Welcome Magicians. This page explains how to operate the Internet Lie Detector, a card trick by Jim Bumgardner. The secret is still the same: the detector already knows the card before the spectator answers the first yes-or-no question.
Do not show this page to your intended audience.
You show a spectator the website and let them believe the machine can read truthfulness from their answers. They choose a favorite playing card, write it down, and keep it hidden from the computer.
After reading the instructions, you hand over the mouse to the spectator. From that point on, the spectator does all of the clicking, and the lie detector identifies every lie and truth correctly before finally naming the card.
The detector is not actually measuring lies. The first two mapped button clicks tell the program the suit group, suit, and rank before the spectator starts answering questions. The questioning sequence only performs a convincing reveal of information the machine already has.
If you would like access to the source code, or want a customized version, Jim can still be reached via krazydad.com.
Start at the main site. The first screen is nearly blank and shows the current wide Continue button. To unlock the trick, click just outside the button, not inside it. If you click on the button itself, the machine locks and displays the fake outage screen. This mechanism is intended to prevent casual inspection of the effect.
Once unlocked, the spectator sees the card-selection instructions. The standard Continue button on that screen is mapped into eight regions. That first mapped click communicates both the suit and whether the card is in the low range or high range.
The second mapped Continue button, on the “rest comfortably” screen, communicates the exact rank within that low or high group. After that, hand over the mouse and let the routine run by itself.
| Low Hearts |
Low Spades |
Low Diamonds |
Low Clubs |
| High Hearts |
High Spades |
High Diamonds |
High Clubs |
Example: for the Queen of Diamonds, your first click goes in the High Diamonds region.
| X |
| Ace | 2 | 3 | 4 |
| 5 | 6 | (7) | (8) |
Use this second grid only if the first click indicated a low card.
| 7 | 8 | 9 | 10 |
| Jack | Queen | King | Joker |
Jokers count as high cards. After this second click, the detector already knows the exact card.