Use this forum to chat about hardware specific topics for the ESP8266 (peripherals, memory, clocks, JTAG, programming)

User avatar
By btidey
#72973 The maxim app note https://www.maximintegrated.com/en/app- ... mvp/id/148 provides some useful information.

Reports of successfully achieving distances of 50m seem to benefit from lower pull ups (e.g. 2.2K) and wiring the data/gnd as a pair, and the supply/gnd as another pair. Some also say some sensors benefit from being run at 5V but with the one wire pull up to 3.3V.

Having said that, my personal strategy is to avoid long cable runs which are a pain in the neck for all sorts of reasons. The big benefit of the ESP modules is to avoid this by putting them next to the sensor and letting wifi replace the cable. They are sufficiently small and cheap to sprinkle them around as required. Obviously the wifi range can become a factor but there are chaining methods that can be employed if that becomes a problem.
User avatar
By btidey
#73003 That's a good point. I normally use ds18b20 as they are fast and accurate.

Checking further on the dht22 indicates it is a different 1 wire interface and not addressable so daisy chaining multiple units on the same wire is not possible, unlike the ds18b20.