Difference between revisions of "User talk:Mrnuke"

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=== Info ===
=== 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
This is an experimental homebrew design. It does NOT work. 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.
* Photo-transistor and/or diode do not support 9600 baud reliably
 
* The BM857 uses a different wavelength
It is unclear if the IR protocol is a simple UART, or is pulse-width based, or if it uses any other encoding.
* 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 ====
==== Schematic ====
[[File:Bm857_cable_sch.svg]]
[[File:Bm857_cable_sch.svg]]

Revision as of 18:33, 7 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. 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.

It is unclear if the IR protocol is a simple UART, or is pulse-width based, or if it uses any other encoding.

Schematic

Bm857 cable sch.svg

Photos