Hello, I been searching the internet on the ds18b20 temperature sensor. And finding out what I need to know I got a little confused on what resistor should I use between the data line and vcc. Some places say 4.7k and some say 10k. I’m using the pi pico so it will be at 3.3v. I just don’t know which resistor to use. I’m only using 1 DS18B20 sensor.
Can someone please help me out to figure this out?
Joseph
See Fig-1 and check that a pull-resistoe (R1) is needed at the data line (DQ-pin) of DS18B20 sensoe as the driver U2 is an open drain device.
Any reasonable value from 2.2k to 10k works well for UNO. I have idea about pi pico.
@GolamMostafa For uno yes I agree 4.7k I used on 5v in the past. But for pi pico that is on 3.3v I have no clue.
Edit: I just found this https://randomnerdtutorials.com/raspberry-pi-pico-ds18b20-arduino/ right now and looked at it saying to use the 4.7k on the 3.3v.
The I2C spec is 4K7.
One per bus, not per device !
@lastchancename I'm not using i2c. The DS18B20 is a one wire device.
4k7 should still work.
@JCA34F Thank you. That is what I thought as well. I wasn't sure.
When in doubt always consult the data sheet. This is it in pdf format
DS18B20.pdf (333.5 KB)
Are you using a FET like it shows?
Hey @Grumpy_Mike You are right I didn't look at the datasheet. I wasn't even sure looking at it would help me bacause of the different voltage.
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