Solar panel with LM317 regulator for micro:bit power

Customer:

I’m working on an energy-efficient smart home project with a micro:bit controller. I’ve tested a PIR sensor with the micro:bit and it works well. Now I’d like to add an LED strip for lighting in the house model (under half a meter long) that can be controlled on and off via the micro:bit. I also need to know if you have solar panels that could power the micro:bit instead of using 3V batteries or USB power.

Original message (Croatian)

radimo trenutno mali projekt sa micro:bit kontrolerom gdje nam je želja napraviti energetsko štedljivu kuću. Naime za potrebe projekta smo nedavno u Vas naručili PIR senzor i testirali sa micro:bit-om. Ono što nam je sljedeće interesantno i molimo Vas za savjet; da li možemo spojiti neku led traku u funkciji rasvjete u modelu kuće (ne treba biti veća od pola metra) tako da bude upravljano paljenje i gašenje led trake preko micro:bita i da li imate neke solarne panele koji bi mogli napajati micro:bit-ove umjesto 3V baterija i usb priključaka?

Originally submitted via email support on 8 June 2017. Migrated to the forum for community visibility.

Soldered Support:

We have a solar panel that can output up to 9V depending on the amount of sunlight. We don’t have a ready-made 3V regulator, but you can build one yourself using an LM317. See the datasheet at Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics. To set the output voltage to 3V, use resistors: R1 = 240R, R2 = 410R.

Original message (Croatian)

isprike na kasnom odgovoru. Ovisno o količini sunčevog zračenja davati će do 9V izlaz. Nažalost nemamo gotov regulator na 3V, mogli biste sami napraviti ga s LM393: https://e-radionica.com/hr/lm317-podesivi-regulator-napona.html Pogledajte datasheet: Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics Kako biste podesili izlazni napon na 3V otpornici trebaju biti: R1 = 240R, R2 = 410R.