Solar Powered Wireless Network

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2017-02-11

A wireless sensor node, powered by a rechargeable battery and a solar cell. For outdoor agricultural use.

• Create a few nodes: uC + RTC + nRF24L01 + 3V power supply (perhaps just a coin cell)
• Program 2 of them to run 2 way communications
• Program 2 of them to communicate only in the first seconds of a minute
• Consider RTC syncronisation
• Design a mesh/tree protocol for a network, get this running smoothly

The only interesting item here (and the one that implies the use of an RTC) is the mesh networking. I'm considering the idea of the devices only being on for the first few milliseconds of each second, or 10 seconds, or minute etc. It depends largely on the accuracy of RTC sync systems and the amount of time needed to establish communications in a network in order to any perform any required housekeeping. List of considerations:

• Duty cycles
• Time sync
• Routing protocols (the really tricky bit)
• Node health
• Sending large (1 - 10 MB) files

It may be easiest just to adapt something like RF24Mesh

Now the hard bit is over. All that's left is the solar integration.

• Calculate energy consumption
• Check daily insolation (should be around 1.0 kWh/m^2 worst case)
• Size battery and solar panel
• Choose a charger and DC/DC booster, and any other circuitry required (diodes, cuttoff)

2017-09-29

The SX1278 seems like an interesting chip worth investigating.

Next actions:

• Wait until project is needed