Surely for the price of an 8bit A-D and a few other simple components it would be much easier to use the parallel port to sample the data. Rob At 10:49 15/05/2003 +0000, you wrote:
while at school i was quite good at soldering so i want i would be happy to put a prottype circiut together for you? if you could send me a circuit/pcb design? I cant help you with the software writng tho, sorry.
Not aware of any school friendly robotics or data logging stuff for Linux.
I've been playing around with a design for a low cost one channel datalogging system, which would be ideal for a simple C project.
Outline concept is this...
Sound card is used to generate an AC signal which is conditioned to 0.7 volts (using a diode and resistor) which is then split across a potential divider - one side of which is fixed resistor other side is thermistor / LDR.
Stereo mike input is then used to compare the voltage across the whole PD with the voltage across the thermistor / LDR.
Data logging process is simple - write to a file of fixed maximum size with initial sampling rate. If the file fills the sample rate recursively halves. This program could be as simple or as complex as you want.
Total component cost less than £2 for a basic hard wired system. Maybe take it up to £5 with boxes and variable resistors for a device that will use different sensors.
Anyone fancy doing it with me? I can draw the circuit idea out in a few mins. Some expert can write the code and I'm not good with a solering iron, but could do it...
===== rgds, Richard Rothwell -------------------------------------------------------------------- GNU and Wine are rirds. Rird is recursively defined.
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