Moodz' Awesome Gold Pulse Induction Version 3 - MAGPI V3 Project

[moodz]

You have it almost totally right. The main reason that sensitivity is lost is because of overloading of the damping circuit ( eg avalanche or the damping control feedback voltage not tracking properly ).

I sort of know what to do but I dont have much time to to even tell you let alone test it.

Sorry about that.

[van0014]

Hello. I don't speak English. I received the chips and the metal detector is working. The firmware is 1.4. What do SIG, TSS, XSS, BAL, TSW, and XSW mean on the display? Four months ago, you said the firmware could be improved. Has anything changed?

Hello, I'll start by saying that the firmware I posted does not seem to be as sensitive as Moods' firmware. I mostly used artificial intelligence to make it.

I'll explain what I think the variables are. I cannot be certain.
SIG - Metal target signal. This changes as the magnetic field around the detector coil changes
TSS - Transmit signal start. This may be zero in the firmware. It might not actually be used
XSS - X sample start. This is the start point of when the reactive 'X' part of the signal is measured. It controls when the damping point happens, which should be about when the signal reaches zero. This must match the detector coil, and can vary per coil. It's critical for sensitivity and is best found with an oscilloscope, or by making sure your coil matches the recommended specifications
BAL - Balance. This should be the dividing point between two important signals. The receive signal time can be divided at this adjustable 'balance' point. The first part is used to sample the flyback error (by adjusting the balance, I think more or less of the signal is allowed in, but I don't quite know how it's used.). The second part, or the other side of the balance point, the latter half, is used for signal noise rejection.
TSW - Transmit signal width - The transmit pulse time, in microseconds or clock cycles, but probably in clock cycles. In the source code, a duty cycle of 3000 clock cycles can be resolved to mean a transmit time of 30uS. (3000 / 50 = 60uS). This corresponds to a 50% PWM signal happening in 60uS, or, 3000 clock cycles. At 50%, that's a 30uS Tx and a 30uS Rx. One of the most recent versions of the source code seems to have the time set to 5000, which is a 50uS transmit time. This may be a little bit too long, on my board, the MOSFET avalanches with anything above 42uS Tx on time.
XSW - X sample width. This directly affects the signal damping. It shortens or lengthens the amount of signal that is sampled, which then gives more or less weight to the damping signal.


The firmware I posted:
I better let people know that I no longer think the version I made is worth using. It is not as sensitive.

The bar graph is showing the balance. 750- and +750 shows the bar graph range, which is really mostly a gimmick. I haven't added anything. The balance is the same as before, but I offset it to zero. It's the number to the right of 1.60 (XSS) on the second LCD row.
The tone is at the top left, default 000. Volume is default 010. Then the signal is shown, and finally the voltage. It's a different layout but most or all information is there. The firmware has a different way of calculating the signal, which I believe uses an exponential increase to signal changes. The AI suggested a way of doing exponentials with some floating points between 0 and 1 to set the strength of the exponential increase. The code doesn't seem as sensitive after I changed a few things, and i'll need to put a bit more time in to get something that's not as experimenmtal

[IBGold]

I'm not sure what the reaction to gold is like. I had to tune my XSS. But I was also using modified firmware with too large of a Tx pulse. Now my detector seems to finally detect a large silver coin at 10cm. The last time I had gold, it couldn't detect it because my settings were wrong, and I was using modified source code. It was a tiny amount in a small container.

This is an updated version that includes a major change in audio and target response. Sine wave calculation sample array has been increased from 128 to 1024. MAGPI008_v1.4b.zip
Audio tone needs tweaking, but sounds better when increased.
ADC conversions now use interrupts instead of polling. Encoder turning needs tweaking

Auto ground balance tracking is included, as well as a different way of doing the exponential target response. Varying coil swing speeds are somewhat accounted for. The exponential rise gives reasonable responses for slow movements, and isn't quite as responsive on the faster movements. It's impressive how fast you can swing things past the coil and hear the response. The detector design is quite good. I like looking at the schematic and learning about it.

Hi Van0014,

I have responded to this post and sent you a PM.

Regards, Ian.

[haylaz0036]

Do you have a video of this project in action?Do you have a video of this project in action?

[AhmatAhmatov1959]

well I have an idea in the works .... it will improve things and you will be able to reuse the MAGPI circuit.
Might take a little while .... ( couple of months maybe or sooner if things work out ).

Hello. I don't speak English. I received the chips and the metal detector is working. The firmware is 1.4. What do SIG, TSS, XSS, BAL, TSW, and XSW mean on the display? Four months ago, you said the firmware could be improved. Has anything changed?

[IBGold]

I'm not sure what the reaction to gold is like. I had to tune my XSS. But I was also using modified firmware with too large of a Tx pulse. Now my detector seems to finally detect a large silver coin at 10cm. The last time I had gold, it couldn't detect it because my settings were wrong, and I was using modified source code. It was a tiny amount in a small container.

This is an updated version that includes a major change in audio and target response. Sine wave calculation sample array has been increased from 128 to 1024. MAGPI008_v1.4b.zip
Audio tone needs tweaking, but sounds better when increased.
ADC conversions now use interrupts instead of polling. Encoder turning needs tweaking

Auto ground balance tracking is included, as well as a different way of doing the exponential target response. Varying coil swing speeds are somewhat accounted for. The exponential rise gives reasonable responses for slow movements, and isn't quite as responsive on the faster movements. It's impressive how fast you can swing things past the coil and hear the response. The detector design is quite good. I like looking at the schematic and learning about it.

