Want to know if somebody is lying? It’s always so hard to tell. [dbmaking] has whipped up a fun little polygraph, otherwise known as a lie detector. It’s nowhere near as complex as the ones you’ve seen on TV, but it might be just as good when it comes to finding the truth.
The project keeps things simple by focusing on two major biometric readouts — heart rate and skin conductivity. When it comes to the beating heart, [dbmaking] went hardcore and chose an AD8232 ECG device, rather than relying on the crutch that is pulse oximetry. It picks up heart signals via three leads that are just like those they stick on you in the emergency room. Skin conductivity is measured with a pair of electrodes that attach to the fingers with Velcro straps. The readings from these inputs are measured and then used to determine truth or a lie if their values cross a certain threshold. Presumably, if you’re sweating a lot and your heart is beating like crazy, you’re telling a lie. After all, we know Olympic sprinters never tell the truth immediately after a run.
Does this work as an actual, viable lie detector? No, not really. But that’s not just because this device isn’t sophisticated enough; commercial polygraph systems have been widely discredited anyway. There simply isn’t an easy way to correlate sweating to lying, as much as TV has told us the opposite. Consider it a fun toy or prop to play with, and a great way to learn about working with microcontrollers and biometric sensors.
This is effectively an E-meter if held in each hand?
I really do wonder how they were made before digital ICs or perhaps they were never analogue
An e-meter is nothing but a simple lie detector.
They were analog. Very easy to make. It is nothing but an overly complicated ohmmeter with a knob to set the reading to zero. Deflection from zero means a lie.
Lie detectors and e-meters respond mostly to how much you are sweating – which can change due to lies, but can also change for a zillion other reasons.
Xemu hates me this I know
For L. Ron Hubbard tells me so
Be we will fight his evil plans
with jumper cables and tin cans.
Yes Xemu hates me.
Yes Xemu hates me.
I paid 10 grand to know.
Can this device be connected to a TV to indicate the bias level and accuracy of certain “news shows”? I do not quite remember the exact name of such a “show”, it’s on the tip of my tongue, it sounds a bit like Samantha Fox and screws although I can’t remember what Sam had to do with construction but I digress. I just want to connect it to my TV, that’s all.
Just use a voice stress lie detector and listen to the lies :) There are a number of handheld and software models for pc and phone. YMMV but it does do a pretty good job on day to day speech. Now with the news they are performing their delivery so things will probably be a bit off due to them performing. It was Samantha Bee you were referring to and yes even normal people could see what a biased hack she was (I had forgot about her). She started on TDS, so it wasn’t a surprise for the lean but the pieces I felt were pretty childish and did nothing to further the cause of the stories buried beneath them on the few occasions I did watch. My child had more profound arguments about who was next on the slide at the playground lol.
Catching people lying is easy, as long as you don’t mind a lot of false positives.
How can you tell if any politician is lying? When their lips move.
Old joke, but still pointy.
See, now I just want to build one that has all the appropriate hardware for the sensors and instead decides lying or not with a rng. As long as it’s at least close to a true 50% probability, I’ll be doing about as well as the professionals ;)