Problems with fresh built TGSL

[qute1]

looks acceptable coil chu does it sing though some plastic coated and teflon coated sing in circuit its not a bad thing as you can at least hear the circuit is feeding the coil!

[chuubaba]

these coils are working but the circuit does not detect a euro size coin even if i place it on coils but it can detect a 4"x4" copper clad board few centimeters away

looks acceptable coil chu does it sing though some plastic coated and teflon coated sing in circuit its not a bad thing as you can at least hear the circuit is feeding the coil!

[qute1]

tgsl is vhf ? if it was pi i would say that delay was off but?

[dbanner]

This is the reason for the device not working. You used wrong wire. You are supposed to use enameled copper wire. Your inductances of the coil are different from what you require. However you can remedy this. Do you have inductance meter or frequency meter?
You must measure the inductances of the coils you made. You can do this if you at least have meter which can measure frequency.
Put meter to the two wires of the TX coil while circuit is on, and measure frequency.

[chuubaba]

i have multimeters and analog oscilloscope only

http://www.diyspacepk.com/product/di...er-dt-830-dmm/

http://emin.vn/en/Analog-Oscilloscop...7p3797sl2.html

This is the reason for the device not working. You used wrong wire. Your inductances of the coil are different from what you require. However you can remedy this. Do you have inductance meter or frequency meter?

[Andi68]

https://www.ebay.com/sch/i.html?_nkw=lcr-t4+tester

[chuubaba]

I also have this multimeter and it is having a signal generator function. Can this assist the scope?

[dbanner]

No.
Download and install this:
https://www.zeitnitz.eu/scope_en
This software has frequency counter to measure frequency as digital display.
Then make an interface circuit that plugs into soundcard.
Then you can measure exactly the frequency of TX. From this you can work out inductance of coil using resonance calculator which you can also download and install on computer.
You can find simple probe circuit online consisting of couple resistor and diode. Make this which will plug into soundcard.
After measuring TX coil, then removed and hookup Rx coil to tx circuitry. Now measure the frequency likewise. Use resonance calculator to work out inductance. Now you will know inductances of both coils.
Knowing this, you can work out changes to caps values for tuning your coil. In

[kt315]

he have nice analog 2 channel 20mHz oscilloscope. thats enough even for a PI.

[dbanner]

he have nice analog 2 channel 20mHz oscilloscope. thats enough even for a PI.

How to measure inductance on oscilloscope? For Chu it will be like finding penguin in North Pole.Sorry Chu. I just offer easiest way.
His coil has wrong inductances because I said before, he used plastic insulated wire!
The software I recommend has frequency meter and can measure frequency.
He just needs to tune his coils to correct resonances.
Later on, he can make other coils if he wants and purchase cheap lcr meter but for now, at least he will be able to work out the inductances.

[chuubaba]

Dbanner i highly appreciate your suggestion but i sounds like far above my level of experience but i will certainly give it a try. In the meanwhile I think i will ask a local electronic repair shop if they can measure the inductance for me. I will let you know the inductance and then we will look for a suitable capacitor to mend the coil.
There is one more thing. I winded both my Tx and Rx coils clockwise. Is this ok?

No.
Download and install this:
https://www.zeitnitz.eu/scope_en
This software has frequency counter to measure frequency as digital display.
Then make an interface circuit that plugs into soundcard.
Then you can measure exactly the frequency of TX. From this you can work out inductance of coil using resonance calculator which you can also download and install on computer.
You can find simple probe circuit online consisting of couple resistor and diode. Make this which will plug into soundcard.
After measuring TX coil, then removed and hookup Rx coil to tx circuitry. Now measure the frequency likewise. Use resonance calculator to work out inductance. Now you will know inductances of both coils.
Knowing this, you can work out changes to caps values for tuning your coil. In

[kt315]

How to measure inductance on oscilloscope?
---
very easely. take generator LC if you know the frequency and C value you can calculate L according resonance formula.

[chuubaba]

I can try to measure inductance on oscilloscope but it requires a generator that i don't have. Is there a method to discover inductance with use of my oscilloscope only?

How to measure inductance on oscilloscope? For Chu it will be like finding penguin in North Pole.Sorry Chu. I just offer easiest way.
His coil has wrong inductances because I said before, he used plastic insulated wire!
The software I recommend has frequency meter and can measure frequency.
He just needs to tune his coils to correct resonances.
Later on, he cay make other coils if he wants, but at least he will be able to work out the inductances.

[dbanner]

You don't need an LC generator, you have your TX oscillator! It is part of your detector circuit! It is an oscillator(LC generator), the coil and cap make up the LC.
My God. KT is reverse trolling. Haha.

[kt315]

trolling? me? who released GOLD MOUNTAIN TECH KING COBRA? i know this gen of every detail!