Register now After registration you will be able to apply for this opportunity online.
This opportunity is not published. No applications will be accepted.
Optical sensor development for heart-rate sensing
What optimizations are necessary to make reflective PPG sensors reliably work on tissue with limited blood perfusion?
Note: Candidates should have experience in hardware design (analog circuits, embedded systems, and basic signal processing).
Keywords: Hardware Design, PCB Design, Embedded Systems, Sensors, Signal Processing
Photoplethysmography (PPG) is used in variety of devices to monitor heart rate and sometimes blood oxygen saturation. Medical devices usually work transmissively by placing an LED on one side of the finger tip or ear lobe and use a photodiode to measure light transmission to the other side of the tissue. Wearable device such as watches usually measure reflective PPG by placing the photodiode next to the LED and measuring the reflections from the skin.
Reflective PPG can theoretically be used at any location on the body where the sensor can be placed directly on the skin. However, the signal quality is low in places where there is little blood perfusion (e.g. on the chest where the sternum shields the tissue below). In this project you will investigate new combinations of light emitters, photodiodes, amplifiers, and ADCs to maximize signal quality, reliability and amplitude in such body locations.
Existing work points towards the use of large photodiodes and multiple LEDs in such applications. However, there are various trade-offs that we will have to consider when designing such a sensing device as increased sensitivity also increases the risk of maxing out the photodiode or ADC. Moreover, we are interested in acquiring PPG at different wavelengths which may add complexity to the design.
_Note: Candidates should have experience in hardware design. Experience in analog circuits, embedded systems, and/or signal processing is very beneficial._
Photoplethysmography (PPG) is used in variety of devices to monitor heart rate and sometimes blood oxygen saturation. Medical devices usually work transmissively by placing an LED on one side of the finger tip or ear lobe and use a photodiode to measure light transmission to the other side of the tissue. Wearable device such as watches usually measure reflective PPG by placing the photodiode next to the LED and measuring the reflections from the skin.
Reflective PPG can theoretically be used at any location on the body where the sensor can be placed directly on the skin. However, the signal quality is low in places where there is little blood perfusion (e.g. on the chest where the sternum shields the tissue below). In this project you will investigate new combinations of light emitters, photodiodes, amplifiers, and ADCs to maximize signal quality, reliability and amplitude in such body locations.
Existing work points towards the use of large photodiodes and multiple LEDs in such applications. However, there are various trade-offs that we will have to consider when designing such a sensing device as increased sensitivity also increases the risk of maxing out the photodiode or ADC. Moreover, we are interested in acquiring PPG at different wavelengths which may add complexity to the design.
_Note: Candidates should have experience in hardware design. Experience in analog circuits, embedded systems, and/or signal processing is very beneficial._
Develop a sensing setup for PPG that works on tissue with limited blood perfusion.
Develop a sensing setup for PPG that works on tissue with limited blood perfusion.
