Help tuning Invisible touch

[DWBH]

I've populated a Invisible Touch board from Zero the Zero's site (Topopiccione).

Now, the schem that's on his site is to use with a 20x12 cm board. I want to use a 12x9cm board. Now, tha problem is that components like C1, C2, C5 and also R4 have to be tweaked. I already installed a trimpot in R4's place, for easier maneuvering.

My question is, I've been around this for a few days now and I haven't found a perfect combo...
Zero the Zero told me that C1 and C2 would have to have smaller values when wanted a smaller antennae, since the frequency of both oscillators must be higher R4 is for fine tweaking and R5 is the main trimpot, that 'controls' C2.

Anyway, I'd like to ask you guys who have built this circuit what capacitor/resistor values did you use and also, what size was your antennae?

Any help would definitely help me.

[DWBH]

bump

[Ry]

I remember mine being very affected by what I was driving...some LEDs wouldn't turn on.  It's still on my breadboard, so I will check out what values of C1 and C2  I ended up using.  My antenna is a piece of single sided copper clad board about 6x3 inches or so.  I seem to recall that I had to use a multi turn pot to get it tuned in as well.

More details later in the day.

Ry

[DWBH]

Well, now, mine doesn't even turn on (the led). 

I don't know what happened. Might try swapping that transistor, as I think yesterday it was quite hot (either was the transistor or the elec cap).

Thanks Ry

[Ry]

Okay, C1 is 10pf and C2 is 47pf on mine.  I remember now that I did play around with different cap values a little bit before getting it to work.  My antenna is about 6" by 2" single sided copper clad board and my LED is a plain red one.  I used a multi turn 50k pot as a trimmer.  I think you'd have a difficult time tuning it in without a multi-turn trimmer, but I may be wrong.  It seemed like there was a very narrow range of the pot travel where the antenna worked correctly.

Ry

[DWBH]

What about the sensitivity of the antennae? How tall is the RF energy field?

[DWBH]

Well, I can tell you this: this shit is unstable.
Next time I build it, I might consider re-draw the pcb into something larger, 'cause my transistor sockets don't fit. 
Also, I have to buy a multiturn trimmer. Mine's singleturn.

[Ry]

Insert Quote
What about the sensitivity of the antennae? How tall is the RF energy field?

I had a couple inches of play around the antenna.  Don't give up, this is very cool to see work.  I would recommend building it on a breadboard, however, so that you can quickly swap out whatever size components you need.

[DWBH]

I have sockets for C1, C2 for the elec cap and also for R4 I guess.

I don't know, but sometimes it works quite well, then i suddenly touch the transistor or a cap and the led just stays on. Then I touch somewhere else and it turns back to normal.

I haven't measured the height of the RF energy bubble but it seems to me that is rather small.

Only Ry out there?? 

[DWBH]

Another bump just to say that I played with it again this evening (well, just know actually). I substituted TR1 for a 100k pot, and I think this method is much better. It's easier to 'tune' and you can have lots of 'sensitivities', if you know what I mean. Also, I remember RG saying that the circuit is very thermal-sensible. So, once again, it's easier to tune with a actual full-size pot (and not those mini-screwdriver-little-bastards  ).

Also, I found something rather interesting while playing with this thingy. When I pick the pcb up and I grab it with two fingers (not touching the copper tracks), the finger that is closer to IC3 determines the reaction of the sensor. For intance, when my finger was near IC3, the sensor responded normally (today I managed to get sth like 3cm of RF energy!!). However, when the board was on some surface, the sensor reacted differently, like abnormally. Static electricity/human electricity, perhaps?
I might try and experiment some other values for the electrolytic cap... Sometimes, just a touch on a cap or a transistor/chip puts the led on all the time!... then normally I have to wait for 30 seconds, and it turns back to normal....

Well, it's a heck of a circuit. It's funny and funny also.

[DWBH]

Just hopped in to say: I have like 3cm of RF energy. It's not that high actually, but I think I can get to 5cm or so....

I'm thinking of putting a pot instead of R4, also.... Where's Zero the Zero???

[DWBH]

Wrong forum, sorry.