but would require multi-turn potentiometers in this particular circuit. The prototype will cause a 40KHz IR receiver to respond! NOTE: One IR sensing strip is provided to you in one of the kits for the purpose of assisting you in verifying the "general" health of the output from the IR LEDs. For greater accuracy in measuring the circuit output, an oscilloscope or equivalent tool would likely be necessary. Instructions for building a 100Hz Type 0 or Type 1 IR Beacon for the 2004 First Robotics Competition using the kits. 1) Get a kit of parts, some 28 or 30 guage wire-wrap wire, and some wire-wrapping tools. (Examples are needle nose pliers, flush cutters, wrapping tool, and wire stripper, fine-tip soldering iron, flux-core solder, continuity checker or Ohm meter, etc.) If you do not have these tools they are available from Radio Shack (soon to be out-of-business). Wire-Wrapping Tool: part number 276-1570 Wire-Wrapping Wire: part numbers 278-501, 278-502, & 278-503 (One roll will probably build more than one circuit, but using colored wire for specific circuit functions like +V, Gnd, and Signals, etc. will make the work easier.) 2) Decide if you are going to build a Type 0 or Type 1 Beacon. Select the right kit. There are two kits, one each for the 0 and 1 devices, respectively. 3) Identitify each component in the kit and where it fits into the circuit. NOTE: The Type 0 and Type 1 Beacons are interchangeable in the overall circuit. It is only stage one (described above) that is unique. Use the Layout & Assembly drawing to assist you. 4) After you've convinced yourself that you have all the parts, assemble the circuit on the perfboard. a. place the parts through the holes on the perfboard. b. install the wire-wrap sockets in place of the 555 timers. b. tack solder the parts in place using the least amount of solder necessary to create a clean solder filet. c. inside the handle of the wire-wrap tool is a stripper for the wire wrap wire. d. strip away about one inch of insulation before beginning each wrap. e. a good wrap is one that has a smooth, single layer of wraps starting with a few insulated turns and ending in several stripped wire wrap turns. f. always leave a little slack (service loop) in the wire as you go between pins. 5) Before you install the two 555 timers, be sure to verify your circuit with an Ohm meter or volt meter.