Voodoo Main Discussion

[waltr]

I also had this problem. You need to search this thread for my solution detail. Best memory is that I added a resistor from the 1054 input to output to 'kick start' it.

[Qiaozhi]

Good evening, I wanted to ask the gurus of the Forum, after having assembled the circuit of the Voodoo Project, I found the problem highlighted by Mr. Nixie post 1477, where he had reported that he did not have +5 volts on pin 15, and after removing the 20k r48 resistor, +5 volts magically appeared. From your suggestions he had been told to replace the LT1054, perhaps it was a remarked 7660. I have tried three LT1054s bought from different suppliers, but nothing. Please help me solve this question.
Thanks again for your patience.

Check the free-running frequency with a scope. If it's 10kHz then it's a 7660. The LT1054 has an internal clock of 25kHz.

[dgm]

I wanted to ask the members of this Forum who have ventured into the construction of this futuristic Metal Detector, professionally designed by Mr. George, to carry on and publish the results of their very interesting progress. Thank you Mr. George for your time on this project !!

[Carl-NC]

I have moved this thread to a dedicated Voodoo forum. I encourage people to open new threads for particular discussions so it becomes easier for others to find relevant information. If you have posts in this thread you would like extracted to a separate thread let me know.

[dgm]

Good evening, I have some problems with the voodoo project, I tried and tried again all the advice I got from the gurus of this Forum, but I haven't solved it yet. the problem of power supply +5 missing to the Tp 15, the 20k R48 if it is disconnected you have +5 volts, instead if it is connected 0.85 volts. I replaced several LT1054s purchased from different vendors, but nothing. with the R48 unplugged the circuit seems to work in both Pi and hybrid, but I have noticed that the audio is very low, and the U6 79l05 heats up a bit and the 78l05 remains cold. I don't know where to look for the problem. Thanks for your kind help.

[Qiaozhi]

Good evening, I have some problems with the voodoo project, I tried and tried again all the advice I got from the gurus of this Forum, but I haven't solved it yet. the problem of power supply +5 missing to the Tp 15, the 20k R48 if it is disconnected you have +5 volts, instead if it is connected 0.85 volts. I replaced several LT1054s purchased from different vendors, but nothing. with the R48 unplugged the circuit seems to work in both Pi and hybrid, but I have noticed that the audio is very low, and the U6 79l05 heats up a bit and the 78l05 remains cold. I don't know where to look for the problem. Thanks for your kind help.

Did you see my post in #1517?
What is the free-running frequency of your LT1054?

Do you have a sync pulse on TP9?

[dgm]

Yes I read your post thanks for replying, I wanted to tell you that my experience in electronics is a bit rusty, with my oscilloscope I tried but I didn't succeed in it. I have built several metal detectors, but I liked the one you designed a lot. Thank you Mr. George for your patience.
Yes I have a programming impulse on the TP 9!

[Carl-NC]

If you have a pulse on TP9 then probe the collector of Q5. It should be an inverted version of the same waveform. Then probe the collector of Q6 (with R48 installed), it should be the same waveform as TP9. Recheck Q5 & Q6, make absolutely sure they PNP & NPN, and make sure of the pinout. Some transistors are EBC, some CEB. It's likely you have a wrong transistor, wrong pinout, or blown transistor.

[dgm]

Thank you very much Mr. Carl, I'll do the checks right away. I will write the results as soon as possible.

[yatahaze323]

Hi George, was there any reason why you used the oled display on the nano version vs. the lcd display in the original version?

[Qiaozhi]

Hi George, was there any reason why you used the oled display on the nano version vs. the lcd display in the original version?

If you look at the DipTrace schematic for the Arduino Voodoo adapter you will see that the connections are already there on D6 to D11 for the LCD.
I just wanted to use an OLED as an alternative. You can easily change the code to use the LCD if you desire. In fact the LCD is arguably easier to drive than the OLED, and may even be faster since it uses a 4-bit parallel connection instead of SPI.

[dgm]

Hi Mr. Carl and Mr. George good evening, as promised I carried out your suggestions, without the R48 I tested the TP9 as per file n.1, then I tested the collector of transistor Q5 as per file n.2, last I inserted the R48 and tested the manifold of the Q6 as per file n.3. I changed the 79l05 - 78l05 - Q5 and Q6, but the result does not change, on the TP 14 I read -5, and on the TP15 +0.85. The 79l05 heats up and the 78l05 no. I don't know where to look. Thank you for your patience.

[Qiaozhi]

Hi Mr. Carl and Mr. George good evening, as promised I carried out your suggestions, without the R48 I tested the TP9 as per file n.1, then I tested the collector of transistor Q5 as per file n.2, last I inserted the R48 and tested the manifold of the Q6 as per file n.3. I changed the 79l05 - 78l05 - Q5 and Q6, but the result does not change, on the TP 14 I read -5, and on the TP15 +0.85. The 79l05 heats up and the 78l05 no. I don't know where to look. Thank you for your patience.[ATTACH]55862[/ATTACH][ATTACH]55863[/ATTACH][ATTACH]55864[/ATTACH]

If you remove the 78L05, what voltage is present on the cathode of D6?

[dgm]

On the cathode D6 11,7 volt.

[Qiaozhi]

In that case the LT105 appears to be working. There must be something loading the 78L05.