Invasion of the ScratchGPIO Dalek

ScratchGPIO controlled Dalek

The finished Dalek – Blue and Red LEDs with a standard servo

I found a Dalek model in the local recycling centre and, along with a few other items, was able to take it home in return for a few coins. Disassembling it that evening revealed that it was a very elaborate bottle holder, and I’m guessing that the original contents were something like shampoo. Wow… all of that detail for a simple product.

It didn’t take me long to realise that it wouldn’t take long to make this into a simple model that could be controlled by a Raspberry Pi, using a servo for rotating the top half. I also considered moving up and down the antenna stalk, but there wasn’t really enough space to fit the kind of mechanism I had in mind. Overall, I wanted to keep it simple.

I had to do quite a lot of cutting and filing to fit a servo inside, using a small piece of foamed PVC board as a servo mount, along with a custom made “wheel” that fitted the servo horn and the inside of the top.

The electronic interfacing was taken care of by using one of my previously tried and tested buffer boards using a 74HC541 which protects the Raspberry Pi to some extent. I’ve added a standard sized budget servo, two blue LEDs on the head and a red LED on the antenna.

From a software point-of-view, I’m testing using the wonderful “ScratchGPIO”. A couple of scripts are responsible for flashing the LEDs in a menacing manner and a simple loop makes the Dalek rotate back and forth using the Servo7 variable. I like using ScratchGPIO as it gives me a chance to check all of the outputs easily without having to refer back to my syntax cheat sheets. Eventually I’ll probably move the control to Python and use ServoBlaster directly.

Ultimately, this may become an information Dalek. I’m hoping I can get it to pick information out of Twitter, read the news and weather and perhaps announce incoming mail. Watch this space!

I’ve put the second part online now and I’m working on developing the third part of the documentation.

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One response to “Invasion of the ScratchGPIO Dalek

  1. Pingback: Mini amplifier – 5v powered stereo modules | rPi Kitchen

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