Lab tip for power connectors

Hi there! Today I’ll show you a simple but very useful tip for your hacking sessions in your home lab or local maker/hackerspace.
Probably sometimes you want to power some device from your laptop’s USB or phone charger, but the device has a DC barrel power connector and there you go and make a USB A to DC barrel connector. Then, in some other day you actually need the same thing but with a micro USB, or a mini USB, or a USB B, or a thinner barrel connector, or a larger connector, or alligator clips, or a longer cable, or a shorter one, and so on… The problem is that after some time you’ll end up with lots of connector converter cables and you’ll still find yourself needing a different connector converter cable. Well, I’m going to share with you a simple solution to avoid making lots and lots of cables.

rca connectors and cables for multiple cables

I’ve learned this solution during my 1-year stay at the Signal Processing Laboratory of the University of the Algarve as an R&D engineer. The trick is to always have a common connector in every cable that you do, which can be of several types, such as BNC, RCA or others. Besides the connectors you will also need to have the junction connectors.

If you look at the images you’ll see an example using RCA connectors and RCA junctions to make a cable to convert a USB A connector to a DC barrel connector.
To do it you would have to do the following steps:
 
  1. Cut a cable containing a USB A connector on one end;
  2. Solder a male RCA connector to the VDD and GND wires of the cable with the USB A connector. As a rule, always put the VDD in the middle pin and the GND on the outside;
  3. Get the cable with the barrel connector and solder a male RCA connector to the other end. Once again, VDD in the center pin and GND in the outside;
  4. Now that you have both cables with RCA endings, you can connect them using a Female to Female RCA junction.
I normally use RCA connectors since they’re cheaper than BNC connectors. However, BNC connectors are more robust and provide a more solid connection. You can get any of them from ebay at good prices if you buy them in packs.

rca_connectors_and_cables.jpgusb_a_cable_tip.jpgremove_insulation_usb_cable.jpgrca_cable_solder.jpgrca_connector_soldering_usb_a_cable.jpgremove_insulation_cable.jpgrca_connector_soldering_barrel_cable.jpgcable_conversion_ready.jpg
If you always do this to all the leftover cables that you can get, you’ll be able to do any cable to power your devices in no time, since you’ll only have to unplug one end and connect it to another cable 🙂 . This way, you won’t have to make a new cable for every single combination of connectors that you can imagine. If you want, you can also use two junctions and put an extension cable in middle 🙂 .
I hope this trick will be useful for you 😉 
 
Take care!
 

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