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Several years ago I developed a modular metal detector platform whereby individual subcircuits are broken out into plug-in modules. Here is the motherboard:
The modules are Preamp, Demod, post-demod Filter, ADC, and Micro. The micro was an STM32F767 Nucleo (Cortex M7), the ADC was the ADS131E08 (24-bit 8-ch simultaneous sampling).
I had built maybe 30 modules for this but all of this was on my moving truck that was stolen 2 years ago. All I have left is this blank motherboard.
I had already identified some deficiencies in the design so I redesigned everything last year. Here is the new motherboard:
I eliminated the ADC and Nucleo making this an all-analog motherboard. I may eventually design a digital motherboard to mate with this.
There is a Power module (AVCC) that supplies +/- V to all the modules.
There is a TX module that can support a basic VLF, PI, or multifrequency transmitter. Bigger, more complex TX circuits will have to use a separate board.
There are 2 Preamp modules that can have dedicated RX coils or can share a single RX coil (jumper selected).
There are 4 Demod modules, each one is a quadrature demod. This means you can run a 4-frequency MF design, or do an 8-sample PI design. Each demod can accept inputs from either Preamp (jumper selected).
There are 4 Filter modules, each follows one of the demods.
Every module has a clock header.
A final header contains the 4 (X,R) signal pairs for exporting to an ADC.
The real purpose of this (for me) is to build parallel channels and compare, ferinstance, different demod topologies.
Here is the new motherboard with some unfinished modules:
Most of the components are SMT except where I want to easily swap opamps or caps. It's obviously not meant for high-performance or for outdoor portability but it's a lot better than an ACE breadboard.
The modules are Preamp, Demod, post-demod Filter, ADC, and Micro. The micro was an STM32F767 Nucleo (Cortex M7), the ADC was the ADS131E08 (24-bit 8-ch simultaneous sampling).
I had built maybe 30 modules for this but all of this was on my moving truck that was stolen 2 years ago. All I have left is this blank motherboard.
I had already identified some deficiencies in the design so I redesigned everything last year. Here is the new motherboard:
I eliminated the ADC and Nucleo making this an all-analog motherboard. I may eventually design a digital motherboard to mate with this.
There is a Power module (AVCC) that supplies +/- V to all the modules.
There is a TX module that can support a basic VLF, PI, or multifrequency transmitter. Bigger, more complex TX circuits will have to use a separate board.
There are 2 Preamp modules that can have dedicated RX coils or can share a single RX coil (jumper selected).
There are 4 Demod modules, each one is a quadrature demod. This means you can run a 4-frequency MF design, or do an 8-sample PI design. Each demod can accept inputs from either Preamp (jumper selected).
There are 4 Filter modules, each follows one of the demods.
Every module has a clock header.
A final header contains the 4 (X,R) signal pairs for exporting to an ADC.
The real purpose of this (for me) is to build parallel channels and compare, ferinstance, different demod topologies.
Here is the new motherboard with some unfinished modules:
Most of the components are SMT except where I want to easily swap opamps or caps. It's obviously not meant for high-performance or for outdoor portability but it's a lot better than an ACE breadboard.
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