The system designed here is for watering plants by just pushing a button. The design is pretty simple and the Overall cost of this is approximately $15-$20 (Rs. 700). My plants need about 1.5 - 2 minutes of water once a day (twice during the summer), hence I have programmed the microcontroller accordingly. So All that needs to be done is push the button and all the plants are watered automatically. I have set this up at my home and using it for a few months now.

I have not made this completely autonomous (water the plants at a preset time during the day) since there is no guarantee of uninterrupted power supply here by the power companies and I am not using batteries. We don't want a system reset because of power outage.

There are two modules to be prepared:
1) The Water pipes with a Solenoid to release/hold water supply to the plants

2) Controller circuit to regulate the water supply

Step 1: Materials Used

For setting up the Water pipe network:

Water pipes

Solenoid (This costs the most - Rs500/$10, high quality)

pipe connectors

metal clamps

Screw driver

My Niece's old sketchpens

Tap connector

For the controller circuit:

Microcontroller 2051

Crystal - 11 MHZ (Y1)

Push button switch (S1)

Capacitors - 33pf (C1, C2), 10uf(C3)

Resistors - 8.2K (R1) 800 ohm (R2)

Diode - IN4148 (D1, D3)

Transistor- TIP122 (Q1)

LED (D2)

Prototye board

connecting wires

Soldering kit

2 Adaptors as power supplies. B1 (5v, 1Amp) and B2 (12v, 1Amp)

Step 2: Setting Up the Watering System

Calculate the length of pipes you would be needing from the water source to cover all your plants/pots. The Solenoid needs to sit between the water source and the first plant/pot that needs to be watered. Also, the solenoid needs to be connected to the controller circuit, so make sure the wires can reach it.

Connect the pipe to the water source. This can be done using the tap connector and a clamp. Make sure not a single drop leaks, we don't want to be wasting water. Its one of the main purposes of this setup. Connect the other end to the solenoid, might need to use a connector, PVC glue and tape. The Solenoid has an arrow pointing the direction of water flow. Make sure it connected the right way. Once this is secured, release the water from the tap to make sure there are no leaks. Next, connect the Pipe to the other end of the solenoid and place the pipe in such a way that it runs near or over the pots. Using a screwdriver with a pointy head, make holes at required locations. Make sure the hole isn't too big.

I have used some old sketch-pens as emitters as shown in the pictures. Removed the nip of the pens and sliced out a part of the other end. This can now be easily pushed into the opening made using the screwdriver. It could be different for you setup, so plan accordingly.

The end of the water pipe has been placed in such a way that it rises above the level of the pots. So no necessity of closing the end of the pipe,

Step 3: Control Circuit

A simple circuit for controlling the flow of water is shown.

Adaptors are used for power up this system. One is needed to supply the high current to the solenoid (12v, 1amp), other one for the Microcontroller (5v, 1amp).

Programming the MC.
This is the program I used for the microcontroller in hex.

:03000000020006F5
:0C000600787FE4F6D8FD75810D02004DF6 :04015C000208000095 :01016100227B :0300030002014FA8 :0D014F00C0E00509E50970020508D0E032A6 :10010300E4F50AF50BAE0AAF0BE4FCFD7B607AEA7B :10011300F9F8D3120139401DE4F50CF50D050DE591 :100123000D7002050C6405450C70F2050BE50B70B0 :06013300D4050A80D02271 :10009200D288D2A8D2AF7590F0D3E5099400E508D2 :1000A2006480948040F3120103C2A875900CD3E5DA :1000B200099400E50864809480403FE4F50AF50B5A :1000C200AE0AAF0BE4FCFD7B607AEAF9F8D31201C9 :1000D20039401DE4F50CF50D050DE50D7002050C1A :1000E200640F450C70F2050BE50B70D4050A80D045 :1000F200E509150970B8150880B4D2A875908080FA :010102009864 :10001200020092E493A3F8E493A34003F68001F272 :1000220008DFF48029E493A3F85407240CC8C333EF :10003200C4540F4420C8834004F456800146F6DFBE :10004200E4800B010204081020408090015CE47EF1 :10005200019360BCA3FF543F30E509541FFEE493B3 :10006200A360010ECF54C025E060A840B8E493A37A :10007200FAE493A3F8E493A3C8C582C8CAC583CAA5 :10008200F0A3C8C582C8CAC583CADFE9DEE780BE5D :01016000009E :10013900EB9FF5F0EA9E42F0E99D42F0EC6480C83D :0601490064809845F022DD :00000001FF

Once the button is pushed, there is a five second delay before the interrupt is diabled and water begins to flow. So if the button is pushed twice within a 5 second interval, the water is released for around 2 mintues. (and so on..) The 5 second interval starts once the button is pushed for the first time. After the 5sec interval the button is disabled and water is released. The circuit is ready for interrupts once the water release is over.