The plan.

Solar Mini Greenhouse

Objective: Create a simple solar powered mini greenhouse with the following features.

   

For the plants

• Records daily light levels. (every 2 min?)
• Records daily temps. (every 15 min)
• Records Moisture levels .(every 5 mins Starting at sunrise)
• Water plants during light hours.(cutoff at midday)

   

For the PV panel

• Record temps throughout the day.
• Record light level throughout the day.
• Record PV voltage throughout the day.
• Record current consumption throughout the day.

For Battery backup

• Record Battery charge time.
• Record battery charge events.
• Record Battery voltage throughout the day.

Required:

• Solar panel - purchased a 10W 12V panel
• Microcontroller(MSP430, Arduino)
• Light level indicator.(Look at TAOS)
• Moisture level indicator.(cheapy chinese things)
• Data transportation method (transceiver like an RFM12B or NRF24L01+)
• Watering system.

Thoughts, ideas, and notes.

• Inital idea was to use a cheap water pump that runs on 5-12 v
• Another option is using siphoning
• Other option is to use a gravity feed setup, though the water will need to be above the greenhouse. The thought on this is that a cinder block can hold the water bottle for the gravity feed system
• Another option using the gravity feed is to include a way to pressurize the bottle as well. One thought is to have a water bottle painted black that has a tube connected to the main bottle. During the day, the bottle painted black will increase in pressure thus presurizing the system. A 1 way in valve would allow air to come in, but not go out, so as the water is drained, the system equalizes. Opening the bottle to refill does depressurize the system however. This may or may not work as thought.

Plant nodes.

• A plant node can be a simple device that just measures the plant moisture level and internal temp of the uC. The node would be hooked up to a main base station via a simple servo wire(3 lead).
• Communication via serial transmit only from Node(S) which would wait for a Master(M) send requestion(high -> low), Master would set itself to receive mode and wait for data. Node would be in standby until data was required. Consider options for multiple nodes sharing the same serial port.
• Node uses ADC pin for moisture sensor.
• Node uses ADC for temp aquisition.
• Node uses 1 pin for serial communication
• Other pins free to be used for other things.
• Moisture sensor should be controlled via transistor.

Initial prototype build.

The initial prototype has been built with the following:

• Ikea mini greenhouse
• Arduino pro mini 3.3v@8Mhz
• moisture sensor
• Solar powered
• battery backup