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  • Author Author: koudelad
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Simplester - a simple cable tester

koudelad

 

 

Introduction

 

I create my own cable sets for various purposes both at work and at home. I agree that crimping and/or soldering your own cable sets is not the most creative thing in hobby/professional electronics, but if there is nothing even close available in your electronics store... you have no other choice.

This project is about a working prototype that is used in a small local manufacturing facility during a rewiring of a few hundreds of OBD extension cables. You might ask, why would anyone manufacture and then rewire the OBD cables in the first place – there are tens or hundreds types available everywhere. This OBD extension cable is forked for diagnostics purposes, so it it not a pure cable extension. One end is plugged into a car, the other end is plugged into a OBD dongle / diagnostics etc. and the forked part leads to a custom diagnostic device (a CAN message logger).

 

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I was put in front of this task, because we didn’t want to throw away hundreds of cables that were missing a few wires in the 1:1 extension part from the original manufacturing. I also hate creating more electronic waste. (It could have been repaired by the original manufacturer, but a container to China both ways would delay the delivery by 2 months or more.) So there is a new contract manufacturer that will get the cables, the missing wires, fit them and then test the proper connection. What would you do if you had to build the test device in just one day?

 

BOM and the schematics

I didn’t want (and have time) to build a device using a microcontroller, so I chose a ready made UTP cable tester. These testers are made for 8 wires cables and OBD II connector has 16 wires, so I needed two of them.

 

  • 2 pieces: noname UTP cable tester
  • 1 piece: OBD II connector
  • 1 piece: OBD II plug
  • 2 pieces: OBD II connector housing
  • 2 pieces: 1 meter ready made straight UTP cable

 

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Prototype

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Proof of work

 

Conclusion

 

Maybe you have already used this idea in the past, but I just wanted to post this simple project to remind myself not to reinvent the wheel every-time I need to accomplish something.

What do you think? How would you build such a tester? Do you want to see more (the DIY CAN message logger)?

 

Thank you for reading and watching.

 

David

 

  • in reply to shabaz

    Thanks, Shabaz.

     

    One of my coworkers is a musician. I clearly remember him going to work with about 5 pieces of 10 meter long cables to work, saying he needs to check them. I think these were coaxial cables with 3 pin XLR connectors on their ends. On the first try, he did exactly what you described using a DMM. The trouble is, the discontinuity was sometimes measurable only with a specific cable bend, so he had to hold the two ends (then somehow grabbed them with mini alligator clips?) and went through all the cable, bending it various ways. When he found a broken part, he cut it there ( plus a few centimeters on each side) and fitted a new XLR connector.

    In the afternoon, he was leaving work with 15 cables of various length, instead of the original 5 image

     

    This tester has the advantage, that is tests multiple wires at the same time, but is has no buzzing (which is great that you can hear the sound and bend the cable to test it at the same time), so you have to look at it to confirm the wiring. However for fixed cables or new assemblies as above, it can be very useful.

  • Hi David,

     

    Neat trick to use the UTP cable tester! Clever idea to create the custom UTP patch cables for adapting it to meet your needs. I will suggest this to a friend who works a lot with audio wiring, in case he ever needs to buzz-out cables, saves having to hold plugs and multimeter leads with just two hands : )

  • Thanks David,

     

    Great Demo of a cable tester.

     

    John