The Smart Humidor


If you’re a cigar aficionado, you know storing cigars at the proper temperature and humidity is something you just need to do. Centuries of design have gone into the simple humidor, and now, I guess, it’s time to put some electronics alongside your cigars.

The design of [dzzie]’s smart humidor consists of an Arduino, WiFi shield, LCD + button shield, and most importantly, a DHT22 temperature and humidity sensor. In a bit of thoughtfulness, only the DHT22 is mounted inside the humidor; everything else is in an enclosure mounted outside the humidor, including a few buttons for clearing alerts and logging when water is added.

The smart humidor reads the DHT22 sensor every 20 minutes and uploads the data to a web server where useful graphs are rendered. The control box will send out an alert email to [dzzie] if the temperature or humidity is out of the desired range.

16 thoughts on “The Smart Humidor

  1. I have a problem with those temp + humidity sensors. A friend bought a few(5ish maybe) and tested in the same conditions there was almost 20% RH spread and over 2 degrees C temperature spread. They were purchased from ebay…

    1. A friend and I did something similar for a mushroom terrarium. We used an Arduino UNO, DHT22 (the DHT11 only reads up to 80% humidity), shift registers, x2 7seg LEDs, x2 relays, a Sparkfun heat pad and a humidifier.

      We cracked open the humidifier and ran one of the 5v lines to a relay, also hooked up the heating pad to a relay and a separate 9v power source and voila – an automated terrarium. The UNO would constantly read the humidity and temp, turn on the heating pad if temperature dropped to a certain level, and turn on the humidifier if the humidity dropped. Obviously the 7segs are to display the temp/humidity.

      It turned out great, and the DHT22 gives us perfect readings (we’ve compared it to an analog hygrometer and thermometer.)

      We bought the DHT22 off Amazon – Mike’s link to Sparkfun is also worth the read since re-hydration is an issue.

  2. So would the next step up be something like the Sensirion SHT15 or Honeywell HIH6130 with their claims of better than +/- 4% RH accuracy?

    The Honeywell is interesting in that it is a $30 part with I2C and built-in alarm signal line features,

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