In Field Battery Operate Latching Valve Water Irrigation Timer Controller With DIY PCB
Introduction: In Field Battery Operate Latching Valve Water Irrigation Timer Controller With DIY PCB
I have a small vegetable farm in Thailand. we still use a lot of worker to do watering. Now I try to make some solution for make a timer for watering plant and use less worker for watering.My requirementis that It must be good on field with out need to lay long cable for electricity. I also don't wan't to controll water from the water center as I already layout pipe on the field . The most important thing is I want to make my own controller which can be customize and expand feature in the future like adding LoRa, Zigbee IOT, Sensors and make that suit my farm.
Before start,I would like to inform you that I'm from Thailand , My English Language may not good but I will try my best, Sorry if there are some mistake in my English in this article.
So . the major key feature of this project is
1.Simple Controll timer for water irrigation by ON-OFF water valve, 4 times a day.
2.Must be battery operate, more safty than use electricity and easy to implement in field.
3.Suitable for running any where in farm that have water pipe.
4.Cost effective.
5.Can be expand feature in the future.
After done several of searching for solution and tools. I come up with Latching vale as the use less power to controll and also use AVR Controller as cheap and easy to find with a lot of resource. I use my old school basic language as easy for me to understand and i use it long before arduino came out so,I go with BascomAVR. I use Autodesk EaglePCB for designed a PCB. Autodesk Fusion360 for make box cover. Now i got every thing ready, Now lets make it step by step.
Parts, Tools and Supply
1. Dc Water irrigation Latching Solenoid Valve. Can be any size depend on size of water pipe. Can be bought from amazon, alliexpress.
2. PCB, PCB Etching Acid, Cutting / Drilling Tools.
3. Electronics component, LCD 16*2 , Atmega328p, Mosfet, Capacitor etc. You can find all component need in Eagle Schematic file.
4. Battery and Battery Holder, Any battery between 7-18 V.
5. 742
Waterproof electronic box.
6. Autodesk Eagle Pcb software for pcb printout, Laser Printer.
7. AVR ISP for programming AVR microcontroller.
Step 1: Knowing Type of Water Solenoi Valve.
There are 3 common type of water solenoid valve. DC solenoid valve, AC solenoid valve and Latching Valve. Most common type that use in many project in watering plant is DC solenoid valve, This type of valve use DC power to energising coil to raises the plunger and enabling flow let water pass through. But this type is not good for batery operate as they need continue power energising the coil.This project then use a Latching Valve. The different to the other is that they need only one pulse or power to energising the coil and the plunger will hold it state. The direction on plunger close or open depend on polarity electric power pulse that apply to the coil.If we apply + - to coil it will pull back plunger in to coil and if we swap it,put - + to the coil it will push plunger out.
This Dc Latching Valve need pulse of power to operate. They need around 6-20 V with about 500ms of pulse time to energising the coil. Once pulse apply they will latch it state there for no need any power to provide ti the coil any more until it need to change it state.That's why it very good for batery or energy saving operation.
Step 2: Circuit Design
For circuit design, I use Autodesk Eagle for design schematic and pcb. Eagle is easy and flexible schematic and pcb designer. I had been using if for very long time. It very suitable for D.I.Y and Hobbyist. This program will allow you draw schematic, place component that need and generate component to pcb board editor. So. There are 2 main editor windows of Eagle , Schematic editor and pcb Board editor. I like this program as you can change or edit or create libraly to suit your project. On Eagle board editor you can arrange component the way you need and manual rout pcb trace as you like. As for me I didn't do very complex pcb or multilayer pcb or any big pcb so it free version /education version of it is more than enough.
Now for this project circuit designed. 33