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Beginner Question 555 possibly monostable

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pdistance

New Member
Hi, I have tried to find a simple answer for this in the forum but would appreciate if someone could give me a pointer. I set out on a project to try and move a 3mm diammeter rod in direct proportion to a voltage applied but I was limited to very small components and couldnt find a stepper motor with linear movement control which was less than 1.5cm long and required low voltage dc supply. The only other option I could find was to get a miniature solenoid and use a simple on off trigger and use a mechanical screw to adjust position after initial on trigger. I am using a mechanical on off switch to apply a trigger to activate a solenoid using the smallest battery available probably a 6v camera battery. The problem is that I need the solenoid to be activated after a period of time rather then immediately when the switch is closed ~(or open if need be). This delay has to be confirmed but will be between 0.1 - 0.8 secs. I was thinking of a switch which triggered a 555 timer output after eg 0.5 secs , the output goes high to activate the solenoid and stays in the high position.
So
1 - switch is closed
2 - A 0.5 second delay occurs before
3 - A battery voltage is applied to a solenoid and stays there until switch is open

4?? does anybody know of a tiny linear low voltage dc stepper motor available as I couldnt find one
Any help please....
 
Last edited:

robadobalus

New Member
Hello,

Probably not the right way to do it but could you put a capacitor in your circuit somewhere to provide your time delay. So effectively you have to wait for the capacitor to charge up before the solenoid would move? If not a 555 timer would do the job. Let me know if you need a circuit diagram and or the formula's to calculate the capacitor and resistor values.

Rob
 

KMoffett

Well-Known Member

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thecritic

Member
That power delay circuits helped me too. But I didn't see any resistors that would discharge the capacitor after it has been charged so that it would function next time also.
 
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ericgibbs

Well-Known Member
Most Helpful Member
That power delay circuits helped me too. But I didn't see any resistors that would discharge the capacitor after it has been charged.
Hi,
If you mean Ken's circuit, the capacitor is discharged via D1 and R1.
 
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