Anyone tried building the zvex probe circuit?

[tss]

I tried building it based on this site schematic http://4.bp.blogspot.com/_y4AYtND8Hz8/R-D1JQQcF9I/AAAAAAAAAKI/upWnOEC87_g/s1600-h/vsex_probe.jpg
However does not work at all! Doesn't do anything at all to the LED....

Here is my schematic (I know the voltage says 5V, however I hooked it up to 9V)


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[Hides-His-Eyes]

I've always wanted to give it a go... Sure you've got the 2n3906 in the right way round?

[tss]

Yes, I believe everything is hooked up correctly. However the circuit does nothing...?

[The Tone God]

Hmmm...I don't really like that circuit too much for a number of reasons. I think DIYers are going to have a hard time getting to work consistently.. Just to start things off are you really sure that circuit is using a 4093 ? From that design I don't think it is or atleast I don't think that is the best IC for this circuit.

Andrew

[deadastronaut]

yep...tried this a while back, in fact i tried a few 'proximity sensors....with varying poor results..

a lot depends on the size of 'plate' you have...and a few other variables...like wearing socks and not shoes etc...

i couldnt get it to work really...i used a 4093ube IIRC...very fussy circuit...

me and a guy on here called 'clydeshere' went through it!...

http://www.diystompboxes.com/smfforum/index.php?topic=88019.0

and

http://www.diystompboxes.com/smfforum/index.php?topic=88241.0

[earthtonesaudio]

It works but like all capacitive sensing proximity circuits you have to be careful about antenna construction.

The reason this circuit is problematic for DIYers is that the schematic alone is insufficient to build a working clone.  You also need the geometry of the antenna and ground plate. 

FYI the purpose of the 5V zener is I believe intended to keep the proximity circuit stable in spite of varying battery voltage; if you use a regulated 9V supply you can run it at 9V for (perhaps) slightly better performance.

[The Tone God]

Well anyone with basic logic gate design will recognize that the configuration of the oscillator is not really the best for a 4093 which is why I question if it is a 4093. Other gates use that setup. Did whoever drew this build it with a 4093 and compare to the original ?

Even if it is correct it still is a poor design for DIYers. Power supply would be one issue but the circuit is designed to be matched to the hardware. One of the reasons I've held off releasing a design I just know that no matter how specific I am in the design I'm going to get hammered with questions on why it doesn't work and alot will have to do with the hardware design of the antenna. Another thing I don't like is it seems the 3906 is adjusting the frequency of the clock. I don't like that idea at all.

I could go on but won't.

Andrew

[deadastronaut]

yeah i'd rather stick with light sensor types..... instead of the proximity...

they all have there drawbacks though!..daylight/night etc....but at least you can wear shoes..

[Paul Marossy]

It works but like all capacitive sensing proximity circuits you have to be careful about antenna construction.

The reason this circuit is problematic for DIYers is that the schematic alone is insufficient to build a working clone.  You also need the geometry of the antenna and ground plate. 

Yeah, I could see how that would be the case.

[deadastronaut]

hmmmm lm3914...no plate!...good range...check this out..looks good..

[Hides-His-Eyes]

that's pretty impressive.

[~arph]

Did whoever drew this build it with a 4093 and compare to the original ?

Yes, I did compare it with an original. It's just as hard to set up as the original, the setting of the trimpots is very delicate.

I like the earth and space interface here a lot more. It's much simpler to setup and uses lesser components and has a smaller footprint.

[The Tone God]

hmmmm lm3914...no plate!...good range...check this out..looks good..

I keep seeing people posting videos with different circuits but I point out that almost all of these vids are using skin contact and under controlled environmental conditions to make the circuits look good. Try that with a shoe on the floor at a humid outdoor gig and everything will function poorly.

Yes, I did compare it with an original. It's just as hard to set up as the original, the setting of the trimpots is very delicate.

I like the earth and space interface here a lot more. It's much simpler to setup and uses lesser components and has a smaller footprint.

Do you still have the circuit ? Is the IC socketed so you can swap them out to try a few different ones ? I really think there might be some better choices.

That being said I still think the circuit is a bad design. Alot depends on getting that 3906 working right. There are better designs that could be used for our needs. Mine uses about a dozen parts all easily found, most people probably already have them on hand.

Andrew

[tss]

hmmmm lm3914...no plate!...good range...check this out..looks good..

I keep seeing people posting videos with different circuits but I point out that almost all of these vids are using skin contact and under controlled environmental conditions to make the circuits look good. Try that with a shoe on the floor at a humid outdoor gig and everything will function poorly.

Yes, I did compare it with an original. It's just as hard to set up as the original, the setting of the trimpots is very delicate.

I like the earth and space interface here a lot more. It's much simpler to setup and uses lesser components and has a smaller footprint.

Can you please post the circuit? I am not getting anything from the so-called zvex circuit. I actually ordered a PCB for it and have about 5cm x 5cm plate to sense my hand but it does not work so I tried building it on a bread board and it did not work either. I really can't understand how someone could get this circuit working and in all situation on top of that...?

Do you still have the circuit ? Is the IC socketed so you can swap them out to try a few different ones ? I really think there might be some better choices.

That being said I still think the circuit is a bad design. Alot depends on getting that 3906 working right. There are better designs that could be used for our needs. Mine uses about a dozen parts all easily found, most people probably already have them on hand.

Andrew

[~arph]

Yes I still have an original wah probe here. I can swap IC's no problem (I'm not sure if it's socketed though..)

a 5x5 cm antenna is way too small, you need about 10 x 10 cm. Then you can try to get it working. what should work though is touching the plate. If while touching the plate you can't get the led to light up, something is wired wrong.

[Paul Marossy]

I keep seeing people posting videos with different circuits but I point out that almost all of these vids are using skin contact and under controlled environmental conditions to make the circuits look good. Try that with a shoe on the floor at a humid outdoor gig and everything will function poorly.

Yeah, things in the laboratory are usually different than in the real world.

[deadastronaut]

this subject sent me back to an old project i was working on...and still floating around in my head....and got me thinking......so i tried it again today..

i came up with 'dark light'..led/ldr combo a while back....which is good , but now ive just improved on  it...this works in daylight now due to the adjustment of sensitivity...(yep i took it outside in bright sunshine)...

if i was going for proximity, i'd go for this instead!...some may laugh at such ideas..but its dead simple and it works!..(keep it simple stupid)...no plate etc...

the led gets brighter the darker the ldr becomes..bread it..its tiny... like my brain...

10k pot!...to adjust sensitivity for different light conditions.....the only problem is when its dark though!... which could be overcome by having a right angled led facing the ldr...a few inches back...hmmm.....




just an idea!...

right now shoot!...

[artifus]

has anyone played about with linear hall effect sensors with a magnet in their shoe in this regard?

*edit* nice one d a. what value q1?

[deadastronaut]

has anyone played about with linear hall effect sensors with a magnet in their shoe in this regard?

*edit* nice one d a. what value q1?

npn 2n3904....works like a charm!.. its not fussy...

edit: try a 1M POT...better in daylight/dark..