1. Introduction:
I made a water level sensor a little while a go to measure the water level in my underground rainwater harvesting tank. Thanks to the Jubilee I found time to finally setup the first part of my Arduino/Xbee wireless sensor network and the first sensor node was also meant to read from this water level sensor. I was somewhat surprised when it only returned 0s so I went and had a closer look. How the slug got into the enclosure is still a mystery to me… but looking at the bright side (after the uncontrolled swearing) I now had a reason to build a much better water level sensor 🙂
2. Add a few new bits…:
I’ve based the new sensor on the little perf-board from my sensor in Arduino project 6 but swapped the SRF05 for a HC-SR04 and mounted the result into a little square IP65 enclosure from Maplin.
Last shopping spree on ebay has resulted in me now being in possession of five HC-SR04 ultrasonic range finders which are very much a cheap “alternative to the SRF04. These work with the same code I used for the old sensor and have the same pins.
Since Vishay provided me with a whole bunch of free 10KΩ thermistor samples (I’m planning to use these for my soil humidity/temperature sensors for the upcoming Arduino controlled greenhouse v2 project) I added one of those to the perf-board together with the matching 10KΩ resistor.
3. Stir…:
– Remove the angled pin headers from the HC-SR04 and solder wires directly to the sensors control board
– drill two eyes into the top of the enclosure for the sensor eyes
– drill two more tiny wholes into the bottom of the enclosure for the LEDs
– mount sensor and perf-board into enclosure
– pass wire into the enclosure and connect everything up
– seal the holes with hot glue
– mount new sensor into collar of water tank
[3dpix id=4fca72bf378501a75e000003 width=500 height=170 mode=parallel]
4. Serve:
After connecting it to the Arduino Uno everything woked well with the same code as before. So I added a bit more code to read out the additional thermistor which also went well.
The result is now my first wireless sensor node which collects temperature, light level and water level which are then uploaded in 3min intervals by the XBee-to-Ethernet concentrator into my MySQL database 🙂