Harbor Freight Solar Node:

The goal was to create a self sustaining solar node for under $50. This was accomplished with the parts below. I have 2 of these nodes, one as a repeater that has no environmental sensor as I wanted to maximize the battery life and the other node acting as a temperature sensor.

Both have been working as expected for 2 weeks now. Just a warning, if you decide to implement the BME680 sensor you will have to get some custom firmware, as the XIAO nRF kit does not natively support I2C sensors with Meshtastic firmware.

For tree mounting:

I used black paracord and just tied knots in it after going around the tree once. This was done to minimize the effect of the node on the tree and allow the node to be easily removed for servicing or firmware updates.

Parts:

• SEEED XIAO nRF52840 & Wio-SX1262 Kit
  • [https://www.seeedstudio.com/XIAO-nRF52840-Wio-SX1262-Kit-for-Meshtastic-p-6400.html](https://www.seeedstudio.com/XIAO-nRF52840-Wio-SX1262-Kit-for-Meshtastic-p-6400.html)
    • $13.49
• Harbor Freight 40 lumen solar light
  • [https://www.harborfreight.com/40-lumen-8-in-solar-led-black-finish-spotlight-57704.html](https://www.harborfreight.com/40-lumen-8-in-solar-led-black-finish-spotlight-57704.html)
    • $8.99
• LORA Antenna (NOTE: ensure you choose the correct antenna for your region)
  • [https://www.aliexpress.us/item/3256808111627343.html?spm=a2g0o.order_list.order_list_main.11.58e2194dluRHqX&gatewayAdapt=glo2usa](https://www.aliexpress.us/item/3256808111627343.html?spm=a2g0o.order_list.order_list_main.11.58e2194dluRHqX&gatewayAdapt=glo2usa)
    • $4.55
• Battery BMS
  • [https://www.aliexpress.us/item/3256806228529707.html?spm=a2g0o.order_list.order_list_main.54.2b23194daV4UA9&gatewayAdapt=glo2usa](https://www.aliexpress.us/item/3256806228529707.html?spm=a2g0o.order_list.order_list_main.54.2b23194daV4UA9&gatewayAdapt=glo2usa)
    • $2.02 for 5
• 21700 li-ion battery
  • [https://www.18650batterystore.com/products/samsung-50e](https://www.18650batterystore.com/products/samsung-50e)
    • $2.75
• (Optional) BME680 Environmental Sensor
  • [https://www.aliexpress.us/item/3256804758381082.html?spm=a2g0o.order_list.order_list_main.5.1e41194dCw9zll&gatewayAdapt=glo2usa](https://www.aliexpress.us/item/3256804758381082.html?spm=a2g0o.order_list.order_list_main.5.1e41194dCw9zll&gatewayAdapt=glo2usa)
    • $5.66

Total Cost without shipping: $37.46 (w/ BME680) or $31.80 (w/o BME680).