Light triggered LED

Im making an array of LEDs connecter to LDRs. im having trouble decicing on what chip to use. i want the chip to read that a LDR has been triggered read that data and send it to the corresponding LED, but i dont want to end up using more the 10 chips any sugestions as to what chip i should use

Im making an array of LEDs connecter to LDRs

We seem to be missing an at least one important item of information here.

AWOL:
We seem to be missing an at least one important item of information here.

Yes, what he actually proposes to do.

I don’t care what s/he wants to do, but it would be nice to know how many time s/he intends to do it.

As much as s/he has described so far, this has nothing to do with Arduinox. That in itself is not a problem; we don't entirely mind, but either way, the information is entirely insufficient to describe the proposal.

Im building a laser trainer there will be about 150 leds paired with 150 LDRs im using an arduino to for different "game" modes and when a LdR is triggered i want the paired led to stay turned on, and to flash when its triggered twice

OK, so next you need to describe how many of the 150 LDRs you wish to have near each other so that you can use one device to control them and their respective LEDs. This defines the use of an ATTiny, an ATMega328 or a Mega 2650 for each unit.

Given the paradigm, LED on when hit, flash when triggered a second (or subsequent) time (how many flashes, for how long?), what is the "reset" condition that turns the LED off again?

Are you sure you want LDRs? Might you instead want 38 kHz photo-diode modules that are sensitive to 38 KHz modulated light (including lasers) rather than ambient light?

its a 7inch circle with three rings and 36 sections on the first ring 18 on the second and one in the center. there are 3 LEDs And 3 LDrs pre section layed out as shown in the picture. for the reset it is another LDR acting as a switch and when triggered it resets the LEDs this is off to the side and seperated from the main circle. i did think of using photo diodes but in testing the LDRs have been working.

As for flashing right now its programed to stay on when it is first triggered, and any time after that if will turn on and off 3 times and continue to stay after flashing. and im currently working with an uno

OK, that all makes sense. So I calculate that as 55 sections, so 55 outputs and 56 inputs. I see no particular reason each three LDRs cannot be simply wired in parallel and similarly for the LEDs, though there are other ways of doing it.

How about a Mega 2560 to sense the LDRs - note there is no need to use analog inputs - if you have the resistor correctly chosen, a digital input will switch at a certain light level. It will be easiest to read the LDRs without multiplexing and they can be read as groups of eight.

As to the LEDs, 56 is seven times eight; so seven TPIC6B595s could be used to control 56 groups of three series LEDs powered from ten to twelve volts (depending on the colour). You can them power the LEDs with as many mA as they will take (though if this is in any form of darkness, you will not want much).

You could arguably do the job with about four Pro Minis and seven TPIC6B595s; you have to figure which is cheaper. (If using clones, this would actually be the cheapest.)
led ldr layout.jpg

Paul__B:
I see no particular reason each three LDRs cannot be simply wired in parallel and similarly for the LEDs, though there are other ways of doing it.

led ldr layout.jpg

[/quote/}

Wouldnt doing that cause them all to light up evn if only one is triggered

Wrong brace!

steches:
Wouldn’t doing that cause them all to light up even if only one is triggered

Yes, I rather assumed that would be appropriate, to illuminate a complete sector it a hit is made to that sector.

No its just divided in to sections like that to make it eaiser to map out only a single led will light up when "hit"

Oh well, multiply by three then.