I once connected an electrolytic in the wrong polarity, and it gave me horrible headaches until I realized my mistake. So yes, I can see why a polarized capacitor would be wrong for this application. On the other hand... electrolytics are bad for suppressing very quick transients, for that, small ceramic ones should be used... so maybe that's another reason for the circuit's behavior.

It's all about the frequency.

<Off Topic> When I was a kid I got a big bag of surplus 8uf polarized electrolytic capacitors. Keep in mind, when I was a kid was just following the ice age. My father had just finished the attic into two bedrooms one for me and one for my 2 sisters. He wired a few switched outlets where the night tables were beside the beds. My sister had her lamp on the table plugged into a switched outlet. With power off I would carefully place a cap across the outlet, poking the cap leads into the outlet slots. My sister would walk in the room at night, flip the wall switch on and give it a few seconds and BANG! Those little caps went off like a good firecracker. </OFF TOPIC>

Ron

 

It's all about the frequency. Ron

<OFF TOPIC> Naughty boy, you... </BACK TO TOPIC>

 

I once connected an electrolytic in the wrong polarity, and it gave me horrible headaches until I realized my mistake. So yes, I can see why a polarized capacitor would be wrong for this application. On the other hand... electrolytics are bad for suppressing very quick transients, for that, small ceramic ones should be used... so maybe that's another reason for the circuit's behavior.

Guys, I don't know about the rules, and I don't know if the electrolytic polarity is correct for this circuit, but I've got 24ish hours of observing the post 15'd breadboard and... no false triggers. Rock solid. Works! Now if it works, don't fix it I might contribute! We can reason later as to why it works, would definitely be a stimulating conversation. I'm going with EMI as cause of spurious firing on my very uninformed non shielded wiring... tell me what would the unshielded wiring do to the piezo buzzer?

 

Guys, I don't know about the rules, and I don't know if the electrolytic polarity is correct for this circuit, but I've got 24ish hours of observing the post 15'd breadboard and... no false triggers. Rock solid. Works! Now if it works, don't fix it I might contribute! We can reason later as to why it works, would definitely be a stimulating conversation. I'm going with EMI as cause of spurious firing on my very uninformed non shielded wiring... tell me what would the unshielded wiring do to the piezo buzzer?

To the buzzer? nothing, since it's a one-way output. But long unshielded cable to the switch is a big no-no.
What did you do? Did you only change the capacitor to a non-polarized type? Or did you also changed the wiring to the switch?

 

To the buzzer? nothing, since it's a one-way output. But long unshielded cable to the switch is a big no-no.
What did you do? Did you only change the capacitor to a non-polarized type? Or did you also changed the wiring to the switch?

I only switched the resistor like in post 15, with electrolytic polarity as in post 15

This is on breadboard uses a pushbutton switch

 

I only switched the resistor like in post 15, with electrolytic polarity as in post 15

This is on breadboard uses a pushbutton switch

This was the 'does it happen on the bench aswell test'

 

I only switched the resistor like in post 15, with electrolytic polarity as in post 15

This is on breadboard uses a pushbutton switch

So you're using the circuit exactly as shown in post 15? And now you need to test it connecting it to the reed switch?

 

So you're using the circuit exactly as shown in post 15? And now you need to test it connecting it to the reed switch?

I did test exactly like post 15 with long reed wires already... spurious firing... pretty sure it's emi 'cause with breadboard wires - same circuit- I get no fault

 

I did test exactly like post 15 with long reed wires already... spurious firing... pretty sure it's emi 'cause with breadboard wires - same circuit- I get no fault

So there were TWO causes for the spurious firing?

 

Umm, yes. The change of post 15 fixed the bench breadboard's spurious firing and after I fixed the veroboard up with post 15's changes, EMI still gave me spurious firing on the veroboard unit, I'm going to fix the veroboard into a small lunch box that would sustain the elements mostly... and rewire accordingly the reed and the buzzer (using 9v pp3 as power source)

 

Umm, yes. The change of post 15 fixed the bench breadboard's spurious firing and after I fixed the veroboard up with post 15's changes, EMI still gave me spurious firing on the veroboard unit, I'm going to fix the veroboard into a small lunch box that would sustain the elements mostly... and rewire accordingly the reed and the buzzer (using 9v pp3 as power source)

So you're going to use a shorter wire for the reed, and a longer one for the buzzer? If you do that, the only side effect would be that the buzzer's volume might sound a bit lower... other than that, things should work out...

 

I did test exactly like post 15 with long reed wires already... spurious firing... pretty sure it's emi 'cause with breadboard wires - same circuit- I get no fault

I agree. The use of shield wire may eliminate that or as you mention move things.

Ron

 

So you're going to use a shorter wire for the reed, and a longer one for the buzzer? If you do that, the only side effect would be that the buzzer's volume might sound a bit lower... other than that, things should work out...

And the psu is 9v vs 12v I had inside (also lower volume), but it's an exceptionally loud buzzer, something like 110db at 1m at 12v, so that's no problem at all

 

When you're finished, let us know how it went... then we can celebrate with a main street parade and evening fireworks...
nah... I'll settle for a beer...

 

I dunno if I should wait for the handyman comes Monday - let him do the rewiring, or do it self tomorrow (sun has gone down already) dunno if I'll be able to wait that long, but he might do a better job... I hate wiring :-(

 

And the psu is 9v vs 12v I had inside (also lower volume), but it's an exceptionally loud buzzer, something like 110db at 1m at 12v, so that's no problem at all

The wire is insulated, if I run it along the pole of the gate, the gate's not gonna become an antenna? only if it's not insulated?

 

The wire is insulated, if I run it along the pole of the gate, the gate's not gonna become an antenna? only if it's not insulated?

When you say insulated do you mean shielded?
When you install shielded cable, ground only ONE of its two ends... if you ground both you may cause an undesirable ground-loop which will be just as bad as EMI

 

When you say insulated do you mean shielded?
When you install shielded cable, ground only ONE of its two ends... if you ground both you may cause an undesirable ground-loop which will be just as bad as EMI

No just insulation, just a bit of plastic covering the 25m jumper cable
and to make emi worse the excess 10m on each wire is a coil

I don't have any end grounded, just 2 sides of the reed

 

No just insulation, just a bit of plastic covering the 25m jumper cable
and to make emi worse the excess 10m on each wire is a coil

10m is still too long... cable length should be no longer than 2m

 

10m is still too long... cable length should be no longer than 2m

25m jumper + 10m coil is the (now offline) reed cable
I don't have any wire grounded, just 2 ends of the reed switch, should there be grounding?
gonna install new wiring Mon