Electric Fish Electric Organ Discharge Generator


The goal of this project was to build a field-portable EOD generator. The EOD generator will be used to electrically "simulate" fish.


We used an Atmel STK-200 development board with an AT90s8515 flash-programmable microcontroller (mcu) on-board. Communications to the host PC were handled by the 8515 UART. A port of the mcu was used to drive an 8-bit digital-to-analog converter (Analog Devices AD557). Another port was used to detect a button push. The button starts playback of the currently stored waveform. If no wavefrom has been loaded from the PC, then a button push causes a calibration waveform to be played. A third port was used to run two LEDS. One LED lights during playback, the other lights during data download from the PC.


There are four processes which run on the microcontroller:

AVR assembler code. is the program running on the mcu.

The waveforms were recorded and stored as standard ASCII formated numbers. To communicate with the mcu, the waveform had to be encoded as explained above. A MATLAB program which performs the encoding is included.


There are two separate circuits which were built, the EOD generator and an amplifier to boost the voltage level and current drive.

EOD generator:


The "slow" switch is shown in the normal (unpushed) position. When pushed, it reduces the bandwidth of the amplifier to less than one Hz. This allows transient-free switching of the source.

Amp and EOD generator.