Pi Zero + Pimoroni Enviro+ monitoring box

A wall-mounting box for a Raspberry Pi Zero, a Pimoroni Enviro Plus HAT and a PMS5003 particulate matter sensor. 

When the HAT is directly on a Pi, the temperature sensor on the HAT is heavily interfered with by the heat given off by a Pi (even with a Pi Zero W). Code examples Pimoroni provide use some maths to adjust the temperature but I found that the relative humidity reading was way off since this is partially based off temperature and I think is computed in the BME280 itself maybe.

This box solves these issues by separating the HAT physically away from the Pi. They're attached by a 200mm long GPIO ribbon cable. The Pi is in a separate chamber on the opposite side of the box from the temperature sensor, with convection air vents to allowed heat to escape. Since printing my own I've made a couple of adjustments, namely to increase the space for the PMS5003 and fixing a clearance issue for the HAT-to-PMS5003 cable. Fixes are untested though, so no promises that the fit (particularly for the PMS5003) will be perfect!

The Pi Zero is held in with screws to heat-fit threaded inserts, I didn't think there was enough space for nuts to be used. Could possibly tape the Pi in instead if you don't have threaded inserts and screws but the clearance between the GPIO ribbon cable and the wall is pretty close so thick VHB tape may not work. The HAT has four screw holes but two are obstructed by the ribbon cable. The remaining two have screw holes available behind them but I found the HAT friction-fitted in better than I was expecting!

Lastly, the box is quite big so I glued a portrait-orientation postcard onto it with a glue stick for a bit of decoration.

Bill of Materials

• Pi Zero W (non-W or 2 W should both work fine I believe) with headers
• Enviro Plus for Raspberry Pi HAT
• PMS5003 particulate matter sensor
• 200mm GPIO extension cable (male to female)
• 4x M2.5 screws, 5mm long (I think!) and 4x M2.5 threaded inserts, 3.5mm long, 3.5mm outer diameter for the Pi Zero
• 2x M2 screws 5mm long (ish?) and 2x M2 nuts for the HAT
• 2x screws + wall plugs for wall mounting, counter sink with ~7mm wide head

Print off face down (will need some supports, sorry), add the threaded inserts, assemble. I needed a little bit of glue between ribbon cable and body around the folding point to keep the ribbon cable from pushing the box away from the wall. Insert the PMS5003 carefully to avoid damage, can't guarantee the fit. Finally, decorate!