Want a two person self destruct button, but tired of pesky microcontrollers?

We all know that our precious cruisers/warships/assets can not fall into the wrong hands, and what better way to assure that information security than incorporating a self destruct button into the design? While the general premise is simple enough the only real way to make sure some crazy space-virus can’t infect your captain and force him to destroy your ship is to add a two button security system! Wait, what if it’s a computer virus?! Well [Andrea] has it covered with this two hand hand control switch. We guess you could also just use the scheme to flip on a dangerous piece of equipment, since it forces the operator to remove both hands from the machine to operate the buttons, but where is the drama in that?

The buttons are timed using a combination of voltage dividers and caps to activate transistors, one to activate the 555 timer and another to disable the button input after a half second or so. Since it’s all resistor capacitor timing your circuit may require just a bit of tuning (or precision components) to get everything right.  There is a bit of an issue with using two people to trigger the output, as the second button actually operates the output relay directly. If the second button is held it will only remain active until the timer’s output is triggered, but if your second in command gets cold feet and releases the button before the core goes thermo, well, you’ll have an embarrassing jog to the escape pods.

Check the video after the jump to see [Andrea] fiddling around with the switch.

[Read more...]