Happy Pi Day! I figured I better post something Raspberry Pi related today…

This weekend I played around with Blog in a Box which was recently released by our Tinker team at Automattic.

A quick and easy way of putting WordPress onto a Raspberry Pi.

BIAB ships with modules to use the Raspberry Pi camera and SenseHAT. I hadn’t used my Pi camera yet and had a fun idea to hack around with.

The camera module allows you to take a photo on a schedule by setting a period of minutes, hours, or days between each photo. I wanted to have a little more fun, so I wired some other electronics up to a Raspberry Pi Zero and wrote a little Python program.

The first electronic element was a simple button. Press it and a picture is taken. Next up was a photocell (light sensor). When the room quickly changes from dark to light, it’ll take a picture. Since the Pi doesn’t have analog inputs, I went with a neat technique of measuring the sensor as a resistor used to ‘fill up’ a capacitor. The last element was an ultrasonic sensor I haven’t used yet either. It measures the distance to an object in front of it, so I’m kind of using it as a motion detector. Walk in front of the sensor and a picture is snapped. Due to mismatched voltages on the PI’s GPIO and the output signal of the rangefinder, I had to use some resistors to create a voltage divider circuit.

To create visual feedback I wired up an LED for each of these 3 components. When one of the components triggers a photo, the associated LED lights up until the process is complete.

I named it Blog in a Box Paparazzi. Of course the code and wiring info are available on GitHub. Should be easy to adjust if you have other sensors, buttons, switches, or whatever you want to trigger photos. Let me know if you try something different.