Daily dabbling

Raspberry Pi I2C dual motor driver

My Raspberry Pi dual motor driver has evolved quite a bit since I last wrote about it. In the original incarnation, I had planned on using the PWM capability straight from the Raspberry Pi to drive the TB6621FNG motor driver. That didn’t work so well due to the fact that […]

Raspberry Pi dual motor driver

This is only sort of a new design. I’ve used this TB6621FNG dual motor driver chip on a number of my boards prior to this one. I basically just took one of my existing boards and shuffled things around a bit to fit the Raspberry Pi Zero form factor. In […]

SImblee Breakout Shield, Part 3

When we last heard from out intrepid Simblee Breakout Shield, it was found to be using and open drain linelevel converter without pull-up resistors, and that’s against the law. Or, at lease against good judgement. After a dual face palm, I found the TXB0108PWR chip, again from Texas Instruments. This one […]

Simblee Breakout Shield, Part 2

I stumbled, and made progress on my Simblee breakout shield. If you didn’t see the first installment, check it out first. Since the first post, I built up a non-shorted board. It seemed mostly okay, except that it gave me 3.9 volts on the 3 volt side, and the same […]

Final Pi Zero LiPoly mod

I solved the final issue with my LiPoly board. It was a minor one. The yellow LED is supposed to indicate whether the LiPoly battery is on or off. It was always on. In a Captain Obvious moment, I discovered that it was always on, because I told it to. […]

Beagle Blues

I’ve been having a lot of fun with my Raspberry Pi boards lately, as I’ve described in a few of my prior posts. With that under my belt, I decided to get out my BeagleBone Black and put it to use. Unfortunately, I did something terrible to it – or […]

Raspberry Pi Zero stack-up

Not stack-up, as in PC board layer stack-up, but add-on board stack-up… The LiPoly board is working fine, as detailed in my prior posts. The USB hub board is also working. The stack shown here has the Pi Zero and both boards. As shown the D+ and D- lines from […]

Raspberry Pi UPS

I built up two more of my Raspberry Pi LiPoly battery back up boards today. After doing so, it occurred to me that, in addition to allowing for portable use of a Raspberry Pi Zero, as I had originally intended, the board, with a few minor modifications, will work quite […]

Pi with my LiPoly board

Pi Zero LiPoly – Final

My Pi Zero LiPoly board was working, but not exactly in the way it’s supposed to. Charging was fine. Powering the Pi from the battery, fine. Th problem came on the net MCP_IN, in the schematic below. I was reading voltage at the test point for MCP_IN, JP4. Either the […]

Pi Zero USB hub

Pi Zero USB

I’m far from the first person to put together a Pi Zero USB hub. In fact, mine is loosely based on the open source design from @richardhawtorn, which was based on the design by @MakerBro. The key difference is that I removed one of the USB A ports in exchange […]