Voodoo Main Discussion

[Qiaozhi]

So we need to change wording on page 29 and add to post #1, good to see these things being found.

It's very difficult to get technical documentation 100% correct. I was reading an Arduino book recently, and discovered several errors. The book was published by a reputable publishing company, and their experienced proof readers still managed to miss stuff.

[Math]

Hi George, the iron chatter you mention a couple of times in the book may be mostly eliminated using a '3rd channel' in software as "Disc minus Phase" here this should be Disc - PI channel then triple AND the 3 channels for the final output..
Ive used it successfully on a couple of projects it works well for the mismatched channel overlaps at crossovers.. usually big iron!

Hang on theres another bit of logic to go with that 3rd channel.. let me just check back..

[lamoiz]

Hi everyone . I was away yesterday, I had a car accident problem .... a girl and her cell phone smashed my car at a crossroads ... put my car in the trash .. *****.
Otherwise here are some pictures of the oscilo ..
tp3 tp2
tp5 tp2tp6 tp3
tp9 tp2
tp10 tp3

a lot of noise on tp3 ..pff I don't know why ..

[Math]

Ok its when both channels go high.. then
before sending audio output start timing the signal..
If its short duration and either channel are higher than
a small signal level then ch.3 'Disc minus Phase' must be high
If so then send detector audio output..

Here 'ch3' may be 'PI minus disc' as its the disc channel that has the phase element

Hi Lamoiz i hope youre OK.. im starting Voodoo construction tonight
ill see what i get on tp3..

[lamoiz]

thank you Math, it's okay ..
George, I still have the beeps beeps beeps all the time .. do you have any idea where this could be?

[surfdetector]

I am complete on the Bench

I have completed my build on the bench. I need to wait for some parts and then I shall box up the project and take it out for a spin. I shall post a short video tomorrow on my YouTube channel of the project operating in Hybrid mode. I have attached a picture from the Disc pre-amp output which appears somewhat different than in the book. I am getting about 8" on a George VI penny and about 5" on a US nickle. More tweaking is needed, currently I have all settings in default and I am using a F75 coil.

[lamoiz]

I have completed my build on the bench. I need to wait for some parts and then I shall box up the project and take it out for a spin. I shall post a short video tomorrow on my YouTube channel of the project operating in Hybrid mode. I have attached a picture from the Disc pre-amp output which appears somewhat different than in the book. I am getting about 8" on a George VI penny and about 5" on a US nickle. More tweaking is needed, currently I have all settings in default and I am using a F75 coil.

[ATTACH]53849[/ATTACH]

hi surf,
me too I finished a long time ago, but I still have the beeps .. and I can not find the problem .. me the test was done with the tesoro .. and my other home coil works too.

[surfdetector]

hi surf,
me too I finished a long time ago, but I still have the beeps .. and I can not find the problem .. me the test was done with the tesoro .. and my other home coil works too.

Hi,
Do you get the beeps in both hybrid and PI mode? I wonder if you are getting EMI that could be causing it?

[lamoiz]

Hi,
Do you get the beeps in both hybrid and PI mode? I wonder if you are getting EMI that could be causing it?

I have the beeps in pulse mode, very little in hybrid mode.
I tried outside, it's the same problem, I don't understand,
what do you think of the tp3 measure? there is a lot of osciliation after the impultion .. no ??

[sbalio1]

hi friends i have pic18f452 can i use it for this machine

[surfdetector]

I have the beeps in pulse mode, very little in hybrid mode.
I tried outside, it's the same problem, I don't understand,
what do you think of the tp3 measure? there is a lot of osciliation after the impultion .. no ??

What does your coil flyback look like?

[Qiaozhi]

Hi everyone . I was away yesterday, I had a car accident problem .... a girl and her cell phone smashed my car at a crossroads ... put my car in the trash .. *****.
Otherwise here are some pictures of the oscilo ..
[ATTACH]53841[/ATTACH]tp3 tp2
[ATTACH]53842[/ATTACH]tp5 tp2[ATTACH]53843[/ATTACH]tp6 tp3
[ATTACH]53844[/ATTACH]tp9 tp2
[ATTACH]53845[/ATTACH]tp10 tp3

a lot of noise on tp3 ..pff I don't know why ..

Sorry to hear about the car accident. Hopefully no-one was injured.

Firstly - switch your scope channels from AC coupling to DC.
Secondly - do you have your scope probes set to x10? The amplitudes of the signals are both about 10 times smaller than expected.

Please change the settings and re-post the images.

[Qiaozhi]

Hi George, the iron chatter you mention a couple of times in the book may be mostly eliminated using a '3rd channel' in software as "Disc minus Phase" here this should be Disc - PI channel then triple AND the 3 channels for the final output..
Ive used it successfully on a couple of projects it works well for the mismatched channel overlaps at crossovers.. usually big iron!

Hang on theres another bit of logic to go with that 3rd channel.. let me just check back..

When I was discussing chatter in the book, I was referring to some of the experimental prototype versions. At one point (page 10) I state: "Eventually after much effort, the noise, instability, chatter, and timing issues were all resolved."

[Qiaozhi]

I have completed my build on the bench. I need to wait for some parts and then I shall box up the project and take it out for a spin. I shall post a short video tomorrow on my YouTube channel of the project operating in Hybrid mode. I have attached a picture from the Disc pre-amp output which appears somewhat different than in the book. I am getting about 8" on a George VI penny and about 5" on a US nickle. More tweaking is needed, currently I have all settings in default and I am using a F75 coil.

[ATTACH]53849[/ATTACH]

Well done. That looks good.
The extra ringing is occurring during the TX-on time, and does not affect correct operation of the detector. Fig. 2-1 shows the result for a Troy coil, so the Fisher F75 coil may quite possibly be different.

[Qiaozhi]

hi friends i have pic18f452 can i use it for this machine

Not without modifying the source code to handle the differences and then re-compiling to generate a new hex file.
http://ww1.microchip.com/downloads/e...doc/39647a.pdf