All this talk about 555 timers is causing projects to pop out of the woodwork like this one that reverse engineers a shopping cart security mechanism. The wheel seen above listens for a ...

Shopping carts are surprisingly expensive ... If you left the track, a rod passing through the wheel locked it. A third magnet would disarm the brake when you entered the store again.

When shopping for a garden cart ... Dump carts are four-wheel carts with hinged beds that tilt independently of the frame ...