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Wire two Dallas ds18b20
Posted: Wed Jan 11, 2017 10:44 am
by DMendoza
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
Re: Wire two Dallas ds18b20
Posted: Wed Jan 11, 2017 1:25 pm
by dennis650
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
Re: Wire two Dallas ds18b20
Posted: Wed Jan 11, 2017 3:36 pm
by DMendoza
Thank you
Re: Wire two Dallas ds18b20
Posted: Mon Oct 28, 2019 12:29 am
by kusumy
hi @dennis650, can you share an esp32 library to access DS2438 ?
Thank you
Re: Wire two Dallas ds18b20
Posted: Fri Nov 08, 2019 2:24 am
by JacktheRipper
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.
Re: Wire two Dallas ds18b20
Posted: Fri Nov 08, 2019 3:36 pm
by Edje11
You have to en bale the parasit power mode for the ds18b20 in Arduino.