ahmedragia21
Member
Hello,
I'm not that good at electronics, coming from software background but I studied EE.
I'm trying to replicate and use the same sensor matrix as shown in the product here
www.tekscan.com
The sensor matrix will be used for biting on it, and it's insulated. The resistance with small bite is around 100Kohm to 10Kohm. A Reset it its in megahoms.
Due to CE and medical problems I don't want a DC current that can hurt the patient, and the nominal voltage should be less than 1V.
So I designed the following circuit and not sure if there are problems with it, regarding ghosting, it's function,..etc Before I print it, I don't trust in myself.
Basically there will be a Square Wave Excitation from Teensy 4.1 Board, at 10khz, and I used ICL7660 for generating -5V, and TL072 and TL072 as PWM Buffer.
Shift registers with ULN2803 will select Rows/Colums to be sensed by the Current to Voltage Converter. Then digital lock in will be sensed by ADC and written in Software to measure the ADC value.
I'm not that good at electronics, coming from software background but I studied EE.
I'm trying to replicate and use the same sensor matrix as shown in the product here
T-Scan Training Software 9.0 | Tekscan
Due to CE and medical problems I don't want a DC current that can hurt the patient, and the nominal voltage should be less than 1V.
So I designed the following circuit and not sure if there are problems with it, regarding ghosting, it's function,..etc Before I print it, I don't trust in myself.
Basically there will be a Square Wave Excitation from Teensy 4.1 Board, at 10khz, and I used ICL7660 for generating -5V, and TL072 and TL072 as PWM Buffer.
Shift registers with ULN2803 will select Rows/Colums to be sensed by the Current to Voltage Converter. Then digital lock in will be sensed by ADC and written in Software to measure the ADC value.
