Servoblaster – a daemon for driving servos from the Raspberry Pi.

Well… I tried a serial to servo controller which worked fine, but required nearly a second between commands (0.88 seconds to be precise) and didn’t maintain the pulses for any longer than that time. It was okay as a proof of concept, but no good for controlling servo speed from my Python program. The alternative was to download and install ServoBlaster.

I did damage one Raspberry Pi by connecting the servo straight to the outputs. Not sure what the problem was as I was being careful. It seemed better economy to create a buffer board.

This buffer board safely interfaces between the Raspberry Pi and up to eight servos. It can also be used to drive LEDs if they are wired correctly.

This buffer board safely interfaces between the Raspberry Pi and up to eight servos. It can also be used to drive LEDs if they are wired correctly.

The buffer board is single sided and uses a 74LS245. I’m being a bit lazy as the ‘245 is intended to be a bi-directional tristate buffer and I’m forcing it to work in one direction. The advantage with this is that the inputs and outputs are pretty much in line. I can minimise the number of links required and ensure that only a single-sided board is needed. An alternative might be the 74HC541, but I didn’t have these and I’d have to re-design the board. Maybe another day…

Servoblaster Board

The files for the buffer board are at the bottom of this post.

Here are the files for the buffer board. It uses a 26 way connector for GPIO, a bunch of 3-way connectors for the servos, 74LS245 octal buffer, 7805 regulator and a couple capacitors to keep the power supply happy.

Circuit Wizard – ServoblasterInterface- Normal Circuit Wizard – ServoblasterInterface-artwork Circuit Wizard – ServoblasterInterface-proto

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