THE circuit shown in Fig. must represent the limits of simplicity for a metal detector – yet the design works surprisingly well. It uses just one 40106 hex Schmitt inverter i.c., a capacitor, and a search coil – and of course the batteries. A lead from IC1b pin 4 needs to be attached to a medium … [Read more...]
EVEN if you already have an electronic security system installed in your home or workplace, there is likely tobe a use for this Door Protector. With any security system, or even with none, it is important that all doors and windows should be protected by bolts, bars, grids or other physical means. … [Read more...]
SOME modern freezers contain alarms which sound if you leave the door open and allow the internal space to warm up. However, they do not work if the freezer suffers a power failure, which is a bit of a drawback. Making a temperature-sensitive circuit which can sound an alarm is not too difficult but … [Read more...]
" How to avoid having an unwanted rear entrance to your garage! "This is a device to aid you in parkiar in a garage by providing a visual and audible warning. It is easily set up by mounting it onto the wall at the end of the … [Read more...]
" Control your home from any part of the world "Do you want to control your TV or any other home appliances from any part of the world by just one click?Do you often forget to switch on or switch off devices while you leave your house?Are you … [Read more...]