Roff
Well-Known Member
What LDR circuit are you testing?djpubba said:No it should shift the minimum voltage from the pot by 0.5V thus giving you about 1 V min as you want. it will also shift the max voltage a bit.
I tested it before saying that. It doesn't shift by any significant value. It just crops it to 1v. So I get 1.0v far left as desired but center and far right are the same as before the change -- no shift.
Not knowing what I'm doing, I decided to try making a resistor ladder between 0v and +5v to get +2.5v and fed that into the -5v pin on the Vectrex controller so that my input voltage range would be +2.5 to +5 instead of 0 to +5, hoping that would shift my output voltage range. It did something completely different than I expected. It gave me +1.3v on the far left, +1v center and +1.6v far right. :shock:
Ron's point re the LDR delay and the open loop issue is relevant. So it may not work very well. I had not looked at a LDR spec, so missed this point.
Judging from how the game controls with the LED/LDR circuit, the response time is more than adequate for proper gameplay. It's just in the wrong spot -- the right side of the controller.
I'll still try Ron's circuit.