☀️ Circuit diagram for a solar-powered LoRa node

A circuit diagram for a solar-powered LoRa radio node, including a solar panel and battery. The text reads as follows: Iffy Books / Let’s Make a Solar-Powered Chat Network / 5V 6W monocrystalline solar panel / 100 nF ceramic capacitor / 100 uF electrolytic capacitor / MCP1700-3302E LDO regulator (flat side facing forward) / TP4056 battery charger w/ protection circuit / USB-C cable / 18650 lithium-ion battery / Heltec LoRa32 V3 w/ antenna

We’ve been hard at work running tests and writing documentation for on our upcoming workshop Let’s make a solar-powered chat network, in which we’ll build weatherproof LoRa nodes running Meshtastic to support a long-range encrypted chat network. Twenty participants will get free solar chat node kits, thanks to a grant from the Engaged Humanities Studio program at Swarthmore College.

Stay tuned for a how-to zine, which we’ll post as a PDF in the next few weeks. In the meantime, here’s a complete circuit diagram for the project:

➡️ Circuit diagram for a solar-powered LoRa radio node

We tested a many different voltage regulator circuits that didn’t work out, and we ended up adapting a project on Random Nerd Tutorials for our final design. Note that we’re powering the LoRa32 at 3.3 V, which requires soldering wires to the pin holes. (For a temporary setup, you can run wires through the pin holes and attach with tape.)

Here’s a list of parts we’re using:

• Heltec LoRa32 v3 w/case
• 5V 6W monocrystalline solar panel
• TP4056 battery charger module w/ header pins
• 18650 lithium-ion battery
• Battery clip
• MCP1700-3302E low-dropout (LDO) regulator
• 100uF electrolytic capacitor
• 100nF ceramic capacitor
• Micro breadboard
• 1.25mm JST connectors
• DuPont jump wires
• USB-C cable
• USB extension cable
• Heat shrink tubing
• A weatherproof enclosure

Registration for our solar chat network workshop filled up fast, so we’ve scheduled an overflow workshop on Sunday, May 14 at 1:00 p.m. (which isn’t free but covers the same material).