Water flow warning light

Tool Concept
Functional Prototype


This small gadget uses the water flowing in a pipe or hose to generate electricity to light a small LED to warn that water is being used. We have had a few incidents of forgetting the tap on while it soaks the capillary matting and flooding the garden propagator. The light meant that one can see from a distance that water is flowing. Of course one can change the LED to a small flashing beacon, siren etc. The water generator generates 12v at 3.5w which powers the light. It is a small challenge to change the current to a suitable one for the LED. I managed to convert it using a small 3v voltage regulator and connecting it to a bicycle light. I would have liked it to flash but didn't manage it. I like this gadget because there is no need for sensors or sophisticated switches, it is the use of water which makes the warning light go on. I was also very happy to find these in-line electrical hydro generators. This is my first Farm Hack tool, so feel free to contact me if I am missing any information.
Documentation Wiki: 

Bill of materials

The 3 main componenets are:

1. A small electric hydrogenerator (http://www.amazon.co.uk/Portable-Micro-hydro-Generator-Charger-Efficiency/dp/B00K74GPVM/ref=sr_1_2?ie=UTF8&qid=1449326254&sr=8-2&keywords=micro+hydro+generator) £9

2. A voltage regulator to convert 12v to 3v I bought this one: PowerPOD 1117 3V3 £1

3. Bicycle lights (rear)

4. Hose adaptors to fit the generator inline with the hose

Other tools needed to build this tool


Step-by-step build instructions

First connect the generator to the hose and it is good to measure the voltage output at various stages to make sure that it is working.  The electrical current from the generator goes in to the power pod. There are various voltage regulators which can be limited to one small componenet. I used the power pod as I am not very knowledgable in electronics and it seemed (and proved) convenient. I noticed now that there are better micro generators which will produce smaller voltage (3.6v). that would skip the power pod step.

Again test that you are getting the correct voltage from the genertor and regulator.

It was a bit tricky to get the bicycle lights to work. I basically connected the output to where the batteries are meant to be and short circuit the switch. The one I used had a push button and different flashing options. As I said above I would have liked it to flash but didn't manage.

Supporting materials

ie. SketchUp files, CAD drawings, photos, video, technical drawings. 

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