05-06-2016, 03:39
Hi Graeme
To use the HTU21 or an SHT21, the I2C bus extender chip is not absolutely necessary, but you have to connect your sensor to the connector marked as I2C, not the one marked with SHT2X/EI2C.
With a 2 par twisted cable up to 3 meters you shouldn't have any problem. (Ex: One par - VCC and SCL, other par - GND and SDA)
I don't know if the HTU21 share the same sensitive elements that the SHT21, but one, can't be read using the reference of other. So if you are using a HTU21, in the software, choice an HTU21, exactly as you did.
This issue is happening certainly because the WD unit, is receiving a wrong temperature value. Don't do anything on it until the wrong temperature readings are solved.
If you are using a Davis Wind Vane, don't care about adjusting the R6 pot, it is only used for the the Fine Offset vanes. The JP2 jumper should also be left open.
Regarding the wind speed readings, recheck the connections again. Remember that the pin out of the original Davis RJ12 connector, is not compatible with the WeatherDuino Pro2 RJ12 connector. Please do a search on the forum, there is a topic about this matter with a diagram of the required connections.
Also check user configurable options on the software, default values are set for Fine Offset instruments. For Davis wind instruments they should be:
Thank you, and please let us know how things are going.
Edited: Seems you have posted the last message, almost at the same than I wrote this one
(04-06-2016, 12:42)spudstrawb Wrote: This might be the problem... I found this quote from Werk_AG in another thread:
"The question is, the SHT2x series communicates using the I2C protocol, which implies that you also have to install the I2C bus extender Philips chip on the TX unit, which is not required for the SHT1X series."
I haven't installed an I2C bus extender. I'll either get hold of one or else get an SHT1X sensor.
To use the HTU21 or an SHT21, the I2C bus extender chip is not absolutely necessary, but you have to connect your sensor to the connector marked as I2C, not the one marked with SHT2X/EI2C.
With a 2 par twisted cable up to 3 meters you shouldn't have any problem. (Ex: One par - VCC and SCL, other par - GND and SDA)
I don't know if the HTU21 share the same sensitive elements that the SHT21, but one, can't be read using the reference of other. So if you are using a HTU21, in the software, choice an HTU21, exactly as you did.
Quote:I have another problem now. My WD unit is locking up. Once it gets the values from the RX unit, either the screen goes white or it locks up (the 2 dots stop blinking).
This issue is happening certainly because the WD unit, is receiving a wrong temperature value. Don't do anything on it until the wrong temperature readings are solved.
Quote:I also hooked up the Davis anemometer. Wind direction seems to come through okay, but nothing comes up for wind speed.
Also, I understand that I have to adjust R6 to 10k. Where do I measure across for this reading?
If you are using a Davis Wind Vane, don't care about adjusting the R6 pot, it is only used for the the Fine Offset vanes. The JP2 jumper should also be left open.
Regarding the wind speed readings, recheck the connections again. Remember that the pin out of the original Davis RJ12 connector, is not compatible with the WeatherDuino Pro2 RJ12 connector. Please do a search on the forum, there is a topic about this matter with a diagram of the required connections.
Also check user configurable options on the software, default values are set for Fine Offset instruments. For Davis wind instruments they should be:
Code:
#define WSpeedSensor_Type 30
#define WDirSensor_Type 30Thank you, and please let us know how things are going.
Edited: Seems you have posted the last message, almost at the same than I wrote this one