USB type A power cable

If you didn't know before, then you know now that I am a hobbist. I have always dabbled in electronics, soldering, wiring. We used to have RC: Radio controlled cars, helicopter and planes.

Recently I purchased a new BT: bluetooth headset for motorcycle use



I settled on the Camos, aka: IMC-motocom.ca because it is top rated by lots of bike review sites. Camos was the first one to deploy stereo protocol. I was most interested in using GMRS radios for commmunicating with other riders. Most of the riders in Oregon have Chatterbox compatible radios which are better for group use. Most BT units can only communicate with "one other" unit. If you are in a larger group then you need to use standard frequencies, so everyone in the group can hear your communications. The beauty with FRS/GMRS radios is that you can connect an earphone and hear what is going on, even if you can't transmit back.

I did consider the Sena SMH-10 but their BTA: BlueTooth Adapter SR10 is seemingly never available anywhere. Also the fact that I deal locally, directly from Mr Lee who is the Canadian Distributor and lives in Anmore, BC, just a stone's throw from Ioco. I can easily get it exchanged if for some reason it malfuctions



This BT unit is attached by a bracket onto your helmet and is powered by Li-Po (lithium-polymer) batteries which pack a lot of power into a small space, but comes with a stupid 110v battery charger



I am trying to cut down on having a multitude of different battery chargers and I am wondering why they just didn't include a USB cable instead. Notice the specs on the charger label: 5V @ .1 amp . A standard USB can supply 5V @ .5 amp

so last Saturday I ventured to my local electronics parts store and purchased a 3 ft computer cable with USB type A plugs on each end. I also purchased a couple of solder type power plugs and it was hard to find the ones that had a 1.3mm hole in the middle. It seems that IMC/Camos uses a special non-standard plug. The standard comes with a 1.0 mm hole in the centre. This means that the standard plug will not fit the plug on the Camos BT unit as you cannot push it in.



The USB cable was around 3.75 ea and the plugs were 1.85 ea, so for around $8. I could make two of my special cables



I brought out my VOM: volt-ohm-meter, wire stripper and soldering iron and went to work. Firstly I cut the USB cable in half, and stripped the outer coating to reveal the "wires". I got the USB wiring diagram from the internet and discovered that of the 4 terminals, the two outside ones supply the power. Red for positive and Black for negative. I used my VOM and did some continuity checks to confirm



It would appear that these wires are only 28 ga, they don't have to carry a lot of current but you have to be careful when you handle them, as they break easily



It turns out that most power plugs are + positive on the centre pole, and - negative on the outside. I plugged in the factory charger and did a voltage check, and sure enough the centre was positive +5V



The trick to soldering is to get the metal hot enough to melt the solder as your electrical connection will be better. you also need the correct type of solder. I used the electronic type with has a lower melting point. To keep the two terminals apart, I usually put electrical tape between the two joins as sometimes when you twist on the cap they get distorted and touch each other which will ground them out.



Here's a closer look at my custom cable. There is a standard type A, USB plug on one end and a power plug on the other. Here's what the end of my finished cable looks like



I marked the cable with my label machine so I know what it is used for. Before I connected it to my BT Camos unit I did a continuity check to confirm that it was wired correctly, and I also plugged it into a USB power source to recheck the output voltage. I used it to recharge my BT unit, and it works !