Connecting Pi4 to OSPI board using Rainbow cable

[JTup]

Hello All, 

I have a pi 4 connected to OSPI board with the pins directly plugged into the board. I have a separate power supply going into the pi, as its a pi4 which draws more power and it either doesn't start or I get the lightening (low power) symbol on startup if I don't supply its own power. 

Everything is working well in general, but I'd like to connect the pi via a rainbow cable rather than plug the GPIO pins directly into the board as I've noticed the pi4 gets a bit warm. If I have it via the Rainbow cable I can power a fan on the pi4 to cool it down. 

What I wanted to confirm is:

a) is the list of used GPIO pins here still correct? https://rayshobby.net/docs/ospi14_manual.pdf
b) Assuming if I drop the 2 x 5v ports and the earth, is this likely to cause a problem? As I have a separate power supply going in I don't believe it would, but just checking. 

Many thanks in advance.

Chris

[dan]

Welcome Chris,

a) The pins are still the same.

b) The 5v connections from the OSPi board provide power in to the Pi and should not be used if a separate power source is provided. One of the ground (earth) lines should still be connected in order to make a complete circuit for the other pins.

I have been using a flirc case with Pi 4 with very good results. The case is aluminum and is designed to act as a heat sink so that no fan is required therefor it is silent and uses slightly less power.
https://flirc.tv/more/raspberry-pi-4-case

Dan

[JTup]

Thanks Dan. 

Case looks great. I'd prefer not to have the fan noise also. 

How would you expose the GPIO pins with Flirc case? Do you leave the roof off?

[dan]

Thanks Dan. 

Case looks great. I'd prefer not to have the fan noise also. 

How would you expose the GPIO pins with Flirc case? Do you leave the roof off?

There is a slot in the bottom of the case for the wires to come out. The case has rubber feet that allow room for the wires.

The top of the case has a piece that contacts the top of the Pi's processor chip through a heat conducting pad. That is why the case can act as a heat sink.

[JTup]

I've rewired the pi to Opensprinkler board using a rainbow cable and put the pi in its own case (old one I had, with a fan.) That has reduced the peak temp from 70oC to 55oC! Which is already great. A strategic piece of aluminium foil on the outside of the plastic outdoor weatherproof case has also reduced the temp by another 5oC.

My FLIRC case arrived today also, so I'm going to try that and see if it can keep a similar temp, I think this will be better in the long run as I fear running the fan 24/7 will mean it doesn't last long.

Will report back on findings, thanks for the help Dan.

Chris