0
\$\begingroup\$

I would like to convert the usb output of a scale to a serial format so I can read it through a com port.
I saw this tutorial from adafruit Adafruit serial scale but that scale is not available anymore and scales with serial output tend to be expensive. I would like to take DYMO 10 LB and attach the usb port on it to a USB to serial and then attach this serial output to a serial to usb converter. Then I will have a COM port and I can read the data through a serial monitor. The question is will I be able to read the data coming out of this and interpret it as a weight?
And if not, how hard will it be to write my own driver to read data coming from the scale?

\$\endgroup\$
  • \$\begingroup\$ Have you considered probing it in case there already is a UART signal available? \$\endgroup\$ – Ignacio Vazquez-Abrams Jan 12 '16 at 23:24
  • \$\begingroup\$ I haven't purchased it yet. What do you mean by probing it? \$\endgroup\$ – ben Jan 13 '16 at 0:05
  • \$\begingroup\$ You want to convert USB to serial to USB? Eh? You can't just convert USB to serial, you need a USB host with the correct drivers for the device type. \$\endgroup\$ – uint128_t Jan 13 '16 at 0:12
3
\$\begingroup\$

It is not a straight forward usb-cdc/virtual com port. The Scale uses a USB-HID slave/peripheral controller. This needs to be read using USB-HID. It is completely different from USB-CDC, a.k.a. a usb virtual com port. It does not use a USB to RS232/TTL adapter.

See http://steventsnyder.com/reading-a-dymo-usb-scale-using-python/ and https://stackoverflow.com/questions/1275974/program-for-hid-usb-scale and https://www.youtube.com/watch?v=srvtDNYR05U

Also, your idea of using a USB to Serial cable will not work that way. A USB to RS232 cable is not bi-directional. It can not be used in reverse. It will not connect to a USB peripheral/slave. It has to be connected to a USB host/master, like a computer.

\$\endgroup\$
  • \$\begingroup\$ This is a very good answer; concise, helpful, reasonably complete, links to useful information (which was new to me) and includes a link to an existing near-duplicate ee.se answer! Bravo, sir. Did you mean to say "It does not use a USB to RS232/TTL adapter."? That sentence seems unnecessary, or am I missing the point? \$\endgroup\$ – gbulmer Jan 13 '16 at 1:29
  • \$\begingroup\$ @gbulmer some devices that were originally designed for serial, were upgraded to usb, by using a usb to serial adapter inside. The manufacturer could change little in manufacturing or software, but still get the usb "feature". So sometimes all you need to do to get serial access is to connect between the adapter and the serial signal. \$\endgroup\$ – Passerby Jan 13 '16 at 2:04
  • \$\begingroup\$ Ah, ha! I get it. \$\endgroup\$ – gbulmer Jan 13 '16 at 2:06
0
\$\begingroup\$

To communicate with my Dymo scale I have used the software BillRedirect from BillProduction company ... This software communicate directly with my Dymmo scale USB and redirect the weight to my software... I use the Wedge Keyboard option but according the documentation this software can create a virtual com port that any software can use.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.