Monday, February 11, 2019

PsychoPy on Raspberry Pi

The problem
 
My department is fortunate to have several multi-seat testing rooms for psychological research. The downside is the computers inside them are slightly ageing. They're several-year-old desktop machines with integrated graphics that were originally Windows 7, but have been converted to Windows 10.

Since that conversion, Psychopy, a great open-source experiment generator has been experiencing intermittent issues with graphics-related freezes. It's not all machines, and not all the time, but sporadically they hang for 4-5 seconds before updating the screen. This is bad news for some experiments. Psychopy does not officially support integrated graphics, so our attempts to get this resolved with the developers have so far met with limited success.

Some solutions I didn't go for

1. Upgrade the machines

A £30 discrete graphics card would probably do the trick, but with the number of machines we have across the department, that's still quite a cost overall.

2.  Boot to Linux

We've never been able to replicate this hanging issue on any Linux machine, so it seems Windows specific. Unfortunately, booting from USB is disabled on these machines.


3. Use Linux laptops

Our lab is probably only testing six people at any one time, so we could buy a set of laptops for this purpose and just move them into the testing rooms when we test. This would work, but is potentially a bit expensive (perhaps £2000).

The solution I'm now trying:

4. Use Raspberry Pis

Raspberry Pis are cheap, and the testing rooms already have monitors, keyboards and mice in them (connected to the desktop machines). So, total cost per seat is £51.75. That's for a Raspberry Pi 3, case, power supply, 8GB SD card, official power supply, and HDMI to DVI cable.

The Psychopy programs I've tested so far on this setup work fine.


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