This flower pot has a built-in sensor that detects when the soil is dry and lets you know. The circuit uses an ATtiny85 as the brain and copper tape as the sensor. It is powered by 2 AAA batteries. All of the electronic parts can be purchased at http://sfe.io/w90611.
- 4.7 uf Capacitor
- 47k Resistor
- 330 Resistor
- Blue LED
- 2 AAA batteries and case
- Copper Tape
- Flower Pot
- ATtiny Programer
- Soldering Iron
Story About Why I Built This
A long time ago (last week) I decided that I wanted a plant. After shopping around, I found this pretty awesome bonsai plant/mini-tree. However, I soon discovered that I was horrible at remembering to water it (you can see in some of the photos that the leaves have started to turn yellow). So I decided to revisit an old and never finished project I was working on regarding soil moisture. (Most of it was following instructions from http://gardenbot.org). However, I thought to myself "an Arduino is huge for a little mini-tree. I should use an ATtiny." And after some surfing on the web, I got inspired from http://highlowtech.org and thought that copper tape would be cool for the sensor and maybe even the circuit. So I put my thinking cap on and got to work.
Step 1: Program the ATtiny
Go ahead and start by programing the ATtiny. You can follow my other instructable to use the Arduino IDE to program the ATtiny85 chip. If you don't have the amazing Tiny AVR Programmer from Sparkfun.com, it is possible to program an ATtiny with an Arduino (my other instructable has a link on how). Once you have the sketch uploaded to the ATtiny go ahead to the next step.
Step 2: Build the Circuit
Now you want to use the copper tape to build the circuit. I found it helpful to tape down an ATtiny so I could see where the pins are.
The distance between the two strips of copper tape used for the sensor is supposedly critical, but I found in testing that it did not make a huge difference. Mine are about 2 cm or 3/4 of an inch apart. They extend a bit more than halfway down the inside of the flower pot. This circuit is prone to electrolysis. You can find out more about this circuit at http://gardenbot.org/howTo/soilMoisture/.
Step 3: Add the Components
Now use needle nose pliers to bend the component legs. After you have the components in the right shape, go ahead and tape them down to the flower pot (Keep the circle parts free from tape, as you will be adding solder there). When soldering them to the copper tape, I found it best to add solder to the component legs then making the connection to the copper tape. Be careful I've heard that melted plastic fumes can be toxic. Don't forget to add the battery pack to the back.
Step 4: Add the Plant
Transplant the plant. If you know what my plant is, please comment below, I want to learn more about it. I hope that you found this instructable useful or cool. If you did, please vote for me in the contest.
I think that it would be cool to use a 3-d printer to make a flower pot that has a hole for the batteries so that it was weighted evenly and didn't have an awkward back.