Making Toys

Lie Detector

Lie Detector v 1.0

For our pulse sensor assignment, I wanted to do something with the data that revealed something a bit more personal about the person. For the Lie Detector, I went for an old carnival type of look. If the user’s pulse jumps above 75 BPM, the LOL shield displays the word “lie.” If the BPM stays normal, then a happy face is displayed.

Lie Detector v 2.0

I definitely wasn’t happy with the construction of the original prototype, so I attempted to make a more finished enclosure for this version. I decided to make a retro look and feel for the device. The actual enclosure is a wooden box. I decided to lose the LOL shield and use simpler, more universal feedback to let the user know whether or not a lie was being told. I drilled holes through the front for LEDs and capped it with red and green plastic tops. I also added a velcro strap to the actual pulse sensor, which dramatically increased the reliability of getting accurate pulse readings.

Lie Detector Final

What was lacking from the second prototype was there was no indication that the lie detector was working. I added in some LEDs on top to convey that part of the experience. To finish the look, I laser cut the words “lie detector” and hot glued them to the front. The user first straps themselves into the device by velcro-ing the pulse sensor to their index finger. They are asked a question, and after answering, the black button is pushed to begin BPM analysis. The LEDs on top blink to show that it is calculating, and then the result is displayed by either lighting up the red or green light.

While initially made for fun with friends, it could also be used in other practical situations as seen below.

Images from the process: