Voodoo Main Discussion

[nixie]

Ok, I know the difference between the two typologies of mos, but I also thought that there were also some noise differences between the two circuits! i didn't think I would depend only from the mos type. Great, thank you.

[nixie]

Take the Voodoo schematic, label the battery-negative as ground, then re-label all the other voltage domains accordingly. See if that makes more sense.

Thank you Carl it's not that I don't understand the schematic but just simple curiosity! I remember seeing on some circuits a capacitor that separated the mosfet circuit from the preamp: this allows the use of a N-Mos and a traditional analogic mass with the -VB, but I'm not sure if this is an effective answer...

[MartinB]

Have not yet gotten that far. So far got it working and Disc ferrous/ nonferrous.
The Hybrid display starts indicating with a US one cent at about 10cm. Don't have audio output connected.
This is not a great distance but I still need to tweak timing, etc.

Hi waltr
I need to get back to Voodoo. I was getting similar results last time I worked on it. I have been working on Arduino PI for a while and the great thing is that it highlighted how much interference there is in my workshop. Too much metal for a coil to perform correctly. Now the sun is here I am working outside and making progress.

[Qiaozhi]

Arduino Nano Adapter Board For Voodoo

As promised ...

An adapter board that allows an Arduino Nano to be fitted in place of the original PIC18F4520 has been created.
There is a short description in PDF format attached below, along with the DipTrace files, Gerber and NC/Drill, and the Arduino sketch.

Enjoy!

Errata:
1. There is a typo in the PDF document on page 4. It should say "A jumper wire needs to be soldered between TP2 and TP18" ... not TP21.
2. It's C8 that needs to be moved to the underside of the PCB, not C22.

[6666]

Thanks George, are there any more pictures of the adaptor pcb in and out of the main pcb ?, just trying to work out the mounting.

[nixie]

Fantastic! Thanks George.
Just one question: since you went through the trouble to port it to arduino why then not use a stm32c103t8 (bluepill or blackpill)? You can use the same ide, the code is compatible, it has a lot of libraries and while some are specific to it they can be found easily. Also, its quite cheap at around 3 euros (https://www.ebay.it/itm/173558731928...8AAOSw4gxbPdxN) and its noticeably more performing than the pic, as a base it works on 3,3V but many pins are compatible with 5V. The biggest problem would be adapting the adc compartments which are 3,3V and 12bit, but then you would have plenty of gates and you can program it with a 2 euro stlink...
George, if there is a chance you wanted to redesign it ex-novo based on a stm32f103c8 I could give you a hand with the software and run the relative tests,... and for sure there are others who, like me, use arduino!!!

P.S.
I wanted to thank silverdog for their honesty and professionalism, everything arrived in perfect condition and on time.
Thank you very much.

[Qiaozhi]

Thanks George, are there any more pictures of the adaptor pcb in and out of the main pcb ?, just trying to work out the mounting.

You can see on the adapter board that there are two footprints that overlap each other. CONN1 is the connector for the PIC, and U1 is the Arduino Nano. You need to solder two 20-pin male headers to the bottom of the adapter to allow it plug in where the PIC usually goes, and two 15-pin female headers on the top of the adapter so that you can plug in the Nano. The 3D images below should show this more clearly.

[Qiaozhi]

Fantastic! Thanks George.
Just one question: since you went through the trouble to port it to arduino why then not use a stm32c103t8 (bluepill or blackpill)? You can use the same ide, the code is compatible, it has a lot of libraries and while some are specific to it they can be found easily. Also, its quite cheap at around 3 euros (https://www.ebay.it/itm/173558731928...8AAOSw4gxbPdxN) and its noticeably more performing than the pic, as a base it works on 3,3V but many pins are compatible with 5V. The biggest problem would be adapting the adc compartments which are 3,3V and 12bit, but then you would have plenty of gates and you can program it with a 2 euro stlink...
George, if there is a chance you wanted to redesign it ex-novo based on a stm32f103c8 I could give you a hand with the software and run the relative tests,... and for sure there are others who, like me, use arduino!!!

