Doc Brown’s Security Briefcase Needs Speed

If you just wait around long enough, the future becomes the past. And that’s happened to the “Back to the Future” future, as you probably all remember. But BttF-themed projects are still pouring in.

[ossum] sent us the link for his build of Doc Brown’s briefcase that only opens above 88 mph. His writeup is fantastically detailed, and worth a look if you’re interested in working with a GPS unit and microcontrollers, driving seven-segment LEDs with shift registers, or just driving too fast in an old Jetta. And there’s a video demo just below the break if you’re not a believer.


We’ve seen a lot of reverse geocaching lock boxes that only open up when you’re in the right place. This hack is the first that we’ve seen taking the first derivative. See where we’re going with this? Who will be the first to build a GPS acceleration-based lock? (Don’t get us started on jerk.)

16 thoughts on “Doc Brown’s Security Briefcase Needs Speed

    1. No kidding, I was petrified I was going to be pulled over while shooting the video. “Umm, sorry officer, it just looks like a bomb, but it isn’t… No I can’t open it… unless we hit 88mph”

        1. Its unlikely to be the kid suing more likely his parents or some lawyers talking them into it.
          Much like the “suing mcdonalds for hot coffee” stuff a decade back, its best not to believe the initial headlines as there’s normally more going on.

          Also the kid didnt “Hoax” anything.

          1. Instead of going to get his kid at the police station, Ahmed’s father held a press conferenc ein his front yard, complete with pizza for the reporters.

            They refused to pick up the clock for two months, while the MSM dutifully reported “police wont return ahmeds clock!”

            The school officials sat there waiting for a scheduled meeting while Ahmed’s father told his side of the story to the media.

            Ahmed is a minor his name was released by his family – not the school.

            The day after the event the family, beaming smiles, tweeted a selfie of them “on the way to their lawyer”.

            it is what it is. A kids prank or hoax followed up by massive adult-fail, as adults will fail.

            Kid was rich to begin with, or he would have been charged. A wealthy family is feared by the schools – while poorer families are made examples of.

          2. The woman in the coffee case was a senior citizen who got 3rd degree burns from the overheated coffee. If she’d taken a swig of it, it would have done to her esophagus what it did to her legs. Do a google images search for mcdonalds coffee burns. Hope you have a strong stomach.

  1. Something that would be interesting to try. Get a pair of radar gun testing tuning forks. They’re pretty common on eBay. One is stamped 35 MPH and the other (no kidding!) 88 MPH.

    Make a mount for a car to attach the tuning forks to the front like an old hood ornament. Drive at a radar gun at various speeds, with and without each of the tuning forks mounted. Do they make any difference in the speed reading?

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