Solar powered on/off line timelapse photography

Introduction

Create offline timelapse photographer power by solar power using Raspberry Pi. When the Raspi connects to the internet, it will start transferring the images to a net storage. The uploaded photos will be then shown on a separate web page. Also, by triggering GPIO pins, Raspberry Pi will send a separate photo directly to the net storage. These photos are used to adjust the position and alignment of the camera.

Connect to internet

My Raspberry Pi 4 uses WPA to store wifi and ethernet data at /etc/wpa_supplicant/XXXX.conf file. It includes

country=ee
update_config=1
network={
        ssid="My Phone"
        psk="very secret passphrase"
}

The internet connection can be shut down using sudo ip link set wlan0 down which mimics the procedure that my hotspot is not nearby. ip a or using ping you can verify that there is no internet connection. When connecting to back to internet [up] (or setting the hotspot on) everything should work. However, for some reason my Raspi did not connect to the internet, but by using sudo dhcpcd it works.

dhcpcd

Thus, I need to check if dhcpcd is working. This is easily done by checking /etc/resolv.conf file. If no internet is connected there is only a trivial nameserver ip address.

Note Iwconfig and ifconfig are deprecated.

Solar power

Things needed

• Solar panel
• Solar charging regulator (some panels include regulator)
• Battery: 12V or 5V power bank.
• USB car powered adapter

Or Solar power hat or Solar power module. Also, there exists batteries with included solar panel.

Battery

Size: 10000 mAh works 5 hours with 2 amps current. See https://learn.pi-supply.com/battery-levels/ for approximating time with different tasks.

Lead Acid: 12V or 6V. Need voltage regulator (or car USB) to bring the voltage down to 5V. Eg Texas Instruments LM2940T. 3 or 4 stage charge controller to protect the battery from overcharge. Assume 85% efficiency. . .

Li battery 18650: Use tp4056 charging modules for the batteries. ATtiny85 microcontroller for shutdown, see Solar powered Squirrel Cam.

Li-Ion: Cheaper but larger.

Li-Po:

NiMH: 4 times NiMH battery cells gives 100 to 200 mA. Use diode (eg 1A 40V Schottky) on positive wire between panel and battery so that the batteries wont lose energy at night through the panel.