Commercial traveling irrigators are expensive bits of kit which often require high water pressure and supply. There are cheap domestic units which work well under domestic water supply. I got a Nelson Rain train. They are built for established and level lawns. They work on a simple and clever principle of following the water hose which feeds them (The hose is fully extended when they are set) and pulling it back. The rotation of the sprinkler arms move the gears and wheels (and make a wonderful pattern). I thought it would make a good traveling irrigator for my freshly planted or seeded beds in my market garden. However, If this domestic sprinkler is watering bare soil it often gets stuck in the wet area it created. Also, as my fields are sloping the poor little thing struggled both up and down hill. The principle of my tool was to attach the sprinkler to a winch and pull the irrigator a long.
The winch is an atv winch with a 2000lbs pulling power (that is the smallest one I found on ebay). It is operated by a 12v battery and controlled by a timer which turns it on and off in order to pull the irrigator slowly a long the beds. The winch is mounted on a metal frame. The frame has pointed legs which are set in the ground. The whole thing is anchored by the weight of the battery which sits on top and an additional angle iron set in the ground behind it and secured with rope. The steel cable which the winch came with was replaced by a strong and thin 100m fishing wire (pulling capacity 300lbs).
The timer is a 12v analogue timer (I used this). A 80amp relay needs to be added between the timer and the winch as the current is too high for the timer. Electrical scheme is attached. It is important to keep in mind that the winch draws considerable current so wires need to be thick and I added a fuse before the timer.
Currently, I am working with 2 minutes off and 7sec on. the irrigator can water an area of 8m wide and about 80m long in 6hours.
This is a working prototype. Still to be worked out:
An override button to wind the string in without changing the timer.
Stop mechanism- for that I am considering a flow switch so that the winch stops when the water stops. The Nelson rain train has a built in valve which stops the waterflow at a certain point. Once the it reaches that point the water stops and so does the electrical current to the winch.
12/07/2020- I managed to add this function to the project. Using a 1" flow sensor (from eBay) a relay and an Arduino. The sensor sends pulses which are picked up by the Arduino controller. The 5v relay is connected on the coil side to the Arduino and in the switch side, in series to the timer. The relay is set to 'Normally closed' position (thought it can be set the other way) which means that when the Nelson rain train reaches the ramp and the water flow stops, the Arduino will activate the relay and open the circuit which will stop the timer. I'll put in the code in a file below. (Water_flow_sensor3_nomonitor.txt)
Quick release of the raintrain from pulling string.
A box to put all the controls in a neat way.
Happy for any comments and suggestions for improvements.
