Oscilloscope and Physiological Stimulator
using a microcontroller and a TV


This is an attempt to make a complete student electrophysiological instrument based on a cheap microcontroller. The porject is based on an earlier TVscope.

The Vout (to the right) is driven from an opamp with input taken from an 7-bit R2R ladder conencted to PORTC on the MCU. The ExpressPCB (do a save as... on the following link and use ExpressPCB software) design file.

Parts list (Digikey part numbers):

TVnuS details

Scope features:

Stimulator features

The CodeVision C program is loaded on the Atmel Mega32. Please write me if you want the source code. There are actually two versions of the code currently. The first does only single pulses, the second does double pulses also. When compiling, set the options to optimize for speed and to include floats in print statements, and set the data stack size to 100 bytes. Set the clock fuze bits to all-unchecked. You may need to uncheck the signature-check box.

The above image shows a stimulator pulse. At the bottom of the display there is a RUN/STP/ARM indicator, cursor readout of time and voltage on the trace, a LEVL/STIM/FREE trigger indicator, and the trigger level. At the top of the display is REPEAT/ONE/TWO/OFF pulse mode indicator, the pulse duration, interpulse spacing, and the pulse amplitude.


Internally, the program is divided into two parts:


Copyright 2003 - Cornell University - Bruce Land