It's been a few years since I did any significant electronics in my shed/ w orkshop. But I'm going to have to get stuck in again because I need to rede sign my light sensing circuits. I've used LDRs in basic voltage divider cir cuits (with hysteresis) for the last decade or two for garden and porch lig hts etc. But they need attention with annoying frequency, because of LDR de terioration. The ratio of R(dark)/R(light) drops too low. For a while I can adjust the switchover voltage with the preset, but even that soon becomes impossible.
To keep work to a minimum, I'm wondering if there is any photodiode-based c ircuit that I could simply substitute for the LDR? Failing that some relati vely simple changes? Or some other modern but easily accessible component I could use?
Does anyone else have similar problems? If so, have you found any practical solutions?
Any suggestions would be much appreciated please.
Terry, East Grinstead, UK