ribbon cable tester

Discussion in 'The Projects Forum' started by stevy123, Dec 5, 2008.

  1. stevy123

    Thread Starter Active Member

    Nov 19, 2007
    Hi All

    Just wondering has anyone on here made a device to test ribbon cables? Im trying to test ribbon cables to ensure that they are crimped the correct way round when they go into the housing.

    i was thinking of using leds as the indicator and when the correct connection is put in the led lights up. How can i do this? As if the cable is connected the wrong way round the led will still light up as there will be a connection from another wire.

    thanks in advance for any help.
  2. leftyretro

    Active Member

    Nov 25, 2008
    Well a comprehensive automatic tester would generate a signal on each unique pin on one end and scan all the pins on the other end and expect to see the signal on the one matching pin and on none of the others. It would then have to step to the next pin and repeat the scan. It's a basic scan for open and shorted paths. Lather, rense, repeat..

    I worked a lot with ribbon cables in past decades, both making up cables and using them. They are pretty reliable if you use the proper connector presses and good quality connectors. Easiest screw up is to crimp the connector such that pin one doesn't match up with pin one. Been there done that.
  3. bertus


    Apr 5, 2008

    You could make a circuit like an 4017.
    On one end the 4017, on the other end the leds.
    With the direction the leds go you can see if the connections are right.
    When there are leds missing, you can see if there is a connection missing.

  4. mik3

    Senior Member

    Feb 4, 2008
    In my opinion, the best way to test cables is to see if they conduct current and not only measure the voltage at the end. Sometimes wires are fairly conduting (high resistance) but you still can measure voltage a its end because voltmeters have high input impedance. However, if you connect a led to the wire which it is fairly conducting the led won't light due to the high resistance of the bad connection. Thus Bertus suggestion to use a 4017 decade counter to test each wire of a ribbon cable individually is nice.