Instructables
Picture of VISUALIZE humidity with the SHT11 sensor
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This is a super sensitive, precise sensor for just 35 dollars (for example here at adafruit)
It tells you the temperature too.

I adapted this from my tutorial on my blog

I was trying to figure out how to use the Sensirion Parallax humitidy sensor to output humidity data using Arduino. Finally, I found a library If you want to measure humidity data using the SHT11. 


 
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Step 1: WHAT YOU NEED

Picture of WHAT YOU NEED
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1 Arduino
1 SHT11 Humidity Sensor (There are two data sheets, there is the sensirion one, and the parallax one)
A few wires
a breadboard
1 USB

Step 2: Wire the sensor

Picture of Wire the sensor
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At first I found this hard to tell what needed to hook up to Arduino. 

Using the datasheet from Parallax was eventually the most helpful for me. (see the first image here or the datasheet, under the "connections" section)

Because there are built in resistors, I was simply able to hook it up like this: 

SHT-11 PIN 3 (SCK)  ---> ARDUINO PIN 11 (SCK)
SHT-11 PIN 4(VSS) ----> ARDUINO's GROUND 
SHT-11 PIN 1 (DATA) ----> ARDUINO PIN 9 (data)
SHT-11 PIN 8 (VDD) ----> ARDUINO +5V



Step 3: Program Arduino

Picture of Program Arduino
Download the library from https://github.com/practicalarduino/SHT1x
Move Sht1x folder into Documents/Arduino/Libraries

Restart Arduino

Under File-->Examples, you should see SHT1x

Open it (called ReadSHT1xValues.pde)

Upload the sketch,

Step 4: See the values

Picture of See the values
Temperature: 25.4199981689C / 77.8459930419F. Humidity: 23.45%
Temperature: 25.4399948120C / 77.8639984130F. Humidity: 23.45%
Temperature: 25.4799957275C / 77.7919921875F. Humidity: 25.12%
Temperature: 25.4599990844C / 77.8999938964F. Humidity: 27.65%
Temperature: 25.3600006103C / 77.7739944458F. Humidity: 27.87%
Temperature: 25.5199966430C / 77.9719924926F. Humidity: 26.86%

... 
and so on. 

This sensor is supposedly very accurate and also, very inexpensive. 

(More to come... HOW TO LOG THIS DATA and VISUALIZE IT in a graph...)

did you using the DHT11 too?.. does it more acurate than SHT11 or not?

taqiya7 months ago

i cant download the sketch. please fix it

alexjaw698 months ago

Arduino data pin 9 should be changed to pin 10 if the SHT1x code is used as is.

Thank's for a nice instructable. I had an old SHT11 sensor and was pleased to see that I could interface it so easily with Arduino (YUN).

FINALLY AN INEXPENSIVE ACCURATE HUMIDITY SENSOR 'IBLE !!!!!!!

Many many thanks gabriellalevine !!!

just out of curiosity, how much did the sensor cost you and is there a way to get the raw components together to solder myself so that this would be EVEN cheaper ???

(Note: im always making homemade PCB's and prefer to buy lose components to make 5 units for the price of 1 !!! lol)
http://www.adafruit.com/products/246 here is it 35 dollars. You can check the components, I'd look at the sensirion or parallax data sheets I linked to in Step 1
OUCH @ $35 USD !!!!!!!!!!!!!!!!!!!!!!!

Wow, i think we have two completely different thoughts of what inexpensive mean, lol x 2! !!!

You've made an AWESOME instructable so MAJOR credit to you there but inexpensive to my eyes is something like This!!!
 (which is what will be replacing the SHT11 humidity sensor in the future!)
Thats ONLY £0.99p !!!!!  ( $1.56 USD !!!!!!!!!! )

and as the schematic shows that this humidity sensor's circuitry only uses TWO resistors and a PCB im really wondering how-on-earth thats all worth such an 'Extortionate' PRICE especially when Resistors are worth around 0.01 or even 0.001 in ANY currency, lol x 2 !!!

You can find real easy Homemade PCB making techniques here on instructables and i guarantee you - you'll get more satisfaction out of your projects if you make them all almost from scratch, save yourself 100's of Dollars that you can better spend on MORE components!!! lol x 2 !!!!

Somehow i dont think two Resistors, a TINY PCB and a Humidity sensor is worth $35 USD - Not in a million years !!! (Especially for the poorest of the poor people out there, like me, lol !!!)

Anyhoo thanks again for the TOP 'ible as ive been looking for the circuitry to make a PCB for my humidity sensor for weeks, major thanks for the point in the right direction & im looking forward to the addon of how to visualise this data in a graph !!!

5-STARTS ADDED !!!
Hm. Ive tested a number of temperature and humidity sensors. I've also used expensive omega tools http://www.omega.com/pptst/OM-DVTH.html for testing moisture, and this sensirion humidity sensor seemed to be far more accurate compared to the other ones. So, compared with the price in the hundreds USD, this is cheap for its high functionality. But I'm sorry I misled you
Nope! No apology necessary !

i appreciate the sentiment though!

But if it wasnt for your handy 'ible i would still be stuck in trying to create a PCB for my selection of humidity sensors i have acquired over the last few months!!

i have the 1st two humidity sensors you posted links to but bought them from my fav.electronics superstore - EBAY - lol ! and at a Quarter of the price that adafruit are selling them for and i even had free shipping!

always check out ebay as ive found that 8 times out of 10 you'll find exactly what you need as long as you dont mind the 2/3 weeks from buying from China/Honk Kong as they charge such low prices for their electronics that i buy a good 90% of my electronics from them!

The 'Big-Name' companies tend to inflate the prices of these things considerably but with the SHT11 sensor i did see in the datasheet that it is indeed FAST with detecting changes in Temp/Humidity as opposed to the DHT11/DHT22 varients. I guess that naturally the more you pay, the better tech you get a !!!!!!

So infact its a Major-Thanks for the nicely laid out 'ible, nice and simple for my beginner-electonics-brain to handle !

no bad karma at all !!

;-)
Also, here is another one I tried, that are less expensive, but I think less accurate:
http://www.adafruit.com/products/386
http://www.adafruit.com/products/385
http://www.adafruit.com/products/393