A standard smartphone touchscreen is technically incapable of performing a real lie detector test:
Privacy, security, and legal risks
Genuine polygraph tests are conducted in person by trained examiners, using sensors on the chest, arm, and fingers (the fingers measure sweat, not the print itself). They’re expensive, not always accurate, and rarely admissible in court. free online lie detector test fingerprint
If you need to assess honesty or integrity, consider the following alternatives: using sensors on the chest