HTU21D Sensor?

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rmtucker
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Joined: 04 Oct 2015, 17:14

HTU21D Sensor?

#1 Post by rmtucker » 19 Dec 2015, 23:12

HTU21D Humidity and Temperature Sensor
Anyone got this sensor working?
I thought it was compatible with the SI7021 but i can not get it too work.

fluppie
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Joined: 09 Oct 2015, 13:23

Re: HTU21D Sensor?

#2 Post by fluppie » 20 Dec 2015, 01:24

Same here, 2 sensors are found by the I2C scanner but it's not working.

rmtucker
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Joined: 04 Oct 2015, 17:14

Re: HTU21D Sensor?

#3 Post by rmtucker » 20 Dec 2015, 01:42

Mine will not even show up in the scanner.
But it works perfectly on the arduino pro mini and mysensors?

rmtucker
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Re: HTU21D Sensor?

#4 Post by rmtucker » 20 Dec 2015, 15:13

Found the problem.
The delays after conversion are not correct in the source code.

Reley
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Joined: 11 Oct 2016, 20:39

Re: HTU21D Sensor?

#5 Post by Reley » 11 Oct 2016, 20:52

I am fighting with a ESP-12E and a HTU21D...

I cannot get it to work. I am using the latest ESPEasy firmware (137).

I connect the + to the 3v3 pin, the - to the ground pin.
then the SDA GPIO-4 and SDL to GPIO-5

In ESP Easy I configure a SI7021 with correct IDX for Domoticz. This IDX is a dummy in Domoticz.
I have set Delay 55 in the config but still I receive:
300649 : SI7021 : Res=0x80 => Error 0x1
300650 : SI7021 : Read Error!

Also the IC2scanner remains empty if I scan....
What am i doing wrong here?

When I connect the sensor to my Uno, I can read the values.. so the sensor does work...

Reley
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Joined: 11 Oct 2016, 20:39

Re: HTU21D Sensor?

#6 Post by Reley » 18 Oct 2016, 10:09

Reley wrote:I am fighting with a ESP-12E and a HTU21D...

I cannot get it to work. I am using the latest ESPEasy firmware (137).

I connect the + to the 3v3 pin, the - to the ground pin.
then the SDA GPIO-4 and SDL to GPIO-5

In ESP Easy I configure a SI7021 with correct IDX for Domoticz. This IDX is a dummy in Domoticz.
I have set Delay 55 in the config but still I receive:
300649 : SI7021 : Res=0x80 => Error 0x1
300650 : SI7021 : Read Error!

Also the IC2scanner remains empty if I scan....
What am i doing wrong here?

When I connect the sensor to my Uno, I can read the values.. so the sensor does work...

nobody with a hint?

costo
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Joined: 21 Nov 2015, 15:03

Re: HTU21D Sensor?

#7 Post by costo » 18 Oct 2016, 14:34

Are you having pull-up resistors on SCL & SDA ?
chech your sensor to see if it has pull-ups, the ESP12 does not have any. You can check with a voltmeter, SDA & SCL should be close to 3.3 volt. If not connect 2 4k7 resistors between Vcc and the I2C bus.

Reley
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Joined: 11 Oct 2016, 20:39

Re: HTU21D Sensor?

#8 Post by Reley » 19 Oct 2016, 09:17

Both SCL and SDA have 3,something volt. (close to 3,3)
This means I do not need resistors right?

It is a NodeMCU 1 board running the latest ESP easy...
I tested with a DHT11 and this works fine with ESP easy.

On an Arduino, this HTU21D works fine as well..

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