Agilent/Keysight Handheld digital multimeter PC connectivity cable by kadakada

Last crawled date: 3 years, 2 months ago

Handheld digital multimeter PC connectivity cable
– For remote control and data logging to PC
– Max. baud rate: 19,200 bits per second
– Compatible with Keysight U1200 Series handheld meters and U1450A/60A Series
PLA plastic,0.1mm layer thickness, printed vertically for better strength of the snaps and better surface finishing.
Used IR LED (D1): 5mm regular IR LED for remote controls
Used phototransistor (Q1): SFH 3310 (not ideal for IR, but that's just what I had)
The PCB inside is prototype board with components to drive the IR LED and phototransistor.
The schematic taken here: http://custom.trengtor.com/lab/usb-mmeter/usb-mmeter.shtml
I used different component values of the original schematics since I used different phototransistor/IR diode:
R1 - 270 Ohm
R2 - 5.1k
R6 - 51 Ohm
I used the transistors I have, but any small signal BJTs will work:
Q2 - BC847C
Q3 - BC857C
The rest components are the same.
Any USB-to-Serial interface chip/board can be used. In my case I used small board with FTDI FT231XQ on it (3.3V version) which was integrated inside the provided housing.
There are two additional 3mm LEDs for TX and RX signal indication. They connected directly to FT231XQ.
Tested at 9600 baud, 19200 baud is not tested.