Build a Portable USB Power Device
- Hirose 4-pin Female Panel Mount (Digi-Key #HR213-ND, MFG p/n HR10A7R-4S)
- USB A Jack, Panel Mount or In-Line Pigtail, Red/Black Wires for DC
- Data Wires (Green/White)
- DC/DC Cincon Converter, 9-18V in, 5V out. (Mouser #418-EC4A01H)
- Ceramic Capacitor 0.1uf-50V (Mouser #147-72-104-RC)
- 3amp Diode (Mouser #625-1N5401-E3)
- Optional: LED indicator with 500ohm resistor
- 20-22 Gauge Hookup Wire
On the picture above you can see the wires-
- Ground wire (in black shrink tubing)
- Red/ black wires. Red is positive (+),black is negative (-)
- Green/white wires. Data wires. For some devices they will need to be soldered together, in order to switch the device in charging mode.
The next thing was a enclosure choice; it’s totally up to you. We decided to squeeze everything into the smallest box (on the left). It’s easier to work with the bigger one though…
Here is the complete parts collection. CW from the top: box, DC/DC converter, pigtail USB jack, HIROSE 4-pin panel mount connector, screws. You’ll need a couple more hook-up wires- red and black color (for polarity matching) and 20-22 gauge.
Close-up of the DC/DC converter. This one is from Mouser and takes 9-18V input. Part number is on schematics page. Two ceramic capacitors, wired across the input and output, serve the purpose of extra filtering/reducing interference.
This is how I did the cutout for USB mount. A mechanical part of the project is a little messy and needs some drilling, filing, measuring. The good part is – you are the one to arrange everything according to your needs/taste:
And two holes for mounting screws.
Cutout for HIROSE connector. The little notch on top was filed with a square mini-file.
All wired up, just before the final assembly. A 30 watt soldering iron will do the job. If you’ve never done that- go online and do some search.
That’s it, install the cover, and you’re ready to charge your gadgets!
The pin-out is standard for Hirose – pin 1-Ground(negative-), pin 4-positive(+) After putting it together, we decided to add optional reverse polarity protection (stuff happens…) and visual LED indicator for USB output. Details are on the USB Schematic Page.