$50 robot photoresistor math

[pomprocker]

I am trying to do this photoresistor math.

In the darkest operating light I am have the dial set at 200k and i'm geting a reading of 80.00

and set at 200k in a spot of sunshine coming in through the window I am getting 00.23

This give me 4.2 after the equation?

So should I use a 4.3k resistor?


I originally tried it out with just using the 1.62k resistor that was listed in the parts on the tutorial, but not getting very good results.

[Admin]

80.00 what? kohms? and .23 kohms?

Make sure your units are correct.

sqrt(80k*.23k) = 4289.5 ohms

sqrt(80*.23) = 4.3 ohms

[pomprocker]

80.00 what? kohms? and .23 kohms?

Thats what i'm trying to figure out. All I know is the multimeter was set in the 200k range and the display just said 80.00 or 00.23

[Admin]

Go with the 4.3k, the other one is waaaay too low.

[superchiku]

man if the multimeter was at 200 then it is reading 80k,
u shouldknow about the multimeter first its the basic and one of the most reliable devices