1. 8 channel Voltage Measurement DAQ HAT for Raspberry Pi 12-bit:

https://www.mccdaq.com/DAQ-HAT/MCC-118.aspx#

2. 8 channel voltage measurement DAQ HAT for Raspberry Pi 16-bit:

https://www.mccdaq.com/DAQ-HAT/MCC-128.aspx

3. 1 channel 24 bit data acquisition system:

https://www.aliex

press.com/item/4001153456576.html?spm=a2g0o.cart.0.0.e6bd3c00nmjQ9j&mp=1

4. 4 channel 24 bit data acquisition system:

https://www.aliexpress.com/item/4000619593627.html?spm=a2g0o.cart.0.0.e6bd3c00nmjQ9j&mp=1

1. ECG sensor:

https://www.aliexpress.com/item/32911698347.html?spm=a2g0o.productlist.0.0.2cd15ae6b6ko9e&algo_pvid=2c9c5895-6110-46c0-a856-117ee8c00513&aem_p4p_detail=202109041155233466676478152720015084716&algo_exp_id=2c9c5895-6110-46c0-a856-117ee8c00513-0

2. High quality respiratory sensor:

https://www.aliexpress.com/item/1005003212843492.html?spm=a2g0o.cart.0.0.58f93c004oO6Y4&mp=1

3. EEG sensor:

https://www.aliexpress.com/item/1005001830535768.html?spm=a2g0o.cart.0.0.53b63c00R6Vjj3&mp=1

Matlab .m files also run in Octave, there are Python projects for physiological data analysis. It is possible to build a low-cost high-quality data acquisition systems for physiology on your own.