Some help needed for a circuit idea for a project (Using LDRs and 555 Timers)

[cmcmanus8]

Hey everyone,

I'm new just joined tonight . I had an idea for a circuit for this project I'm doing and I was just wondering if it would work and is the best way to do so.

I was planning on having an LDR circuit which - when it was dark - would trigger a 555 timer in monostable operation to then trigger a 555 timer which was in astable operation?

I'd be needing the astable 555 timer to turn on for roughly 2 seconds, off for 16 seconds, then back on for 2 seconds then just switch off permanently. So I was hoping to do this by having the monostable 555 timer turn on for around 20 seconds. Is there an easier way to carry out this and would it work??

 

[MikeMl]

Welcome,

What is the LDR resistance? When illuminated? When dark?

 

[cmcmanus8]

Ahh I haven't actually chosen that yet, I was planning on going into my labs tomorrow to check what all was available. It was pretty much a rough idea and I was just checking whether it would be worth going ahead with it as I've quite pressed for time to complete it. I used a 555 timer calculator to figure out that I'd need the following value components.

Astable 555 - 2.2μF capacitor, 10MΩ and 1MΩ resistors
Monostable 555 - 2.2μF capapacitor, 1MΩ resistor