I have another project, the plant moisture sensor, that can detect the water level in soil. This is a follow-up to that, so you can use what data the sensor provides to do something useful (like water a plant). This is made completely out of household supplies, with the exception of a servo motor, so anyone can easily make it.
Step 1: Tools and Materials
- Glue gun
- Drill or something to make a hole
- Craft sticks
- Drinking straw
- Small servo motor
- Plastic cup
Step 2: Insert Straw
- Punch a hole slightly larger than the straw close to the edge of the cup (you can use anything, but I chose a drill because it made a clean hole).
- Slide the straw through the hole about half an inch.
- Glue around the straw and cut it to about 3 inches.
- Put a clothespin around the straw and glue it to the cup.
Step 3: Attach Servo
- Glue a craft stick to the clothespin along the side of the cup.
- Add another craft stick at an angle to the first.
- Glue the servo motor so it is facing the straw.
Step 4: Add the "Valve"
- Glue a piece of a craft stick to the end of a clothespin (you can just cut it with scissors).
- Glue around the clothespin so it can't wiggle around.
- Slide it over the straw so it is even with the top part of the servo motor.
- Glue it to the servo (you will need to be careful to make sure the end piece won't get caught on anything when the servo turns).
Step 5: Add Legs
- Glue a craft stick every few inches around the edge of the cup to provide a base so the cup can rest above whatever it has to water.
Now you can use this with an Arduino (or other board):
- When the servo is down (180 degrees), water will flow from the cup through the straw.
- When the servo is at a 90 degree angle, the water will be trapped inside.