Wish to know if someone is mendacity? It’s at all times so onerous to inform. [dbmaking] has whipped up a enjoyable little polygraph, in any other case referred to as a lie detector. It’s nowhere close to as complicated as those you’ve seen on TV, but it surely may be simply pretty much as good on the subject of discovering the reality.
The mission retains issues easy by specializing in two main biometric readouts — coronary heart price and pores and skin conductivity. With regards to the beating coronary heart, [dbmaking] went hardcore and selected an AD8232 ECG gadget, relatively than counting on the crutch that’s pulse oximetry. It picks up coronary heart indicators by way of three leads which can be identical to these they stick on you within the emergency room. Pores and skin conductivity is measured with a pair of electrodes that connect to the fingers with Velcro straps. The readings from these inputs are measured after which used to find out fact or a lie if their values cross a sure threshold. Presumably, if you happen to’re sweating rather a lot and your coronary heart is thrashing like loopy, you’re telling a lie. In spite of everything, we all know Olympic sprinters by no means inform the reality instantly after a run.
Does this work as an precise, viable lie detector? No, probably not. However that’s not simply because this gadget isn’t refined sufficient; industrial polygraph programs have been broadly discredited anyway. There merely isn’t a simple solution to correlate sweating to mendacity, as a lot as TV has instructed us the other. Take into account it a enjoyable toy or prop to play with, and an effective way to find out about working with microcontrollers and biometric sensors.
