Robo-Tank 3.0 - Repackaged

[Rob F]

I got some mounting hardware for the controller and a method to mount a cooling fan for a Pi 3 or Pi 4. 

Everything use the same mounting bracket, it's a rail system. Two rails are mounted on the lid and a plate is mounted on the wall, then you can slide the controller on/off the mount. 

If a cooling fan is mounted to the lid the rails are 16.5mm tall vs 2mm if no fan is used. The wall plate is 5mm thick so total additional height is 21.5mm or 7mm. Each rail is mounted using 3 screws, the tall rails have 14mm long screws to keep it very secure, they aren't going nowhere. 

I used a 50mm x 50mm x 10mm fan, my thought was a larger fan could be slowed down to make quite. Here's some numbers. I mounted a DS18B20 temp sensor directly under the Pi so I could get temps where it matters. Like this the fan doesn't directly blow on it. I also used this command to read the core temperature of the Pi. vcgencmd measure_temp

Running a Raspberry Pi 3 the case temperature got up to 41.9c or 107.4f, the core temperature got up to 59.6c or 139.3f. With the 12v fan running full speed the case temperature dropped to 23.6c or 74.5f and the core temperature dropped to 33.2c or 91.8f. The room temperature was about 22.2c or 72f.

I haven't tested with a Pi 4 yet but expect the cooling to be similar. 

This picture is the controller dropping into the bracket, it goes all the way down but positioned like this works as a great stand if you want the controller sitting on a shelf in this position. 





This is the controller slide all the way in bracket. The other 2 extensions looked the same, they have the short rails as a fan isn't required but slide into the same bracket. 



The fan sits directly over the Raspberry Pi.



Fan cable goes through a hole in the lid and can plug directly into the controller.





This pic has the short rails mounted.



Wall plate

Rails



It's standing on the mount and is balanced properly, if you tip it down at the front it wants to go back to flat.