A few years ago, I cobbled together a sensor to monitor the water level of my Christmas tree. Like a bad holiday movie, it’s since sucked me in for a few more hours of tinkering each year. Although its main function is largely unchanged, I’ve added a few more bells and whistles along the way. I upgraded the scrap metal + FoodSaver bag sensing probe to a custom PCB and changed the software platform from Arduino + Adafruit IO to ESP Home, unlocking the full smart home automation power of Home Assistant. The result is a reliable and relatively power-efficient Continue Reading
sensors
Making it rain with Software Defined Radio
For about the same cost as of case of PBR, you can buy a cheap software defined radio called the RTL-SDR. With this simple USB dongle, you can turn your PC into a wideband radio scanner and use it to sniff out RF signals anywhere from 25 MHz to 1700 MHz. In case you’re not familiar, an SDR receiver works a lot like a traditional radio transceiver, except that most, if not all, of the signal processing that would normally happen in hardware, is done with software instead. Essentially, an SDR receiver captures the raw radio signals (using a tuner), Continue Reading
A wireless water level sensor for the Internet of Tannenbaums
(There’s a more recent post with updates to this sensor.) I rigged up a crude little water level sensor to monitor my Christmas tree and send me alerts when it gets thirsty. With the help of two strips of aluminum stuffed in a FoodSaver bag, an Adafruit HUZZAH32 – ESP32 Feather Board, and a little Arduino code, our humble tree has become part of the IoT revolution! Physics lab flashback The sensing probe that goes in the water is basically just a parallel plate capacitor straight out of undergrad physics. The water flows between the plates and works as a Continue Reading