The BASpi-IO is a great little controller which packs a punch. Powering it with the standard 5VDC micro USB wall adapter normally used with the Raspberry Pi may not be an option in some applications. If your application requires powering the BASpi from a 24V source, there are a few solutions out there to help you out.
Searching for a 24V to 5V step down transformer or buck converter on retail websites returns some interesting results. There are several options ranging from $7 – $15. Some will even provide a built-in USB type A or micro USB (standard for Raspberry Pi) output instead of simply giving you 2 wires out. I purchased a few of these to test powering the BASpi with a standard 24V power supply found in most panels. I used my USB meter and DMM to verify the output of these converters. I powered a few BASpi boards using each converter and left them working to test for reliability.
When I received the converters and wired them in to my supply, I was mostly interested in one of the more basic ones which is waterproof, has 2x mounting screw holes, 2 wires to your 24V power supply and gives you a direct micro USB connection to the Raspberry Pi! This unit cost me $7 and it proved to be pretty good. The unit has been powering a BASpi for several months now and has given me no issues. I loved the mounting holes and the direct micro USB output to the Raspberry Pi – very convenient and waterproof! The only drawback being that it can only step down DC/DC so your supply would have to be 24VDC.
Being a tinkerer, I had to look into the other options as well. The more “fancy” converters available provided a 7segment voltage reading display which I thought was pretty cool, so I figured I’d give them a try. I bought 2 versions – one enclosed and one open board. The open board cost me $10 and the encased one was $15.
The open board converter has a screw terminal input for 24V and a USB type A output as well as a 7segment Vin read out and an ON/OFF power switch with LED indication. It does provide 2 small screw holes for mounting (next to screw terminal) but they are not ideal, plus having the USB type A port output means that you’d have to supply your own USB type A to micro USB cable.
The enclosed converter had a lot of extras and it may be overkill but it is cool. It comes in a clear plastic case with a heat sink! It provides a screw terminal for 24V input, a USB type A output and a screw terminal output, adjustable Vout using 2x trim pots, a 7segment display which can show Vin or Vout by using a button to switch, or it can be turned off completely using the second button. It also has several LED indicating 7segment display state and capacitor charge/full states. It has 4 holes for mounting.
Keep an eye out for Contemporary Control’s new Enclosed BASpi series which provides 24VAC/VDC power input, web page configurable universal input channels, and DIN-rail mounting!
Questions and power supply ideas welcomed in the comments section below.