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Homemade Radio Electronics
Atmel Mega32 8ch Analog signal measure logger

this logger can measure up to 8 analog signals at the SAME time and transfer it via serial port to a PC
The SAMPLE speed can be changed from 200Hz (all switches off) - 100Hz - 10Hz - 1Hz
The BAUD rate can be changed from 230k4 (all switches off) - 115200 - 57600 - 19200 - 9600 - 4800
it is clear you cant combine too fast sample speed with too slow baud rate.
for 200Hz sample, use 115200 or up
for 100Hz sample, use 57600 or up
for 10Hz sample, use 19200 or up
for 1Hz sample, use any baud rate and up

The construction is quite simple, will only take a few hrs to solder.

I used some of the components as SMD but it is not critical.
I suggest you use a MEGA32-16PC, not the 32L-8PC as pictured here !

mount the decoupling caps and crystal as close to the IC as possible

A fast handdrawn schematic so you get the idea.

the Atmel AVR Mega32 pinout

if you like try the HEX file here: m32-adc-logger.hex
external osc, no divide.

for the serial to PC connection you can use a MAX232 or USB FTDI232R, it is too trivial to be mentioned here

the data send to the PC will look like this:

simply use a terminal program like COM76 or others with capture to file option.
then excel or other spreadcheet programs can turn the data values into nice colored curves,
scale and math the values to show temperature, pressure, speed, voltage, current, depending on the sensors or transducers used.

here is an example of measurements using excel, a temperature regulator to melt lead.
interesting to see the extra power needed to go tru the melting point at 327.46C
and see the 400C setpoint regulation overshoot and swingin

this project and hex file can be used free of charge for any home and private usage
for any commercial usage please contact me first !

13th of November. 2008