Summary of Measuring a water tank level
The author upgraded a water level sensor for an underground rainwater harvesting tank after discovering a slug in the original enclosure. The new design replaces the SRF05 with five HC-SR04 ultrasonic range finders and integrates a 10KΩ thermistor with a matching resistor to monitor temperature alongside water levels. This improved node is part of an Arduino/Xbee wireless network setup intended for future greenhouse projects.
Parts used in the Water Level Sensor Upgrade:
- Perf-board
- HC-SR04 ultrasonic range finder
- IP65 square enclosure
- 10KΩ thermistor
- 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
- Why did the author replace the old sensor?
The original sensor returned only zeros because a slug had entered the enclosure. - What component replaced the SRF05 in the new design?
The SRF05 was swapped for an HC-SR04 ultrasonic range finder. - Are the HC-SR04 sensors compatible with the existing code?
Yes, they work with the same code used for the old sensor and have identical pins. - Where did the author obtain the HC-SR04 sensors?
The author acquired five units from a shopping spree on eBay. - What additional feature was added to measure environmental conditions?
A 10KΩ thermistor and a matching 10KΩ resistor were added to measure temperature. - What project provided the free thermistor samples?
Vishay provided the free 10KΩ thermistor samples for this and future soil humidity projects. - What type of enclosure houses the new sensor?
The sensor is mounted inside a small square IP65 enclosure purchased from Maplin. - What wireless network is being set up for these sensors?
The project involves setting up an Arduino/Xbee wireless sensor network.
