MMDVM + pi4b - heat issues?

General support for the Pi-Star System
G4SJP
Posts: 6
Joined: Tue May 18, 2021 5:59 pm

MMDVM + pi4b - heat issues?

Post by G4SJP »

I have had the pi4b for some time now. I am just about to receive a MMDVM hotspot board from eBay.

My question; if the hotspot fits where my fan currently resides, how do I cool the pi4b? Perhaps I don't need to?

I'm wondering if I should be getting a pi zero w instead?

Apologies for what is probably a very naive question!

Thanks, Stephen G4SJP
n9mxq
Posts: 236
Joined: Sun Apr 29, 2018 12:12 pm

Re: MMDVM + pi4b - heat issues?

Post by n9mxq »

I'm running a 4b on my new Dstar duplex hotspot. It idles at about 57c. I've 3d printed this case (https://www.thingiverse.com/thing:4611538) and am waiting on a couple more parts to put it together. I'm hoping it will cool the 4b down just a touch. But, I've seen no loss of performance with it as it is.
Gene in Belvidere IL
Please don't email me with questions.
That's what these forums are for.
There's much more brainpower collected here
than I have alone.
G4SJP
Posts: 6
Joined: Tue May 18, 2021 5:59 pm

Re: MMDVM + pi4b - heat issues?

Post by G4SJP »

Thanks Gene,

That sounds encouraging. Mine's running at 38.4C with the fan on. I've just disconnected it and I'll see how high it goes.

73 Stephen G4SJP
n9mxq
Posts: 236
Joined: Sun Apr 29, 2018 12:12 pm

Re: MMDVM + pi4b - heat issues?

Post by n9mxq »

Got all the pieces put together and now, at idle, I'm sitting around 38.5c.. Much better. Will have to keep an eye on it when traffic picks up and see what happens.
Gene in Belvidere IL
Please don't email me with questions.
That's what these forums are for.
There's much more brainpower collected here
than I have alone.
n9mxq
Posts: 236
Joined: Sun Apr 29, 2018 12:12 pm

Re: MMDVM + pi4b - heat issues?

Post by n9mxq »

Couple guys have been ragchewing for about 35 minutes. Highest observed temp is 38.9c.. I'll take that improvement.
Gene in Belvidere IL
Please don't email me with questions.
That's what these forums are for.
There's much more brainpower collected here
than I have alone.
G4SJP
Posts: 6
Joined: Tue May 18, 2021 5:59 pm

Re: MMDVM + pi4b - heat issues?

Post by G4SJP »

Thanks all!

As you might see from the other thread I started, I'm beginning to think that I'd be better off with a zero. It fits the hardware which came with the MMDVM and is not an expensive option!

I didn't buy the Pi 4b for this application anyway, it was just a solution looking for a problem and I thought it would be fun!

Most grateful for the advice,

73 Stephen
G6WOV
Posts: 27
Joined: Thu May 13, 2021 12:47 pm

Re: MMDVM + pi4b - heat issues?

Post by G6WOV »

On Idle, my Pi 4 is hovering around 50 - 54C. So I have just bought a pack of 4 Heatsinks, a Standoff Header, and a small Fan. I'll make a note of what the Temperature is when the Heatsinks are fitted. Then I'll see what the Fan does to the Temperature. I'll also see if the Fan is quiet?

It said that it could be connected for Continuous Running, or "Quiet Cooling Mode" depending on which GPIO Pin the +ve is wired to. Has the Pi-star setup got a provision for the Fan Speed Control, or is it just a case of selecting a GPIO Pin in the Pi's Configuration to control the Fan? Which GPIO Pin is generally used for the Cooling Fan on a Pi 4 for Pi-star, or should one be agreed upon in advance by everyone so it will not conflict with any "future modifications"...
CT2HRB
Posts: 19
Joined: Thu Apr 26, 2018 8:15 pm

Re: MMDVM + pi4b - heat issues?

Post by CT2HRB »

I have two hotspots, one is MMDVM_HS on a RPi2 and the other is DVMEGA on a RPi2+ (AFAIK similar CPU to RPi3 but without WIFI), both also average always 45-50ºC at idle (usually always 50ºC at summer), and the MMDVM_HS runs like this 24/7 for 3 years now without any problem...
G6WOV
Posts: 27
Joined: Thu May 13, 2021 12:47 pm

Re: MMDVM + pi4b - heat issues?

Post by G6WOV »

Thank you for your reply.

I have fitted the 4 Heatsinks to the Pi 4, and now the nominal Temperature is about 54 C and hovers between 53 and 56 C. Which is higher than without the Heatsinks when Idle, I'm not sure why that should be?

But I think I will connect the Fan directly to 5V and GND, and not worry about it being Controlled. The Header Pins were to allow the Pi 4 and the Duplex Hat to be spaced apart, plus also to connect the Fan to the Long Pins and not the Boards. The Fan is a 4010 which I will mount on the side so that it blows the air into the gap between the two Boards. Or should it "suck" the hot air away from the Boards? I will check the Idle Temperature again when fitted. The Boards are mounted in a 5 Slice Case so it has lots of gaps for air to flow.

The Duplex Hat is one fitted with a 0.96 OLED, but I would like to add a Nextion so that I can experiment with one of those too. I'll 3D print a box to put it all in later when I get to that stage, so that might decide which way the Fan will blow (in or out). Or whether two fans would be a choice; one in and one out. But until I start using it with a Radio, and how long it is used concurrently for, will need to be evaluated.

I am sure that many have already experimented with all these matters and more, and the answers are already out there, but it is all new and interesting to me. As it is for us all.
G6WOV
Posts: 27
Joined: Thu May 13, 2021 12:47 pm

Re: MMDVM + pi4b - heat issues?

Post by G6WOV »

I looked at buying the Aluminium Dual Fan Heatsink but thought that it would get in the way of the Hat on top. So I just got the individual Heatsinks and Fan with a Slice Case, plus a Header to extend the Pins and put a gap between the two boards.

I've been reading up on previous Posts since joining and enjoying my "steep learning curve". Everything is new to me; Hotspots, Digital Radios, Raspberry Pi's. I know what they are, just never used any of them. Also I am not up on Social Media at all, so not even sure how to quote someone else's comment to write "G6WOV: etc". So I must appear a total novice?

I will find out how to view the Throttled Index and see if there are any Counts in it. It's the not knowing what is normal? I only discovered yesterday that I can SSH directly to my Hotspot from the Dasboard browser. I assume that's where I type the "vcgencmd get_throttled" Command.

So I am telling myself what I say to the Apprentices; "If in doubt ask", "you are probably not the only one who doesn't know!"

Thank you again for your help.

73s Keith
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