I keep looking at this thing and thinking about it. The 555 looks to be configured as a one shot. The only thing the cap on pin 2 is doing is acting as a switch debounce as I see it. The cap could be eliminated and it likely wouldn't matter. Here nor there. The only way the 555 can trigger is if the voltage on pin 2 (Trigger) drops below 1/3 of VCC. Just to see what happens I would eliminate the cap and make the resistor to pin 2 a 10K pullup. See what happens. A decoupling cap on pin 8 of 22 uf should be more than adequate. The Reset is tied to VCC so it isn't going anywhere. So I see no easy way for the trigger voltage to drop below 1/3 of VCC unless for some unknown reason that cap momentarily breaks down. Thus I suggest eliminating it. The only other remote thing I see causing maybe a problem is a glitch in the power supply VCC and that is remote. Good decoupling was mentioned earlier. What else is there?

Ron

 

I keep looking at this thing and thinking about it. The 555 looks to be configured as a one shot. The only thing the cap on pin 2 is doing is acting as a switch debounce as I see it. The cap could be eliminated and it likely wouldn't matter. Here nor there. The only way the 555 can trigger is if the voltage on pin 2 (Trigger) drops below 1/3 of VCC. Just to see what happens I would eliminate the cap and make the resistor to pin 2 a 10K pullup. See what happens. A decoupling cap on pin 8 of 22 uf should be more than adequate. The Reset is tied to VCC so it isn't going anywhere. So I see no easy way for the trigger voltage to drop below 1/3 of VCC unless for some unknown reason that cap momentarily breaks down. Thus I suggest eliminating it. The only other remote thing I see causing maybe a problem is a glitch in the power supply VCC and that is remote. Good decoupling was mentioned earlier. What else is there?

Ron

The cap on pin 2 is there so that the reed switch can remain active, but doesn't produce sound for as long as the switch is active, otherwise the buzzer doesn't stop, it goes on forever, and I need the gate to open, 6/7seconds of buzzing, until the gate is closed and opened again and not the entire time the gate is open

 

but then the negative of the electrolytic goes straight to live? (well through R2, but it goes to live)

You're right!... leave the positive of the cap connected to R2! as was "mistakenly" drawn in your first draft.

 

You're right!... leave the positive of the cap connected to R2! as was "mistakenly" drawn in your first draft.

but the mistake, luckily didn't appear in my veroboard mask, there I had it right from the start, SOOO, what is the error, is 22uF enough for between ground and Vcc, or am I only going to fix it if I implement one of your designs... which one's your favourite... unless we can fix my implementation, I guess starting from scratch would be the only way

 

but the mistake, luckily didn't appear in my veroboard mask, there I had it right from the start, SOOO, what is the error, is 22uF enough for between ground and Vcc, or am I only going to fix it if I implement one of your designs... which one's your favourite... unless we can fix my implementation, I guess starting from scratch would be the only way

No, you don't need to start from scratch, just add the 22uF cap between the ground pin and Vcc pin, AND correct the way the trigger cap is connected, also correcting for polarity.

 

No, you don't need to start from scratch, just add the 22uF cap between the ground pin and Vcc pin, AND correct the way the trigger cap is connected, also correcting for polarity.

PLEASE just have a look at my veecad mask, everything works already, just random false buzzing. false buzzing Also AFTER I connected the 22uF, who's wiring I'd like you to check on the veecad mask

Ps I would post it (buzzer8_veecad) again, but eskom just cut our electricity, usually for about 2h... so this is my phone

 

PLEASE just have a look at my veecad mask, everything works already, just random false buzzing. false buzzing Also AFTER I connected the 22uF, who's wiring I'd like you to check on the veecad mask

Ps I would post it (buzzer8_veecad) again, but eskom just cut our electricity, usually for about 2h... so this is my phone

Ok, I just looked at that file again, and your trigger cap is still left floating when the reed switch is left open. You need to change that.

 

Ok, I just looked at that file again, and your trigger cap is still left floating when the reed switch is left open. You need to change that.

But 2 where without losing its function as barrier to keep from eternally buzzing? It makes sense that a floating cap like that would be intermittent, but wont connection to ground make me lose it's function?

 

But 2 where without losing its function as barrier to keep from eternally buzzing? It makes sense that a floating cap like that would be intermittent, but wont connection to ground make me lose it's function?

Ah... I see what you mean, let me check again and BRB

 

The way I showed you how to hook it up in post #15 shouldn't change the way it's been working for you so far. Pin 2 would still be pulled up, and it won't be until the reed switch closes when the circuit will be activated.

 

The way I showed you how to hook it up in post #15 shouldn't change the way it's been working for you so far. Pin 2 would still be pulled up, and it won't be until the reed switch closes when the circuit will be activated.

So where lies the voodoo? We're using a magnet that holds your lighter without dropping it, I'm pretty sure no amount of me shaking the gate could produce a false buzzing, I tried, open buzz works as expected, and not quite sure why, but closing also triggers, and at a reasonably low frequency: completely random triggers

 

So where lies the voodoo? We're using a magnet that holds your lighter without dropping it, I'm pretty sure no amount of me shaking the gate could produce a false buzzing, I tried, open buzz works as expected, and not quite sure why, but closing also triggers, and at a reasonably low frequency: completely random triggers

Maybe I misunderstood your problem... you're saying that you want it to stop triggering when closing ?

 

Maybe I misunderstood your problem... you're saying that you want it to stop triggering when closing ?

If that is the case then you need to add an RC filter to the switch, since it's probably bouncing when it either opens or closes, and that's what's causing your problem

 

Maybe I misunderstood your problem... you're saying that you want it to stop triggering when closing ?

I thought it might be bouncing, and have no trouble with it, just wasn't sure why, but bounce is what I thought. I have trouble with the completely random triggers, THAT'S the voodoo

 

I thought it might be bouncing, and have no trouble with it, just wasn't sure why, but bounce is what I thought. I have trouble with the completely random triggers, THAT'S the voodoo

So it also triggers while the circuit is at rest, right? meaning that it will trigger on its own even when you're not opening or closing the gate, right?

 

So it also triggers while the circuit is at rest, right? meaning that it will trigger on its own even when you're not opening or closing the gate, right?

EXACTLY the problem, any ideas?
and I vigorously shook the gate, it's a heavy duty magnet 4 or more times the size of that small magnet that's in the white box you get with your small white box with the reed switch in. So I'm pretty sure no error will occur with the reed switch

 

EXACTLY the problem, any ideas?

Then post #15 should solve that problem. Though you may still need to add an RC filter if you also want to debounce it while opening and closing.

 

Then post #15 should solve that problem. Though you may still need to add an RC filter if you also want to debounce it while opening and closing.

Debounce not a priority, I'll check 15 again when power is back on, it's also single shot and not eternal buzz?

 

Debounce not a priority, I'll check 15 again when power is back on, it's also single shot and not eternal buzz?

Yes, it should work just fine.

 

Yes, it should work just fine.

Post 7 or post 15?