Description

CleverHand is a low-cost, highly modular, and open-source Human-Machine Interface (HMI). This system offer the possibility to record and process bio-signals (EMG, ECG, EEG, etc.), kinematics data (accelerometer, gyroscope, magnetometer, etc.), and simultaneously provide a real-time feedback to the user (vibration, LED, Electro-stimulation, etc.). The system is based on a modular architecture, which allows the user to easily add or remove modules to adapt the system to his needs.

Cleverhand is deigned primarily for research and educational purposes. It allows the user to easily set up a wide range of experiments, from simple EMG recordings to complex Human-Machine Interaction (HMI) experiments.

Details

CleverHand

Module	Bracelet factor

Description

Cleverhand is deigned primarily for research and educational purposes. It allows the user to easily set up a wide range of experiments, from simple EMG recordings to complex Human-Machine Interaction (HMI) experiments.

Requirememts

Constraint	Status	Comment
Wearable		Wifi feature in progress
>16 channels		Up to 256 channels (32x8)
>2kHz bandwidth		Up to 2.5kHz
>=16 bits resolution		Up to 24bits
Bipolar/Monopolar
Modular		1 to 32 modules by bus
Affordable		<10-30£ per module
Opensource

Features

The system is composed of a controller module and a set of HMI modules.

Controller module

The controller module is the core of the system. It is responsible for the communication between the HMI modules and the computer. It is based on a microcontroller (Teensy 4.1) and a communication module (ESP32). The controller module is equipped with a USB, ethernet and WiFi interface, which allows the user to easily connect the system to a computer. The controller module is also equipped with a microSD card, which allows the user to store the data locally.

HMI modules

The HMI modules are responsible for the bio-signal acquisition and the real-time feedback. The HMI modules are themeseleves composed of several sub-modules, which can be easily connected to each other:

Communication module: This sub-module is responsible for handling the communication between the different modules of the controller.
Sensor module: This sub-module is responsible for acquiring the signals (EMG, ECG, EEG, IMU, etc.).
Feedback module: This sub-module is responsible for providing a real-time feedback to the user (vibration, LED, Electro-stimulation, etc.).
Electrode module: This sub-module is responsible for providing the interface between the sensor module and the user (electrodes, accelerometers, etc.).
Interface module: This sub-module is responsible for extending the electrode module with additional features (Jack connector, flexible PCB, etc.).

List of modules

Module	Description	Link
Communication	Handles the communication between the modules of the controller.	Link
EMG ADS1293	Acquires 5 channels of EMG signals.	Link
EMG ADS1298	Acquires 8 channels of EMG signals.	Link
EMG INA331	Acquires 1 channel of EMG signals + 3-axis accelerometer.	Link
FES AO4882	Provides 4 channels of electro-stimulation.	Link
IMU ICM2094	Acquires 3-axis accelerometer, 3-axis gyroscope, 3-axis magnetometer.	Link
DRY Electrodes	Provides 16 channels of dry electrodes.	Link
DRY Flex	Provides 8 bipolar channels on a flexible PCB.	Link
Jack Connector	Provides a jack connector for the electrode module.	Link

Combinaisons of sub-modules

The HMI modules can be easily combined to create a wide range of experiments. Here are some examples of combinaisons:

Combination	Front	Back
Communication + EMG ADS1293 + DRY Electrodes
Communication + EMG ADS1298 + DRY Electrodes
Communication + EMG INA331 + DRY Electrodes
Communication + FES AO4882 + DRY Electrodes
Communication + IMU ICM2094 + EMG ADS1293 + DRY Electrodes

Modular architecture

The system uses a shared bus architecture, which allows the user to easily add or remove modules to adapt the system to...

Project Logs

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Yet another EMG bracelet

Aightech • 06/15/2023 at 21:55 • 0 comments

Here is the most recent form factor I am testing. It comprises a total of 11 modules, which results in 55 individual electrodes.

I use this opportunity to learn how to make some rendering on blender :D

Here the final result. I used FDM printing and flexible filament for the white curly band and I used SLA printing and transparent resin for the small protective case of each module.

SPI selection trick

Aightech • 11/23/2022 at 11:27 • 1 comment

SPI buses are very fast however the number of wires needed increases with the number of modules connected to the bus. In this project, we are limited by the number of connections as we cannot afford to have 3+16 lines just for communication.

A solution would be to create an addressing system to select a module on fewer buses. A standard addressing system requires a hard-coded address for each module. It could be done with pads to solder on each board to set their individual address. Unfortunately, this system is not very modular as it forces each module to be "differentiated".

A solution I came up with after chatting with my father is :

Addressing the module by their order on the bus.

The addressing system works on 4 wires. Each module read the 4 bits address present on the 4 wires and then increments by one the address for the following module. Each module is activated only if they read 0xF (0b1111, 15). Indeed, when the module tries to increment 0xf, it activates a carry bit connected to the chip select of the chip!

Here a schematics providing a visual explanation of the system:

LEDs testing

Aightech • 11/23/2022 at 10:01 • 0 comments

First versions

Aightech • 11/20/2022 at 12:14 • 0 comments

Some pictures of the previous iterations of this project

From very simple analogue OpAmp circuits I designed to amplify a single EMG signal, I went to create modular multichannel digital devices!

Discussions

CleverHand - EMG

Description

Details

CleverHand

Description

Requirememts