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Is my Raspberry Pi 3 B+ okay?

PostPosted: Sat Dec 08, 2018 11:32 am
by Lion_Jayson
I bought this raspberry pi 3 b+ from cytron during the 10.10 promotion. Currently i been using it to do a project which involves a rotary encoder B106U. I been using it with VNC viewer via LAN cable and the PI is connected to a circuit with pull up resistor (2.2k) for OUTA and OUTB of my rotary encoder. So the problem here is, my PI is getting very hot once i boot it, is it okay or not? Cause i still need to add two more rotary encoder to it and i scare the Pi will overheat and damaged. I'm still new with Raspberry Pi.
Thanks in advance.

Re: Is my Raspberry Pi 3 B+ okay?

PostPosted: Mon Dec 10, 2018 11:49 am
by ober
Good that you ask :)

Raspberry Pi itself will get warm during normal operation, but hot or warm is quite subjective.
So it will be good if you could:
1. Share a few photos of actual hardware setup.
2. What is the supply voltage to encoder and where is this voltage coming from?
3. Where is the pull up of 2.2K ohm resistor being pulled to?
4. Anything beside the encoder being connected to the Raspberry Pi?
5. What if you remove the encoder from Raspberry Pi? Will it get warm/hot when it boot up?

Re: Is my Raspberry Pi 3 B+ okay?

PostPosted: Tue Dec 11, 2018 12:36 pm
by Lion_Jayson
First of all, thanks for the reply.

Extra add-on : The part that get very hot is the chip near the USB cable port. The chip in the middle also get hot.

Okay, this is the photo of the hardware setup.
1. The image is here https://imgur.com/a/QsU5WDX
2. The supply voltage is from AC/DC adapter from cytron.
3. First time approach pull up resistor these, so i don't really know the function, i just follow connection in the user manual of the b106 rotary encoder.
4. Nope
5. The only connection is the lan cable and it getting hot even in idle.

Re: Is my Raspberry Pi 3 B+ okay?

PostPosted: Tue Dec 11, 2018 4:07 pm
by ober
OK, thanks.
1. From the photos, it seem you are using 5V from Raspberry Pi GPIO, and the pull up resistor is connected to 5V too? Because I did not see any jumper wires taking 3.3V from the GPIO. The pull up resistor should be 3.3V because Raspberry Pi GPIO is 3.3V logic, not 5V, right?
2. OK, should be fine.
3. So this is answered in no.1, it should be 3.3V.
4. OK
5. What happen if you remove all the jumper wires? Do not connect anything.
6. Actually the IC beside USB is USB and network hub. If no USB or LAN usage, it should not get hot.

Re: Is my Raspberry Pi 3 B+ okay?

PostPosted: Tue Dec 11, 2018 8:02 pm
by Lion_Jayson
1. Yes, i use the 5V from the Raspberry Pi GPIO, the resistor also connected to 5v. I use the 5V only. So should i change the resistor to 3.3V?
My connection is GPIO supply 5V to the resistor on one end, the other end of the resistor is the encoder output and return the GPIO Input pin. The only ground i use is the encoder ground to the Ground GPIO pin.

5. I remove all the jumper wire, just the power to boot Pi and LAN cable connect to laptop with VNC viewer.
6. I'm using the LAN and close the WIFI unit, still it will get hot but at a slower rate
7. Will it be my coding problem?
8. 1 more question, i don't understand the pull up resistor stuff. If i got a physical pull-up resistor, my coding requires the pull-up resistor at GPIO.setup (pin_A, GPIO.IN, pull_up_down=GPIO.PUD_UP)? Cause i didn't put it.
Thanks

Re: Is my Raspberry Pi 3 B+ okay?

PostPosted: Wed Dec 12, 2018 6:35 am
by ober
1. In that case, you need to change that, pull up to 3.3V since the Raspberry Pi IO logic is 3.3V only. Frankly, I am not sure whether the GPIO survive your 5V logic (as you pull up to 5V).

Well, since you remove the jumpers and everything else, it still get warm, that is normal warm.

Is fine to not understand everything, you can always search for it. Try searching open drain output, NPN output and understand it.

Re: Is my Raspberry Pi 3 B+ okay?

PostPosted: Wed Dec 12, 2018 9:10 am
by Lion_Jayson
So what you meant is the 3.3V supply to pull resistor? and the 5v only to the encoder? My connection based on the user manual https://drive.google.com/file/d/1AayZIf ... 3n-Bm/view connection.
Should i put a fan to blow it all the time?
alright i will look into it.

Re: Is my Raspberry Pi 3 B+ okay?

PostPosted: Wed Dec 12, 2018 10:19 am
by ober
Yes, you refer to the User's Manual correctly, but you did not read it thoroughly :)

The output of rotary encoder is open collector (NPN) type; a pull-up resistor to high state of logic voltage is required. As an example, if PIC MCU is used and the logic voltage is 5V and 0V, thus user need to pull the output of rotary encoder with a 1K to 10K resistor to 5V.


As mentioned, a pull-up resistor to high state of logic voltage. The example show connection of PIC which is 5V powered, but Raspberry Pi is 3.3V GPIO, so you should pull up to 3.3V, not 5V.

Re: Is my Raspberry Pi 3 B+ okay?

PostPosted: Wed Dec 12, 2018 5:27 pm
by Lion_Jayson
Okay, now i finally understood what you meant. I will try and see how. Thank you very much :D :D

Re: Is my Raspberry Pi 3 B+ okay?

PostPosted: Thu Dec 13, 2018 5:43 am
by ober
Great! How it will works as you expected, do share your progress with us here, videos, pictures are welcome.