DHT11? Code/Schematics?

[wdmagic]

Im looking at a DHT11 Digital Humidity and Temprature Sensor.

Need datasheet, schematics, code for it.

All I really need is a humidity sensor but I havent had good luck finding a solo digital sensor. If anyone knows of one let me know.

[Aussie Barry]

Hi Chris,

I hope this helps.
http://robocraft.ru/files/datasheet/DHT11.pdf

Cheers
Barry
VK2XBP

[wdmagic]

thanks for the quick response, now I'm thinking thats going to be a bit hard to get working at my level. anyone know a simple humidy sensor thats easy to interface with?

[gadelhas]

thanks for the quick response, now I'm thinking thats going to be a bit hard to get working at my level. anyone know a simple humidy sensor thats easy to interface with?

Hi wdmagic;

Search for SHT11. It's a humidity and temperatura sensor from Sensirion ( http://www.sensirion.com/en/products/humidity-temperature/humidity-sensor-sht11/ ). They are very good sensors, and i think that you will find code here on the fórum. If you don't find it, tell me that i will send you one that i have been using, but i don't have it here with me.

[peterdeco1]

Looks very straightforward.
http://www.emartee.com/product/41488/

[wdmagic]

yea that one is a analog, and it should work, but its got a +/- of 5%RH which I was hoping to get a bit more acurate than that. I found a Humidity sensor that requires a 555 timer circuit and it outputs frequency based on RH value and its got a +/- of 1%, its a HS1101, its also only $4 on ebay. I have found out though that the sensor itself is only a varible capacitor based on humidity levels, this one ranges from 163pf @ 0% humidity to 201pf @100%. and I was wondering if its possible to use the RCTIME with a fixed resistance to read the pf values, although that is very small, also I would like to have a resolution of 100. now I can build the 555 circuit and use PULSEIN but it would be cool to be able to read the humidity with only a sensor and a resistor.

here is the datasheet (http://pdf.datasheetcatalog.com/datasheet/humirel/HS1100.pdf) on the sensor, it also has the info on the 555 in it. it says with the 555 circuit it can output 5k-100khz pulse but only uses a small range in those limits, so if I do use the 555 I will set it to run from say 20k-30k based on RH values if PULSEIN can handle that.

[Charlie]

Just a caution... I'm not sure what your application is that requires better than 5% accuracy given most home humidity controls or weather stations are more like 10%, but be sure you take the whole circuit and it's environment into account in your calculations - the nominal error of a 555 with standard components, the temperature impact on all the devices, and so on. You may quickly find that your 1% device, in the real world, actually reports worse than the 5% device. YMMV.