It might be possible to power the Arduino off the output pin. Since they are dirt cheap I would just test it.
But like the others I would suggest to use the interrupts of pin 2 and 3.
For my battery powered 3.3v pro mini I use 3.3v pir sensors without the voltage regulator. The standard 5v pir needs at least 4.5v just to step it down internally to 3.3V. On these I had problems with voltage stability because I stepped it up to 5V. Also the battery lifetime was poor.
With the 3.3v pir version this thing runs for months. With the solar panel on top maybe forever.
For those of you who want an extremely simple build, I've reduced it to just 5 parts:
one 1-megaohm resistor (0805 SMD)
one Arduino Pro Mini
one Ra-01 LoRa module
Male header pins
Battery clips
See photos.
@jvdk I agree with the point made by @evb , why would you want to wire connect the ultrasonic node rather than the usual radio connection ? You are adding levels of complexity and power demands for what reason ?
My ultrasonic water tank node (pro-mini+rfm69) is now 2 years on the same 2xAA batteries sending in levels every hour (RTC), the only problem encountered - condensation forming a drip on the face of the ultrasonic head during very low temperatures.
@Nca78 said in Dimmable LED kitchen light (Arduino, APDS-9960, RGBWW led):
Do you use a relay to control the leds or still a MOSFET ?
i'm using mosfets.
