IEC 60601 limits 100 µA maximum dc-leakage current through the body under normal conditions and 500 µA maximum under worst-case, single-fault conditions. An impedance circuit should not exceed that current.
- AD5933 12-bit impedance converter ($18) evaluation kit available ($68)
- User Guide with reference schematics
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Biopotential
- ECG (waveform)
- R-R (heart rate)
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Bioimpedance
- Resp (respiration)
- GSR (galvanic skin response, stress level)
- EDA (electro dermal activity)
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Max 30001G ($10) for Biopotential and Bioimpedance, evaluation kit available ($113)
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Maxim 30009 for Bioimpedance, evaluation kit available ($212)
| PART | Features | Resolution | Remarks |
|---|---|---|---|
| AD5933 | Single channel 3 wire | 12bit, 1Msps, 100kHz excitation | First Gen, 1024 point FFT, 1kOhm - 1MOhm |
| AD5940/41 | 2 channel, 4 wire | 16bit, 800ksps, 200kHz | Impedance spectroscopy |
| ADuC355 | 2 channel, 4 wire | 16bit, 800ksps, 200kHz | Impedance Spectroscopy, 26MHz ARM Cortex M3 MCU |
| MAX30002 | single channel, BioZ, 2 or 4 wire | 17bit | |
| MAX30009 | single channel, BioZ, 2 or 4 wire | 16 kHz - 806 kHz | |
| MAX30131/132/134 | 1-,2-,4- channel | 12 bit | |
| MAX30001G | single channel, 2 or 4 wire | BIOZ: 1-100kHz xx bit, ECG: xxbit | Impedance and Potential (ECG) |
For general reading: Analog Devices: Bio-Impedance Circuit Design for Body Worn Systems"
- Analog Devices AD5933 Evaluation Board, User Guide
- Munoz et a, 2022, A low-cost, portable, two-dimensional bioimpedance distribution estimation system based on the AD5933 impedance converterl
- AD5933 Datasheet
- Instructables: Body Composition
- Instructables: BIA 1
- Instructables: BIA 2
- Instructables: Thor 1
- Instructables: THor 2