Hi Van0014,

I have not touched the Magpi for about 20 months due to illness but now you have an enabled version I re programmed it today it is one of Pauls so has all the correct components I am off to the specialist tomorrow so on Thursday I will have a play with it and report back if I can not work out the menu and how to drive it I will get back to you.

Regards, Ian.

[AhmatAhmatov1959]

I'm not sure what the reaction to gold is like. I had to tune my XSS. But I was also using modified firmware with too large of a Tx pulse. Now my detector seems to finally detect a large silver coin at 10cm. The last time I had gold, it couldn't detect it because my settings were wrong, and I was using modified source code. It was a tiny amount in a small container.

This is an updated version that includes a major change in audio and target response. Sine wave calculation sample array has been increased from 128 to 1024. MAGPI008_v1.4b.zip
Audio tone needs tweaking, but sounds better when increased.
ADC conversions now use interrupts instead of polling. Encoder turning needs tweaking

Auto ground balance tracking is included, as well as a different way of doing the exponential target response. Varying coil swing speeds are somewhat accounted for. The exponential rise gives reasonable responses for slow movements, and isn't quite as responsive on the faster movements. It's impressive how fast you can swing things past the coil and hear the response. The detector design is quite good. I like looking at the schematic and learning about it.

Hello. I was wondering if you've tested the metal detector in the field? Have you found anything? How did it perform?

[van0014]

Hello. Could you tell me what the reaction to gold is? I reflashed the 32-150 chip because it wasn't displaying the display, and I connected the coil without turning it off. The 9640 transistor immediately started smoking. I replaced all the components, but the circuit still didn't work. Instead of a TX pulse, I get a constant 2 V. I ordered the 32-250 chip; I'll test your firmware as soon as I receive it.

I'm not sure what the reaction to gold is like. I had to tune my XSS. But I was also using modified firmware with too large of a Tx pulse. Now my detector seems to finally detect a large silver coin at 10cm. The last time I had gold, it couldn't detect it because my settings were wrong, and I was using modified source code. It was a tiny amount in a small container.

This is an updated version that includes a major change in audio and target response. Sine wave calculation sample array has been increased from 128 to 1024. MAGPI008_v1.4b.zip
Audio tone needs tweaking, but sounds better when increased.
ADC conversions now use interrupts instead of polling. Encoder turning needs tweaking

Auto ground balance tracking is included, as well as a different way of doing the exponential target response. Varying coil swing speeds are somewhat accounted for. The exponential rise gives reasonable responses for slow movements, and isn't quite as responsive on the faster movements. It's impressive how fast you can swing things past the coil and hear the response. The detector design is quite good. I like looking at the schematic and learning about it.

[AhmatAhmatov1959]

I've spent a bit of time on the firmware source, and had really wanted to have a bar graph for showing the balance. And to have the encoder use interrupts. After spending many days using AI and tweaking the code, I've made something I like. Encoder doesn't feel fast, though I once had the code to a point where it did. It's not perfect, but attempts to show all useful variables while also adding a somewhat useful graph-like display.

It took me a bit of tweaking to get full sensitivity, or at least, better than before. The design is very sensitive, when build as intended. I used some slightly different parts in mine and it’s taken me a bit to work out

After spending much of my spare time trying to improve on this detector, and finally having it work nearly as good as it’s supposed to, I can appreciate something that was talked about in the book ITMD 3, where it said something like ‘shoot the engineer’, meaning it’s time to actually use it

Hello. Could you tell me what the reaction to gold is? I reflashed the 32-150 chip because it wasn't displaying the display, and I connected the coil without turning it off. The 9640 transistor immediately started smoking. I replaced all the components, but the circuit still didn't work. Instead of a TX pulse, I get a constant 2 V. I ordered the 32-250 chip; I'll test your firmware as soon as I receive it.

[van0014]

I've spent a bit of time on the firmware source, and had really wanted to have a bar graph for showing the balance. And to have the encoder use interrupts. After spending many days using AI and tweaking the code, I've made something I like. Encoder doesn't feel fast, though I once had the code to a point where it did. It's not perfect, but attempts to show all useful variables while also adding a somewhat useful graph-like display.

It took me a bit of tweaking to get full sensitivity, or at least, better than before. The design is very sensitive, when build as intended. I used some slightly different parts in mine and it’s taken me a bit to work out

After spending much of my spare time trying to improve on this detector, and finally having it work nearly as good as it’s supposed to, I can appreciate something that was talked about in the book ITMD 3, where it said something like ‘shoot the engineer’, meaning it’s time to actually use it

[AhmatAhmatov1959]

Извините. Ошибся. Использую версию MAGPI008.X.productionV1.2_MX150

Sorry, I made a mistake. I'm using the version MAGPI008.X.productionV1.2_MX150

[AhmatAhmatov1959]

MAGPI008_2023_01_28_MX150.zip

Извините. Ошибся. Использую версию MAGPI008.X.productionV1.2_MX150

[AhmatAhmatov1959]

which version of the firmware are you using

MAGPI008_2023_01_28_MX150.zip

[moodz]

which version of the firmware are you using

[AhmatAhmatov1959]

Please post some photos of the board top and bottom and we will try to assist.

Hello Moodz I have a PIK32MX150 chip installed. Does it work with the 2004 LCD? I connected 2 pieces and the screen lights up but they don't work.