P.S.
I wanted to thank silverdog for their honesty and professionalism, everything arrived in perfect condition and on time.
Thank you very much.

Of course there are many many options available, and I cannot hope to satisfy all of them. Some people are liking the idea of a Raspberry Pi Pico, and others have asked about ESP32. I was just interested to see if an Arduino Nano could be used to drive Voodoo, and it appears that the answer is "yes", with some caveats.
Perhaps other members would like to explore different possibilities and create different adapters, or maybe even design a complete new PCB.

Personally I would like to move on to exploring something completely different. More later...

[surfdetector]

Personally I would like to move on to exploring something completely different. More later...

This sounds intriguing.........................

[nixie]

Personally I would like to move on to exploring something completely different. More later...

Yes! it's right!

[surfdetector]

As promised ...

An adapter board that allows an Arduino Nano to be fitted in place of the original PIC18F4520 has been created.
There is a short description in PDF format attached below, along with the DipTrace files, Gerber and NC/Drill, and the Arduino sketch.

Enjoy!

Errata:
1. There is a typo in the PDF document on page 4. It should say "A jumper wire needs to be soldered between TP2 and TP18" ... not TP21.

I believe there is a small typo within the pdf document where it states "Since C22 (22uF) causes a clash with the underside of the adapter board, it needs to be soldered on the bottom of theVoodoo PCB. R23 and R24 should also be installed before the adapter board is soldered in place."

That should be C8 which needs to be moved to the underside of the PCB

[6666]

You can see on the adapter board that there are two footprints that overlap each other. CONN1 is the connector for the PIC, and U1 is the Arduino Nano. You need to solder two 20-pin male headers to the bottom of the adapter to allow it plug in where the PIC usually goes, and two 15-pin female headers on the top of the adapter so that you can plug in the Nano. The 3D images below should show this more clearly.

Thanks the 3d pictures explains it ,

[Qiaozhi]

I believe there is a small typo within the pdf document where it states "Since C22 (22uF) causes a clash with the underside of the adapter board, it needs to be soldered on the bottom of theVoodoo PCB. R23 and R24 should also be installed before the adapter board is soldered in place."

That should be C8 which needs to be moved to the underside of the PCB

Damn ... you're correct.
That's what happens you write these things up late at night.
At least someone is paying attention.

[MartinB]

As promised ...

An adapter board that allows an Arduino Nano to be fitted in place of the original PIC18F4520 has been created.
There is a short description in PDF format attached below, along with the DipTrace files, Gerber and NC/Drill, and the Arduino sketch.

Enjoy!

Errata:
1. There is a typo in the PDF document on page 4. It should say "A jumper wire needs to be soldered between TP2 and TP18" ... not TP21.
2. It's C8 that needs to be moved to the underside of the PCB, not C22.

Thanks George.
Nice code.

[nixie]

I finally got almost all the components and I built the circuit (lacks mosfet tx and ic for filters),
first of all I wanted to test the voltages and the signals generated by the CPU:
these signals are the exact same as those described in the manual, voltage -5V ok but +5V is not present!!!
On tp9 the signal is perfect, on U8 the tensions on pin 8 = 0V (+VB), on pins 3 and 5 = -12V (-VB)
on pin 6 and 7 there is a signal very similar to SYNC but not perfectly square and amplitude around 8-9V starting from -12V
on pin 2 there is no oscillation.
I changed the 78l05 and 4 pieces of Lt1054 it does not change anything.
If I disconnect D6 and/or take off U7 nothing changes (no oscillation on pin2), same thing with a icl7660s.
Anybody can give me some advice?
George, can you post the image that's on pin 6 and 7 of U8?
thanks in advance

P.S.: powered by a 3-30V 10A desk power unit.