4
\$\begingroup\$

I just ordered an Fingerprint sensor I followed the schematics and made it work with my Arduino.Now I want to connect it directly to my computer, the device has ( GND, RX, TX, 5V ) I have a prolific USB cable witch has outputs (RX,TX,GND) .

Is it possible to connect the USB Prolific cable with the device ?

I know that USB outputs 5V but how can I get power if the prolific cable does not have such output?

\$\endgroup\$
4
  • \$\begingroup\$ If it is basic UART ... I guess it should work just fine. You'll need some device driver that can open the virtual serial port and make sense of the data. \$\endgroup\$
    – jippie
    Jan 5 '13 at 23:13
  • \$\begingroup\$ @jippie how I connect the wires ? \$\endgroup\$
    – opc0de
    Jan 5 '13 at 23:13
  • \$\begingroup\$ Oh wait, you don't have a +5V on your cable? There are really cheap USB-UART interfaces that can do just that. Other than that, RX/TX may need to be crossed. Here is a random link from a random search engine on a random shopping site: ebay.com/itm/… \$\endgroup\$
    – jippie
    Jan 5 '13 at 23:14
  • \$\begingroup\$ I would recommend using an FTDI usb to serial converter cable or board instead of a generic one from ebay. \$\endgroup\$ Jan 5 '13 at 23:32
2
\$\begingroup\$

If I understand correctly, you are using a USB to serial cable to connect your fingerprint sensor to the PC.
If the cable is using the +5V USB (PC side) supply (to drive it's MAX232/FTDI IC or whatever it's using), then for it to receive data from the sensor, it only needs the TX/RX and ground anyway, so it should work just fine as long as the two have a common ground (i.e. the cable ground and sensor ground are connected)

If I have misunderstood things, it would help if you could provide a link to your cable/datasheet.

\$\endgroup\$
2
  • \$\begingroup\$ Thanks for your response Oli. So you say if I connect GND of the cable to GND of sensor then it should work without powering 5V the sensor ? \$\endgroup\$
    – opc0de
    Jan 6 '13 at 9:44
  • \$\begingroup\$ I'm not 100% since I don't know exactly which cable it is, but yes, I'm pretty certain it will work okay. It certainly won't do any damage to connect up and try anyway. If it doesn't work, let us know and we can look again \$\endgroup\$
    – Oli Glaser
    Jan 7 '13 at 10:38

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.