Wire two Dallas ds18b20

DMendoza
Posts: 4
Joined: Wed Jan 11, 2017 10:37 am

Wire two Dallas ds18b20

Postby DMendoza » Wed Jan 11, 2017 10:44 am

Hi, I would like to know if the libraries of the Dallas sensors are compatible to be able to connect in a wire two dallas ds18b20

dennis650
Posts: 5
Joined: Mon Dec 19, 2016 11:52 am

Re: Wire two Dallas ds18b20

Postby dennis650 » Wed Jan 11, 2017 1:25 pm

Hi,

yes. OneWire is a bus. I have 4 DS18B20 in row, one DS2438 and a DS2406P on just one ESP32 GPIO. The OneWire Devices have different adresses.

Greetings
Dennis

DMendoza
Posts: 4
Joined: Wed Jan 11, 2017 10:37 am

Re: Wire two Dallas ds18b20

Postby DMendoza » Wed Jan 11, 2017 3:36 pm

Thank you

kusumy
Posts: 1
Joined: Tue Oct 22, 2019 2:36 pm

Re: Wire two Dallas ds18b20

Postby kusumy » Mon Oct 28, 2019 12:29 am

hi @dennis650, can you share an esp32 library to access DS2438 ?
Thank you

JacktheRipper
Posts: 14
Joined: Fri Nov 08, 2019 2:04 am

Re: Wire two Dallas ds18b20

Postby JacktheRipper » Fri Nov 08, 2019 2:24 am

I have been using an Adafruit HAZZAH ESP32 connected to three ds18b20 sensors. They are connected in parallel, and I use the standard DallasTemperature.h Arduino library. When connected as a full three-wire sensors (separate GND, 3.2V and signal wires) they work perfectly. When connected using the two-wire approach (sensor GND and VXX shorted together at the sensor connected to GND at the ESP32, and a signal wire) they don't work. Either they are very inaccurate, or they return nothing. This two-wire configuration has worked fine for me at 5.5v with both a UNO and a Nano. Must include the 4.7k pullup resistor to the signal pin.

Edje11
Posts: 18
Joined: Thu May 17, 2018 10:33 am
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Re: Wire two Dallas ds18b20

Postby Edje11 » Fri Nov 08, 2019 3:36 pm

You have to en bale the parasit power mode for the ds18b20 in Arduino.

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