Summary of Measuring a water tank level
The article describes the development of a new water level sensor for an underground rainwater harvesting tank. Initially, the Arduino/Xbee wireless sensor network failed due to a slug intrusion, prompting the creation of an improved sensor. The update involves replacing the SRF05 ultrasonic sensor with a cheaper HC-SR04 alternative housed in an IP65 enclosure. Additionally, a 10KΩ thermistor and resistor were added to the perf-board for future soil humidity and temperature sensing projects.
Parts used in the Water Level Sensor Project:
- Arduino
- Xbee wireless module
- HC-SR04 ultrasonic range finder
- Perf-board
- IP65 enclosure from Maplin
- 10KΩ thermistor (Vishay sample)
- 10KΩ resistor
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 
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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
For more detail: Measuring a water tank level
