I've personally installed these things in cheap solar garden lights, set up outdoor repeaters that have weathered the Canadian winter with only solar power, and attached a screen & keyboard to create an off-grid communicator that'll run for days on a single charge.

It's been extremely easy to test these boards in almost any of the conditions in which I plan to use them, because powering them is as easy as attaching just about any DC power source I have on hand, with or without a battery, thanks to the BQ25185 chip managing the power input! I've even been able to test solar panels indoors just by pointing a bright LED work light at whichever panel I want to use, and the status LEDs give me immediate feedback for whether or not it's a valid power source, and whether that power source is capable of charging the battery.

No matter how you decide to use it, you have access to a wide range of features:
  • USB type C input with configurable charge rate limit (250mA, 500mA, 1A)
  • LiPo/LiIon and LiFePO4 support
  • ESD/TVS protection on the USB input
  • Flexible DC input, including MPPT-like solar support, from 3.3V to 18V
    • Includes a JST PH connector, as well as pads for soldering directly!
  • Will recover from brownouts and dead batteries without physical intervention
  • Smart power path management, thanks to the BQ25185. No need to worry about unnecessarily cycling the battery!
  • JST 2.0 and Picoblade 1.5mm battery connector footprints, to hopefully fit whatever LiPos you've got laying around
  • Low operating power, measuring as low as 28mA idle current draw (running Meshtastic on CLIENT mode, without WiFi)
  • Active current/voltage monitoring and reporting on 3 channels over the mesh, via INA3221
    • Ch. 1: Battery
    • Ch. 2: USB & external power
    • Ch. 3: BQ25185 regulated output (essentially the entire board's power consumption)
  • Up to 8MB onboard flash, perfect for hosting a BBS or Meshcore room server
  • WIO-SX1262 LoRa radio
  • BME280 temperature & humidity sensor
  • I2C expansion pins
  • External notification output, driven by a MOSFET for loud buzzers & bright lights
  • User button input
  • Optional Raspberry Pi RM2 module for WiFi & Bluetooth
  • Total footprint size of ~42*32mm, less than half the size of a credit card!
This project is sponsored by PCBWay! Huge thanks to them to making this project possible to continue. They were generous enough to reach out and help give me the opportunity to test out the final revision of this board, and in doing so, I had the chance to try out their turnkey PCB assembly process, which was instrumental in getting this revision out the door.

Every time I've used them, their boards have always come out near perfect, and these ones are no exception. Their engineers were in contact with me from start to finish, making sure that everything was correct and to spec throughout each step of the process. They sourced all of the parts based on the BOM I provided, ensured that each pick lined up with what I needed, and even sent confirmation photos before the assembly process to ensure that every part was placed & oriented properly. When I mistakenly selected two parts to fit a single footprint, they agreed with my request to ship me the extra parts that I had them order alongside the PCBs, for me to solder by hand if needed after I receive them! They even double checked some mixups between part numbers I provided that didn't quite match up with the part description, and made sure the substitution would not be a problem before ordering them.

Overall, I'm super happy with the quality of their work, and now that I've been able to torture test these Meshlet boards with the classic green silkscreen, I look forward to ordering more in the many different colour options they have available! I'm particularly fond of their matte black and purple options.

Project files are all available on GitHub, with more details on the Meshlet webpage over on my website!