Adafruit Industries, Unique & fun DIY electronics and kits. Temperature & Humidity Sensor AM2302 (DHT22) The AM2302 is a wired version of the DHT22, in a large plastic body.
It is a basic, low-cost digital temperature and humidity sensor. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air, and spits out a digital signal on the data pin (no analog input pins needed). Its fairly simple to use, but requires careful timing to grab data. The only real downside of this sensor is you can only get new data from it once every 2 seconds, so when using our library, sensor readings can be up to 2 seconds old. DHT Humidity Sensing on Raspberry Pi or Beaglebone Black with GDocs Logging. Time to start exploring more sensors with the Raspberry Pi and Beaglebone Black!
Today we'll be checking out the DHT11, DHT22 and AM2302 humidity and temperature sensors available from Adafruit In this tutorial we'll be showing how to install a DHT sensor Python library which utilizes C for high-speed GPIO polling to handle bit-banged sensor output. Many low cost sensors have unusual output formats, and in this case, a "Manchester-esque" output that is not SPI, I2C or 1-Wire compatible must be polled continuously by the Pi to decode. Luckily, the C GPIO libraries are fast enough to decode the output. Once we have that working, we add the fun of Python to update a google spreadsheet live with the temperature/humidity data. Pushover: Simple Notifications for Android, iOS, and Desktop. PebblyPi Smart Doorbell. After this tweet… …alot of people asked for some kind of tutorial so here it is First a youtube video of it in action Parts Raspberry Pi Model BPebble Smart Watch + SmartphonePushover App (iOS or Android) plus Pushover AccountA Button to act as the doorbell – I used this Waterproof Metal Pushbutton with Blue LED Ring but you could use any momentary push button.A 10K Pull-up resistor – needed for the button circuit.Multicore cable to connect the button to the RPi – I used telephone cable as it has 4 wires and I needed to both power the LED ring and detect the button pushes.PC Speakers – I just used some that I had lying around.