PPG & ECG sensors work with the ADS1115 4 channel 16 bit chip, but how is it with EEG sensors?

Last Updated on August 10, 2023 by pg@petergamma.org

Heart beat monitoring works with PPG sensors:

https://www.theengineeringprojects.com/2023/01/heartbeat-monitoring-system-with-ads1115-raspberry-pi-4.html

PPG & ECG sensors works with the ADS1115, but we did not yet find any EEG project which use the ADS1115 after a first quick google search. Several years ago, we asked Scott Harden if it was possible to replace his ECG chip for instance with an EEG sensor, and his answer was yes. So why should it not be possible to attach a TGAM module to the ADS1115? If this is confirmed, it could reduce the costs for low-cost high-quality EEG devices as for instance those based on OpenBCI modules dramatically.

An ECG device with the ADS1115 can be found here from Pukhraj Dhiman, a name which sounds as if it was from India:

https://www.hackster.io/pukhrajdhiman/dnn-based-homemade-ecg-a4259a

Developers from India are known to develop affordable devices for physiology.

ECG, EEG & ECG sensors can usually be replaced by each other in devices like Bitalino, Scott Harden, Sound Card ECG. With the Bitalino boards, we have ECG, EEG & MEG sensors. But with OpenBCI no sensor modules are attached for ECG; EEG, and MEG as this example shows:

https://docs.openbci.com/GettingStarted/Biosensing-Setups/ExGSetup/

What is special about OpenBCI Cyton for instance is, that it uses the Texas Instruments ADS1299 EEG chip which offers 8 channels in parallel, which makes those especially suitable for EEG which often have many channels in parallel. But if we choose InfluxDB as our database which offers many channels in parallel as well, why should we choose the expensive Texas Instruments ADS1299 chip for our project?

The Meditation Research Institute Switzerland (MRIS) needs your help to develop a mobile multi-sensor data acquisition system

• In this calculation we do not have to forget that devices based on the ADS1115 additionally need EEG chips which are currently available for around 20 USD:

https://de.aliexpress.com/item/1005004344005084.html?spm=a2g0o.productlist.main.3.540a157boTfB9r&algo_pvid=4ffd9d92-89f0-4b5c-ad3d-dc4c99a6ba44&algo_exp_id=4ffd9d92-89f0-4b5c-ad3d-dc4c99a6ba44-1&pdp_ext_f=%7B%22sku_id%22%3A%2212000028982844996%22%7D&pdp_npi=2%40dis%21USD%2130.16%2119.6%21%21%21%21%21%402102196716737499325344784d06c2%2112000028982844996%21sea&curPageLogUid=yMMYvdALULT3&gatewayAdapt=glo2deu

• As well as The AD8232 ECG chip which is available for 3 USD:

https://de.aliexpress.com/item/1005005600528597.html?spm=a2g0o.productlist.main.19.5b25dc43Ul4znF&algo_pvid=8a1f961d-1f5d-47ba-9439-eaee9ccd518c&aem_p4p_detail=202308092242059307348927814280003069585&algo_exp_id=8a1f961d-1f5d-47ba-9439-eaee9ccd518c-9&pdp_npi=4%40dis%21USD%212.55%212.55%21%21%212.55%21%21%402103224116916461255912224ebae4%2112000033705823885%21sea%21CH%21777421489%21&curPageLogUid=HF4erG62DFSK&search_p4p_id=202308092242059307348927814280003069585_10

These are complicated and sophisticated calculations, which chip sellers certainly did before us, so that all options cost about the same. But all this confusion shifts our attention toward physiological sensor devices like the Apple watch which can be streamed into InfluxDB, as the following example shows:

How to build a a mobile physiological data aquisition system with InfluxDB, the Apple watch, ECG & EEG running on a Raspberry Pi?

And makes us withdraw from devices with an unclear future, toward software with a growing community like Home Assistant and toward questions how physiological sensors can be attached to it. Home Assistant is not developed for ECG, EEG and MEG, but we think it is a good starting point for experiments. Several developers did before us these kind of experiments and attached sports heart rate sensors to Home Assistant. Sports sensors are the most popular heart rate monitors, and Home Assistant is the second most active Python application, so why not start with Home Assistant and sport heart rate monitors which both are very popular?