Uchusen sun sensing breadboard setup Left-hand light sensor/LED Right-hand light sensor/LED Servo motor Serial printout w different values

Been working on a bare-bones sun sensing system here at Uchusen last week… which is helpful to know for your solar panels but also eventually for basic positioning, attitude change and spin rpm checks. As my soldering iron’s been refusing to play ball these last few days for my latest sensors just in, thought I’d get back to basics.

The breadboard was setup with two light dependent resistors hooked up to two analog channels, two LEDs programmed to light up if sufficient light shines on either LDR respectively, a smattering of regulation-issue 220-Ohm resistors, and a servo motor with spinning top to channel the LDR outputs and imitate a reaction wheel or similar pointing mechanism. Shone a light on one LDR then the other, the LEDs duly lit up and the servo motor made its turns as required (see COM12 output where val1 and val2 represent the incident light on the LDRs, measured from 0 to 1023 then rescaled for the servo motor to 180- or 360-deg).

Was a good refresher to mesh together separate chunks of code sitting in different sketches, although having to write a Serial.print(“sometext”) then another line with Serial.println(someval), instead of the more regular one-liner (“sometext”+someval) was rather ridiculous. Or maybe I missed something? Another interesting thing was that one LDR was abt 4x sensitive than the other: both came with Arduino starter kits albeit from different companies. As the light source was identical and the difference broadly similar under a number of incidence angles, assumed the sensors were different.

So now one step closer to finalising the first Uchusen PCB design that actually works electrically… next up the sensors!