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Making a Digital Anemometer with Raspberry PI Zero
I want to make a digital anemometer with raspberry pi zero. The idea is to left the device in the wild and this device must send back to me reads of wind velocity and direction remotely vía cell modem.
In other words, the device must have:
- Solar panels and a battery: the device must be self-powered
- Some kind of power management: to stabilize the power of the battery and adapt it to the raspi and to the modem
- A hsdpa modem: to provide internet connectivity
- Some SBC: raspberry pi zero is a great candidate
Making some calculations
I need to guess how much power the raspberry pi plus the modem will consume.
|Raspberry Pi Zero||120 mA (0.7W)||from (here)|
|Hsdpa Modem||120 mA||(estimated)|
The approximate consumption of this set is 240ma. For powering it, I've think that the PowerBoost 500 Basic - 5V USB Boost @ 500mA from 1.8V+ will draw enough power for it.
For the batteries, the circuit can have NiMH batteries or lipo batteries. I've think that NiMH batteries are cheaper and safer, so I decided to use them. Aproximately 7.200 mah will keep the weather up and running for more than 24 hours, which is convenient in case there is a cloudy day. Two NiMh C batteries will do the job.
Next, is the cell panel. A tough question. Do it correctly needs measures of solar power in your zone, estimations of the productivity of the solar panel based on this and a lot of things. But! I don't have the knowledge nor the time for it, so I decide to use this: https://es.aliexpress.com/store/product/5pcs-lot-Solar-Panel-Portable-Mini-6V-1W-Sunpower-DIY-Module-Panel-System-For-Solar-Lamp/1960862_32819874146.html, joining as many panels as needed. Just an exercise of trial and error.
The anemometer is pending.
I have spent 77€ so far now.