Display-O-Tron HAT - connecting with power on



This might sound like a basic question, but can you connect the Display-O-Tron HAT to a Raspberry Pi which is already powered on, or will this damage it?

Common sense tells me it would be more sensible to connect it while the power is off but I have a Pi in a “live” environment capturing home energy data that has been up for months that I’d rather keep running if at all possible.



I think the wise recommendation would be to plug it in when the Pi is off.

Electrically I’m not sure there is a high risk of damaging either the HAT or the Pi doing it when the host is live, and I certainly do it all the time, but the risk would ge to align the pins wrongly, say with an offset of 1 pin and supply power to pins linked to the ground.

… note though that if you currently do not have i2c enabled you are going to need to reboot the system anyhow, in which case taking the risk, however minimal in my view to plug your DOT HAT live would not bring you further towards the goal of using it.


Thanks for the reply.

Ah yes, good point about enabling i2c - I forgot about that! So looks like it’s getting rebooted some time soon :-)


Option 3) Buy another Pi ;)

Then network it to your original one to stream the data :D

Okay, okay, not necessarily the most economic answer. As RogueM wisely points out you probably shouldn’t pop it on whilst powered on. Usually it’s fine ( I do it basically every single day, I don’t have time for reboots! ) but it can cause all sorts of problems ranging from misalignment to rebooting your Pi due to a sudden voltage drop causing a “brownout.”