- Joined May 18, 2020
Diolch yn fawr Ericbore da Allison,
As already pointed out, as the White LED require approx 3.2V forward voltage drop, you cannot drive 4 in series from 12V, use two pairs in parallel.
What do you think of the Circuit proposed by 'AnalogKid post #58 ??
Hi,If you have other parts, the circuit can be adapted. NPN's such as 2N4401, 3904, 2222, etc? PNP's such as 2N4403, 3906, 2907, etc? Logic chips: 74xx14, 00, 02, 32, etc? 555: do you have bipolar (LM555, NE555) or CMOS (LMC555, etc.)? I probably can do it with a 555 version with a PNP transistor if you have those parts already.
1. Can you expand on the timing between the two SENSE signals? As I understand things, both SENSE signals go low when triggered by an object, and S2 always is triggered *after* S1. Is this correct?
2. If so, then does S1 release (return high) always *after* the timer has finished its 10-30 second interval, *always* before, or sometimes either one?
3. If S2 has been triggered, does it return high *always* before the next triggering of S1? Or might S1 go low again while S2 still is low?
4. Does the POINT switch have to switch 12 V, or can it be connected to GND?
5. If the number of white LEDs can be reduced from 4 to 3, or increased to 6, things happen.
Depending on what the signals do and what parts you have, there are lotsa combinations that will work.
Would the following adaptation of your circuit diagram work ?