Quote:
Originally Posted by Qiaozhi
Goldmaxx - Today I made some tests with the TOTeM prototype unit. It appears to work better if the power supply is between 8 to 9V. If the battery is greater than 9V (e.g. 9.5V), the increased voltage can cause an offset in the meter, so that it is not located at zero when there is no signal. However, if you ignore the meter offset, then everything else works as expected. It might be worth using an 8-cell battery pack with an 8V or 9V regulator to power the circuit.
I also removed the hot glue around the ferrite coil, and played around with the coil balance. The null is extremely easy to find, although it can be tricky to find the position where ferrous (iron) targets are rejected. At one balance position I was able to detect a Victorian penny at 5 inches from the TX coil, while rejecting iron.
If there is an external signal being received, such as from a laptop computer, then this will cause a beep even if TOTeM is pointing away from the source. So this is an easy way of deciding whether the signal is external interference or not.
As described in Chapter 14 of ITMD, the compass and sky effects seem to be related to the use an unshielded RX coil, and the sky effect can be experienced by using either a standard Heathkit GD348 or a Micronta 4001. There is no compass or sky effect with TOTeM, since it uses the ferrite coil as a receiver in active mode.
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Hello Qiaozhi
this is very excellent and truly very good news. Your TOTeM reacts exactly like mine.
The best results I had with the old 9V battery with 8.22V.
With this power I was able to locate gold and silver ring from the TX coil in the active mode.
When the voltage was higher, the TOTeM has nothing detected before the coil.
With the old battery, I have calibrated the coils. That was really easy, I have it calibrated by the yellow LED and so long the RX coil displaced until the yellow LED is no longer became darker.
So you can calibrate the coils precise than with the sound.
Incidentally, I have calibrated my totem in a dark room, because so you can see better the light of the yellow LED. This was also the position where I could not detect any iron.
Wow, I must say that to detect Victorian penny in a 5 inches distance, is a very good performance and even better than my totem.
But I probably did not have the correct voltage, because I only had the old battery and the voltage was determined to be low.
But I can very well imagine that the 5 inches are realistic.
And Qiaozhi, I do not know if you've tried it. The TOTeM detected not only gold and silver from the TX coil, it can detect bronze too.
I tested it with a Roman As and he shows me it perfectly, but it does not respond to iron.
This is really brilliant because there are very beautiful Celtic artifacts of bronze and it would be great if the totem could also be detected it.
I will soon make a little video and post it here.
I can very well imagine that the TOTeM perhaps with 9V is too sensitive and that maybe the solution for my North - South line problem is.
Although I must say that the totem with 9V the spark test, can be detected over a greater distance. But it does not if it indicate other frequencies too.
Okay, I'll try next step to get a 9V regulator PCB and integrate them.
Qiaozhi, maybe you have, or someone from the forum a good PCB circuit for a 9V regulator?
Best with 12V input and a potentiometer for regulating the voltage on the PCB.
Thus, one could better experiment with the power in order to achieve the best result.
Qiaozhi So let us build a super LRL.
best regards