Hi,

I am trying to build a circuit that uses an IR sensor to trigger a solenoid. When the IR sensor is triggered, I need a 30 second delay before the solenoid is triggered. Also, if the IR sensor is triggered again before the 30 seconds are up, I need the timer to reset to 30 seconds. Currently, I am using an IR sensor, a 555 chip and a solenoid. Do I only need 1 555 chip and what resistors/capacitors do I need to program it to delay for 30 seconds? Thanks in advance for any help someone can offer on this project.

 

Everyone will want to see your circuit diagram (schematic) before responding in substance. As for general advice, get the IR detector part working first. Once you have a reliable signal and no false signals, making the solenoid drive will be straight forward.

John

 

555 monostables are not retriggerable as far as I know. You will probably need to use a retriggable monostable such as: 74HC123 (5V) or CD4528 (<18V).

Ken

 

how do u test to see if an IR detector is working?

 

We need to see your circuit. Presumably, your detector gives a high or low logic (or similar change) with detection. Monitor that signal and be sure it is what you need. John