I2C Temperature and Humidity Sensor (SHT31)

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MotooTanaka
Level 9
Level 9
Distributor - Marubun (Japan)
First comment on blog Beta tester First comment on KBA

One day, the ad of this sensor appeared on my web browser again and again.

When I read the description it seemed to be interesting, so I ordered my Digi-Key account a couple of this sensors.

The price of the sensor was about $9.00, so $18.00 for two, but the shipment costed me more than that.

A few weeks later, at Akizuki in Akihabara, I found a module of this sensor being sold about $9.00.  orz

Anyway, I wrote a simple test program for this, the hardest part was calculating the CRC value.

IMG_2797.JPG

I used MSS (Marubun Sensor Shield) to provide I2C signal pull-ups.

I could have used a couple 10K resistors, but this was easier.

(Refer to the schematic below)

SHT31.JPG

Since the sensor is connected via I2C, SDA and SCL must be pulled up.

And I connected the PIN 4 (ADR) of SHT31 to GND, so the slave address is 0x44.

TeraTerm_log.JPG

At the first loop, since the register values were not assigned the result were 0x0000 and 0xFFFF.

But from the second loop, the sensor reports reasonable values.

moto

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