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CD4001 (part two of ??)

For such a long time I resisted the lure of the logic chip - why should I bother when a microcontroller can do all that and more for little more than spare change?

Well, now that microcontrollers (if you can buy them) cost millions of dollars each and logic chips are still relatively cheap - that side of the equation has changed! 

But also I have to admit I've fallen a little in love with these "wire critters". One element of the change of heart has been reading Forrest Mims' excellent notebook series, many of which contain fascinating circuits based on single or combinations of different logic chips.

There are many useful circuits (non-microcontroller based) that can be constructed, such as the following button debouncing circuit made with the CD4001 (see last blog and video):

While playing around with some ideas for applications of "latching" circuits I decided that a long held issue of mine found in most school science laboratories may be addressed with a circuit involving this IC.

The problem has been that there is only one big red panic button in the average school laboratory used in an emergency to shutdown gas, electricity and/or water. I'd like to have one panic button at each "station" which can shut down the entire grid. 

To accomplish this I built a simulated version and it seemed to work both for a single station, but also for multiple stations as you would find in an actual laboratory.

The simulation worked fine, so then I constructed the circuit on a breadboard and ran it through its paces.

The lab tech at work reckons that the idea is a winner, but is worried about students pushing the big red button just to annoy everyone. That is an entirely possible (probable) scenario, but can easily be addressed with the usual carrot/stick training that we employ for other "dangerous" or tricky laboratory items.