The fine dust sensor as a unit needs approx. 1 Watt, if it would run through the whole year, that would be (1W x 24h x 365 days)/ 1000 = 8,76 kWh, so approx. 2,50€/ year.
Dump the usb to serial chip, LDO regulator (use a switching regulator) and the leds and I have it down to 0.5W…
How do you dump the usb to serial chip? Are you just physically disconnecting it on the board, same for the LEDs…
If you remove the serial chip depending on the board you might need to remove a couple of transistors used to put the device into programming mode.
Could you elaborate on that? Let’s say you’d want to power this unit with the SDS011+SHT31, but wanted the lowest power usage possible.
What part(s?) do I remove from the board?
And I would also like to know what the Voltage input range requirement is for proper functionality.
Min and Max V, and expected power usage. This should also be made clearer for the USB input, because my guess is many are feeding it with solar power;
How stable does the V need to be? Officially the USB 2 spec has a +/- 5% allowance, so it should be designed to accept 4.75V to 5.25V. Is that indeed the case?