Difference between revisions of "User talk:Mrnuke"
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* The value of the photo transistor pull-up resistor is too high (too sensitive) or too low (not sensitive enough) | * The value of the photo transistor pull-up resistor is too high (too sensitive) or too low (not sensitive enough) | ||
The manufacturer's cable contains a PIC microcontroller that communicates with the PC, and multimeter. The data sent through the serial port is not what the DMM receives/sends. Any straight cable will not work. | |||
TODO | TODO | ||
==== Schematic ==== | ==== Schematic ==== | ||
Revision as of 05:50, 5 December 2012
BM857 PC interface cable
I'm trying to build a PC interface cable for my Brymen BM857. I have used Radioshack 276-142 IR diode and photo-transistor set, and a PL2303 USB to serial converter.
If you have a real cable you'd like to donate, hop on to #sigrok and contact me.
Info
This is an experimental homebrew design. It does NOT work. It is yet unclear which of the following reasons, if any is the cause
- Photo-transistor and/or diode do not support 9600 baud reliably
- The BM857 uses a different wavelength
- The value of the photo transistor pull-up resistor is too high (too sensitive) or too low (not sensitive enough)
The manufacturer's cable contains a PIC microcontroller that communicates with the PC, and multimeter. The data sent through the serial port is not what the DMM receives/sends. Any straight cable will not work. TODO
Schematic
Photos
The IR diode and phototransistor are prominent on the board
Board being held in place by the rubber holster
