The controller is actually just an ATTiny2313, running of it’s internal RC oscillator at 8MHz, soldered onto an universal board with a few resistors and wires. There are no control items - no buttons, no nothing. It just does what it does - makes the effect of LEDs randomly fading in and out using 9 channels of PWM. Unfortunately, the processor has only a few hardware PWM channels, so some of the channels had to be done by software.
The DTMF decoder can be powered from a 9V battery or from your parallel printer port. It can detect and display all 16 DTMF digits on your computer screen in real-time. The Window’s program can be placed in the minimize mode and still detect tones while you use your computer to do other things.
SAEBRTrack is a low earth orbit (leo) satellite tracking system. It was originally designed to use inexpensive TV antenna rotators, like the “Orbit 360” sold at many hardware stores. However, the author recently modified the code and the hardware to work with the Yaesu G-5500 elevation-azimuth dual controller. The G-5500 certainly is a much better way to go, even with the fairly high price tag.
The Arduino system offers an easy and open-source method for programming microcontrollers. Normally this means using a serial cable or USB cable attached directly to the microcontroller project. But what if your project is floating in a weather balloon, glued to the bottom of a swimming pool or baked into a loaf of bread? It would be great to upload code changes wirelessly, and even greater if you could do it from several kilometers away.
The following example demonstrates how to build a complete wireless solution for uploading code to a remote Arduino microcontroller using a couple of XBee radios, and a handy function for accomplishing wireless resets.
Arduino Wirelessly Programming System Based on XBee:[Link]
The ARDF controller was created after a request to be able to play random audiofiles for an ARDF transmitter, most existing designs were based on an 16F84, a somewhat aging design and better controllers are currently available. Also most controllers had a 5-10 mA current drain which can be improved, this design requires less than 400 uA.
To allow a very small controller footprint and flexible configuration the timer is not configured with (dip) switches but via a serial connection and a host PC. The memory option is optional and is only required for a wave file playback, all other options (CW, Single Tone, Tone Sequences and Audio Effects) do not require the I2C memory chip.
