25-01-2015, 20:20
Just one thought about the the SHT2X sensors family...
They are I2C sensors, so you must be very careful with the length of the SDA, SCL lines, and cable capacitance. In any case, the cable between the sensor and the TX board must be very short, with a very good cable 1 meter máx, which in most cases is not enough.
In my modest opinion, for outside Temp / Hum readings, using a SHT11 is a very balanced choice between price and performance, and it can safely be used with cables up to 6 to 7 meters.
For testing and evaluation purposes, I'm using one SHT21 and one SHT11, side by side on the same RS (each TX unit can have both connected at the same time, and will send data from both. In the software you select wich one will be your main outside temp / hum sersor, and the other is treated as a Extra Sensor) and the readings of both are very similar.
Just as a note, the Davis weather stations are using the SHT11 sensor.
If you want to go with any of the SHT2X sensors, and need a long cable to connect it, there are on eBay some small modules, called I2C extenders, that can handle SDA / SCL lines, up to ten metters.
They are I2C sensors, so you must be very careful with the length of the SDA, SCL lines, and cable capacitance. In any case, the cable between the sensor and the TX board must be very short, with a very good cable 1 meter máx, which in most cases is not enough.
In my modest opinion, for outside Temp / Hum readings, using a SHT11 is a very balanced choice between price and performance, and it can safely be used with cables up to 6 to 7 meters.
For testing and evaluation purposes, I'm using one SHT21 and one SHT11, side by side on the same RS (each TX unit can have both connected at the same time, and will send data from both. In the software you select wich one will be your main outside temp / hum sersor, and the other is treated as a Extra Sensor) and the readings of both are very similar.
Just as a note, the Davis weather stations are using the SHT11 sensor.
If you want to go with any of the SHT2X sensors, and need a long cable to connect it, there are on eBay some small modules, called I2C extenders, that can handle SDA / SCL lines, up to ten metters.