I do ant keeping and need to keep my ant testubes at consistent warm temperatures.
I'm not sure how the 5v pins work on the raspi and how many 5v components I can attach if someone can point me in the right direction. I've not have much luck doing my own research.
Let me know if this reddit post is viewable with its links detailing the parts I'm ordering.
https://www.reddit.com/r/raspberry_pi/comments/1clejt4/trying_to_make_a_climate_controlled_box_will/
oops.se
Different Raspberry Pi versions (and you haven't stated your version) can provide power that way, but I don't recommend it.
astrydax
Sorry yeah, in the post on reddit I have a pico and a waveshare2040
oops.se
Then its like 40mA or so
astrydax
So the pi itself would just need to power a temp sensor, a screen, and fan.
The heater would have its own source controlled by a relay
oops.se
And?
oops.se
If you state no facts, it is impossible to assist you!
astrydax
Im sorry I thought those were relevant facts. I'm not sure what facts you're looking for.
I was under the impression that those 3 components I mentioned wouldn't draw too much current. I see that the fan draws about 150milliamps.
What I really don't understand is how people connect multiple components that need to draw from 5v on the pi when there is only 1 or 2 pins that are marked 5v.
thunder07337
Breadboard
thunder07337
riothedev
breadboard or a custom pcb, although i don't suggest plugging a fan and a screen together just in case, so u could just have a seperate power source or a shared power source with the pico
riothedev
u can draw a maximum of around 300ma from it in total
riothedev
but even so i suggest letting the pico do the thinking and get another source for the power
astrydax
Would I be able to put both the heater and the fan on the other end of the relay?
I have a 12v power for the heater, I'm just not sure how I would also connect the fan. I could get 12v fans.
riothedev
no need u could just step down the 12v to 5v
riothedev
im kinda confused though
riothedev
putting the fan on the same relay as the heater
riothedev
then u'd be turning on both at the same time no?
riothedev
so from what i see u'll need a 12v relay for the heater, a 5v relay for the fan and screens can usually be connected straight to the pico <@237258018348204032>
riothedev
the pico has a built in temperature sensor but i dont know how accurate it is, so u could get something like an LM35
riothedev
it has 1c accuracy so it wont be accurate down to the decimals so i dont know if its fitable for u
riothedev
but that can be connected to the pico itself as well
astrydax
I didn't know it had a sensor. That's usefully. Ok so I could do two relays. The fan is to circulate the heat for even heating so I suppose it would be ok if it only came on when the heater did.
I was going to put a temp sensor at the bottom and top of the box to make sure the temperature isnt a gradient in the enclosure.
Running three power sources to the box for two relays and a pi seems like a lot though.
riothedev
ah i thought the fan was to cool things down or something so then if u only need it to turn on while the heaters on then u can just step down the 12v to 5v for the fans
riothedev
also u dont need to run 3 different power sources to the box
I don't mind getting extra at that price. I'm going to be making a few of these boxes.
I've got different species of ants that will want different temperatures
riothedev
u should search around locally, there tend to be some electronic components shops that sell boards such as that
astrydax
So I'll need a few enclosure
riothedev
before buying them i suggest making a schematic or something os u know exactly what u'll be making
astrydax
I'll work on that then first
riothedev
wait
riothedev
<@237258018348204032> I was thinking something like this
astrydax
Oh sweet yeah that looks good. That's awesome thanks for making that.
riothedev
ure welcome, although im not an expert or anything so i'd have someone else look over it just in case if it could be any better
astrydax
Oh you know what. I think the buck converter might distrub the ants with EMI. I'll have to look into that too.
riothedev
good idea
riothedev
<@237258018348204032> kinda curious, did u figure anything out?
I think I will edit the schematic to have two buck converters instead of two relays however and just power the fan off the same relay as the heater
riothedev
oh thats pretty cool
riothedev
yea i was thinking that too just thought it'd be cheaper to have two relays instead of two buck converters
astrydax
I struggled quite a bit writing the driver for the aht21 temp sensor and for some reason I'm getting responses saying the temp in the thousands with the correct temp sprinkled in every so often. I just filtered out any response over 230f but I'd like to know what's causing that to happen
riothedev
thats weird, are u using a library to read the temp?
astrydax
I tried one I found on GitHub but it wasn't working for some reason, doesn't seem to be a lot of stuff out there for this sensor. But it's way more affordable than everything else I've seen more commonly used
looks like the stepdwon convertors i ordered are either faulty or i'm using them wrong. They didn't have the best reviews.
Is there one you suggest using? This is what I tried https://www.amazon.com/dp/B08JZ5FVLC
astrydax
video
riothedev
thats rly nice
astrydax
Any idea about getting this boy to work on the pico?
It's SPI but doesn't have a CS pin and is kinda labeled like i2c?