Re: [mowbot] Colour sensor

robin nospam at
Tue, 5 Nov 1996 20:50:34 GMT

Monta wrote:
> What distances have you tried;
> a few (6?) centimeters should be enough.
So far I have only tried very controlled conditions to prove the concept.

I had the LDR and LEDs stuck in a breadboard underneath one of those empty
black plastic film canisters with a hole cut in its end. I then
presented the targets right on top of the hole, about 2cm away from
the LDR:
_____________________coloured sample
^ #### ####
| # #
| # #<-- film canister with hole in end
55mm # LED LDR #
| # | | | | #
V # | | | | #
======================================= breadboard

I see no reason why it shouldn't work over much greater distances.
However, more light leakage from outside and reflection from uninteresting
items will probably mean that better amplification and doing the
trick with modulated light will become necessary. That'll be my next


Copyright (C) 1996 R.M.O'Leary <robin nospam at>  All rights reserved.
For licence to copy, see