Help designing a data acquisition module

Question

I'm prototyping a shoe that reads the pressure distribution of a person's weight as they walk. In order to accomplish this, I need to design a Data Acquisition circuit board that will be compatible with an array of piezoelectric pressure sensors. I found a research paper that addresses the same engineering solution, and I need help digesting it. (I am fairly new to PCB design)

Here's the article: (See section 2.2 DAQ unit) https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0237090

PCB structure

" It comprises a Bluetooth module, set of Rx/Tx ports, voltage regulator, data processing unit, controller, A/D converter, and rotary switches. The voltage regulator was used to convert 3.7 V of Li-ion battery to 3 V as a system voltage. Each cell of the soft matrix film was selected by two rotary switches for data collection. The voltage signals of the cells were extracted from the voltage divider and then sent to the A/D converter channels installed in the microcontroller STM32 (STMicroelectronics, Geneva, Switzerland), where the voltages were transformed into force values by using a 12-bit A/D converter. Through the serial (Rx/Tx) port, the force values were sent to the Bluetooth module, and then the Bluetooth antenna wirelessly transmitted the force values to a remote receiver (e.g., smart-phone or laptop)."

How can I begin replicating this PCB? I have an arduino, access to PCB design software and a 600ドル budget.

• Voltage Spike: You come up with an idea of the components you want. Then draw up a schematic with those parts. then once you have the schematic you can start the layout of the PCB. You will have to find components that have the function of each piece of the block diagram. To describe how to do this whole project would be a too long a description for an answer.
• Gil: Without a proper schematic you cannot make a PCB unless it is done manually. Take a look at KiCad, it will work from schematic capture to creating the necessary Gerber files to make a PCB.
• Bruce Abbott: "How can I begin replicating this PCB?" - that won't be easy because no schematic is supplied and the picture is too blurry to see what parts were used. The block diagram isn't much help either (what are these 'rotary switches' and why are they separate from the 'multiplexers'?). Unless you can get more information from the authors you will need to develop your own circuit, and test and debug it before making the final PCB.
• Kartman: You can get bluetooth modules with Arduino support and probably forgo the stm32. With some research you might be able to find a suitable board that fits your budget and doesn’t require you to design a pcb.

Answer 1

You can do that pretty easily for 100$ or less.

You don't need the rotary switch, what do you want to have is analog multiplexers, there are plenty of them. Make sure they are low leakage current if your piezo has small signals.

Then simply use a common MCU with an A/D to convert the signal.

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If your piezo have a large enough signal option B:

Good analog multiplexers can be quite expensive, but some MCU have a lot of ADC input, given you have 16 sensors, you can find an MCU with 16 ADC input, some do have 30+ channels in the PIC32MZ series and you can even get rid of the multiplexers if the signal can be handled without amplification.

You can increase the ADC sensitivity by using a lower voltage analog reference, see the MCU datasheet.