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Homemade Radio Electronics
ADC 6ch analog signal measurement and logger and wireless link with real time PC show all
this ADC logger system can measure up to 6 analog signals at the SAME time and transfer it via several serial ports to PC's or loggers/recorders
The SAMPLE speed is 200Hz and 20Hz at the same time
The BAUD rates are 115200 and 9600 send out at the same time
all serial ports use seperate MAX232 drivers and both ADC sample systems use 100% seperate microcontrollers.
Each ADC count is 4.905mV, the 10 bit analog values are limited to 999 max (not 1023 as normal) this saved byte x 6
makes it possible to update all 6 channels with 20Hz and 200Hz using 9600 and 115200 baud.
The 6 XLR connectors uses the normal GROUND at pin 1, so microphone cables easily available can be used
pin 2 are battery power 18V in this case, pin 3 is the analog signal 0 to 4.9V, loading is 100k ohm.
The data send to the PC look like this:
406,377,484,496,000,000 405,376,483,495,000,000 405,376,483,495,000,000 405,376,483,495,000,000 405,376,483,495,000,000 405,376,483,495,000,000 405,376,483,495,000,000 405,376,483,495,000,000simply use a terminal program like COM76 or others with capture to file option.
The wireless receiver is connected to a PC with a USB FTDI232R, and the receiver is powered from the USB,
its details are too trivial to be mentioned here
The wireless link have a range of several km due to its 500mW power and super sensitive receiver
This system was specially made for rocket booster measurements, look at http://www.copenhagensuborbitals.com/ for more information
The realtime show all values on a PC is done using a HP VEE program
it is easy to calibrate and change meter readouts on the fly
this program also perform logging in raw data and fully calibrated values from a good safe distance from the test object.
March 5th 2009, oz2cpu Thomas Scherrer