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Brymen IR connection protocol - Anyone sniffed it yet?
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jesuscf:
Although I bought the USB Interface Kit to communicate with the BM869s multimeter, I decided to give the information posted in this topic a try and built myself a serial interface adapter using an IR LED and photo transistor together with a C8051F38C micro-controller and FT230 USB to serial adapter.   Attached are some pictures.  Probably the most useful thing I can share is how I made the IR adapter.  I used a few pieces of 1/32 single sided PCB copper clad (very easy to cut with scissors!)  to attach the IR LED (QED123) and photo transistor (QSD124).  The long pins of the LED and photo transistor were bent to add some 'spring' to the adapter for a firm but gentle fit to the BM869s.  Hopefully the roundness and softness of both the LED and photo transistor would prevent any scratches to the adapter window of the BM869s.  Finally, I encased the whole adapter with pieces of PCB to make it more robust.  The PuTTY screen capture shows the response to some of the commands I implemented in my program: '*idn?', 'meas?', 'meas1?', 'meas2?', 'print', Ctrl+c,  'meas?' (after changing the selection to ohms), and 'meas?' (after changing the selection to temperature).

markone:

--- Quote from: jesuscf on February 07, 2016, 05:52:38 pm ---Although I bought the USB Interface Kit to communicate with the BM869s multimeter, I decided to give the information posted in this topic a try and built myself a serial interface adapter using an IR LED and photo transistor together with a C8051F38C micro-controller and FT230 USB to serial adapter.   Attached are some pictures.  Probably the most useful thing I can share is how I made the IR adapter.  I used a few pieces of 1/32 single sided PCB copper clad (very easy to cut with scissors!)  to attach the IR LED (QED123) and photo transistor (QSD124).  The long pins of the LED and photo transistor were bent to add some 'spring' to the adapter for a firm but gentle fit to the BM869s.  Hopefully the roundness and softness of both the LED and photo transistor would prevent any scratches to the adapter window of the BM869s.  Finally, I encased the whole adapter with pieces of PCB to make it more robust.  The PuTTY screen capture shows the response to some of the commands I implemented in my program: '*idn?', 'meas?', 'meas1?', 'meas2?', 'print', Ctrl+c,  'meas?' (after changing the selection to ohms), and 'meas?' (after changing the selection to temperature).

--- End quote ---

Nice job.

I too have the BM869 and it's USB cable (BU-86X) with whom i have a problem :  i'm not able to see it as a COM port under Windows 10.

It's logging program works but it's useless for me, i know that the USB cable has inside a Cypress CY7C63743 and it's supported by SigRok, but i have to write a Labview driver .... |O

jesuscf:
Yesterday night I made another IR adapter for the BM869s multimeter.  I took some pictures of the process, so here they are:

Step01.jpg: I already started when I realized I may as well take some pictures and share them in the eevblog forum.  I am using 1/32" single sided copper clad pcb. 1/16" pcb is too thick for the BM869s.

Step02.jpg: This picture shows the dimensions of the base and the location of the holes for the IR LED and photo transistor. 

Step03.jpg: The holes are 4mm in diameter.

Step04.jpg: I needed to file the base a bit so it fits the BM869s.

Step05.jpg: This picture shows the location of the isolated pads for the IR LED and photo transistor.

Step06.jpg: I used an Xacto knife and small file to create the pads.  It took some time.  Etching may have been faster.

Step07.jpg: This picture shows the IR LED and photo transistor with the leads bent before soldering to the base.

Step08.jpg: The IR LED and photo transistor are soldered to the base.  I use Pb free solder!

Step09.jpg: A four conductor ribbon cable is soldered to each of the pad.

Step10.jpg: Time to make the 'case'.  Let start with the sides.

Step11.jpg: The two sides cut to size.

Step12.jpg: The two sides are soldered to the base.

Step13.jpg: The top is sketched in the pcb.

Step14.jpg: The top is attached with two pieces of wire.  The wires are solder to the top as shown in this picture.

Step15.jpg: The top is soldered to the sides.  Note how I bent the ribbon cable to provide some strain relief.

Step16.jpg: Another view of the almost finished adapter.

Step17.jpg: The adapter was a bit loose in the BM869s, so a couple of drops of solder were added to the sides for a firmer fit.

step18.jpg: The completed adapter in the BM869s.

jesuscf:
In order to make it more accessible, I ported my C program to communicate with the BM869s and decode its output to the Arduino board.  It is my first Arduino program ever... but it apparently works as expected.   I don't think .ino files can be uploaded to the forum  :-//  so I renamed the source code 'bm869s.ino' to 'bm869.ino.c'.  If you want to use it back with the Arduino IDE you have to rename the 'c' file back to just 'ino'.  Also, attached to this post are: a simple circuit diagram, a picture of the connection of the IR adapter (described previously) and the Arduino (using a breadboard), and the output from some commands as displayed in the Arduino IDE terminal.

Note: I arbitrarily selected TX_PIN as pin 12 and RX_PIN as pin 11 in the Arduino board.
jesuscf:
Finally, here is a python script to display the data coming from the BM869s via the Arduino.  Once again I had to rename the file from 'stripchart_BM869s.py' to 'stripchart_BM869s.py.c'.  So before using it don't forget to rename the file so it has the .py extension!  The attached image shows the output of the script.

Note: I already fixed a couple of bugs in the script from the first upload.

Note 2: Added script that works with Python 3.x
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