Voodoo Main Discussion

[ivconic]

Only three mistake is a very good result!
Now it can only goes well!


Regarding Voodoo, I agree with you about to avoid the binary audio.
PWM could be an option but also a simple R-2R DAC network could do the job.

Yes that would be even simpler solution, with engaging several spare pins.
I am just looking at schematics and i see RA2, RA3 and RA5 are unused.
Quite enough!

[Altair]

Only three mistake is a very good result!
Now it can only goes well!


Regarding Voodoo, I agree with you about to avoid the binary audio.
PWM could be an option but also a simple R-2R DAC network could do the job.

[ivconic]

Small notice:
1) In case of 9v battery; U30=7660 and D6=7V5, (U30 can be 1054 too)
2) In case of 12v battery; U30=1054 and D6=9V1.
...
So far i made many Barracuda's and all supplied with 9V, so 7660 is working there pretty cool and correct.
Lately i made Voodoo, supplied with 12v, for testing purposes i put 7660 and it gets hot within seconds.
Probably would die if left longer. So 1054 is must if supply is 12v and over.
I left options in schematic and pcb for 9V and 12V supplies.
7660 is peanut price while 1054 is pretty hot!
Since this is only small testing circuit; i don't see much of a sense to waste money before is tested and proven good.
So i plan to use 7660 and supply it with 9V. If i like it; later on to use 1054 and supply it with 12V.
...
Voodoo is the main aim here. I will use DBowers idea, make it, test it and see what will come out of it.
But all this in service of making final success with Voodoo.
Changes in code are mandatory. Mostly related to audio behavior.
Non motion binary audio is first subject to change.
Logically: small changes on circuit are needed too.
Instead of simple "pulling" (switching) the audio; VCO controlled by PIC is desirable.
RA4 should provide PWM output "mapped" to signal amplitude... for example.

[ivconic]

... but I will suggest to take in consideration the variant showed at post #942...

Done;

[ivconic]

Well made Ivconic!
I have checked your work and found these points to fix on PCB:
1. Q1 is marked as 327; it should be 64
2. Q1 has emitter and collector inverted
3. R34 is missing
4. C14 value must be 1nF
5. Connection between R24 and R27 is missing but I will suggest to take in consideration the variant showed at post #942
6. Capacitor value between pin 5 of U1 and 0V is missing; it's should be 10n (on schematic this capacitor is missing)

Test points are missing on schematic.

The rest seem OK!

Bravo! Good eyes!
Explanation:
1. I put BC327 because is easier for me to obtain BC327/40 than MPSA.
2. BC327 pinout is CBE while MPSA is EBC.
(MPSA is darlington, BC327 is not. But it will do the job just fine there.)
3. Correct! I take this as first mistake.
4. Correct! This is second mistake.
5. Correct! Third one.
6. I asked about it at the time i drawn schematic, since it is missing from the previously posted schematic. I got no answer. Yet i "reserved" a space for it on pcb.
...
3 mistakes on pcb... not bad at all for me lately! Since i am completely out of focus. It is quite "normal" for me lately to make several mistakes while drawing pcb.
Later on in process of soldering and testing; usually i locate the mistakes.
But it is better to start without them at all.
I will try to correct those on existing draw and post final correct one.
Thanks!

P.S.
In meantime corrected:

[Altair]

This need to be checked by "neutral eyes":

Well made Ivconic!
I have checked your work and found these points to fix on PCB:
1. Q1 is marked as 327; it should be 64
2. Q1 has emitter and collector inverted
3. R34 is missing
4. C14 value must be 1nF
5. Connection between R24 and R27 is missing but I will suggest to take in consideration the variant showed at post #942
6. Capacitor value between pin 5 of U1 and 0V is missing; it's should be 10n (on schematic this capacitor is missing)

Test points are missing on schematic.

The rest seem OK!

[6666]

I can sample immediately after the main clock and is adjustable out to 40uS with the current delay resistor. Sample width is 10uS

Thanks for doing that Don, its very helpfull, cheers

[dfbowers]

I will check it out when I get a chance. It’s totally dependent on the resonant frequency of the RX coil. It will work over a wide range of frequencies as long as you can adjust your delay to cover the first cycle of the decaying sine wave. Also, the sample width needs to sample shorter than 90 degrees. If you check my previous post you can get an idea. I will take some measurements and post them up shortly..

I can sample immediately after the main clock and is adjustable out to 40uS with the current delay resistor. Sample width is 10uS

[SilverSurfer17]

I plan on using this on my etrike and want the etrike to run on 72 volts but be able to use 12 for the detector off the same battery pack

[SilverSurfer17]

I think more people need to pay attention ive seen year old Harleys burn to a crisp from reversing charging cables and boosting it and i can see someone building a 18650 and doing that

[ivconic]

Of course that's nice way to make protection.
But there are cases when you use high capacity batteries that usually provides higher nominal voltage than the working voltage in the device.
If you don't mind the voltage drop across the diodes; this circuit is the simplest but very effective possible protection against reversing the polarity.
I am using it at low consumption circuits (most of the I/B detectors) and when battery is with higher capacity.
Common detectorist in time becomes unsatisfied with frequent change of batteries and eventually one day decide to use "external" rechargeable accu with high capacity.
And that's where "tragedy" happens! After some time of use like that; it happens to reverse the cables that goes to battery and result is: lot of magic smoke around and dead detector.
I was pretty tired of such cases, some people will never learn, so after few repairs of the same damage: i started to use this protection.
SMW for example will run smoothly with 9v. Accu is usually 12V/1Ah. (charged 13.6v). So voltage drop across the bridge is not a problem.
You may call it stupid; but is saves the day. Users are satisfied and i am not annoyed to death by servicing same faults all over again...

[surfdetector]

Randomly i stumbled across this nice girl explaining the options:

Very interesting video. Thanks

[ivconic]

Hi Ivconic , good work, I have had a look at the diode I requested but it appears to be drawn in parallel which requires a fuse to be placed in power lead which is ok it will work, but people seem to get it wrong and dont add the fuse

but what I was asking for was a series diode something like a 1N5822 40v 3A Schottky, if people dont want it they can short it out, what are your thoughts ?

Randomly i stumbled across this nice girl explaining the options:

[Altair]

About DISC integrator, this is what I would intend to try:

[dfbowers]

Hello Don, would you know approx how many micro seconds after the TX pulse that your 4066 operates to take your Disc sample ?. thanks

I will check it out when I get a chance. It’s totally dependent on the resonant frequency of the RX coil. It will work over a wide range of frequencies as long as you can adjust your delay to cover the first cycle of the decaying sine wave. Also, the sample width needs to sample shorter than 90 degrees. If you check my previous post you can get an idea. I will take some measurements and post them up shortly..