This small circuit was developed to monitor the battery in a model hovercraft. The lift in the model is produced by an electric motor driving a fan. To avoid the possibility of discharging t... Read more
The circuit described here lets you control a cellar drainage pump so that it turns on when a preset liquid level is reached and turns off again when a different preset level is reached. The... Read more
Simple mechanical timers, which you can buy for a couple of pounds in every home improvement center, are suitable for switching something on and off one or more times per day. They can be us... Read more
Like all its counterparts, this network wiring tester comprises two elements, a transmitter unit, powered and fitted at the network start point, and a receiver unit, passive, which can be mo... Read more
Here are two circuits that make it possible to add up to eight detectors to an existing alarm system without running a single cable. Each transmitter has a unique number that is reported to... Read more
PP3-size 9 V batteries (IEC: 6LR22) have a considerably poorer price/energy ratio than 1.5 V AA (IEC: LR6) cells. This makes it all the more unfortunate when you accidentally leave a device... Read more
This circuit is a tester for flywheel-based ignition systems in small airplane engines. Basically, the same ignition coils are also seen in other small combustion engines used in/on mopeds a... Read more
During the past year, the author has built a standalone solar panel system, which included the construction of the panels themselves. Such a system stores the generated energy in a battery.... Read more
This small 12 V solar power source maintains its orientation towards the sun under control of a timer rather than the more usual light-sensitive arrangement. All the parts needed to build th... Read more
More and more electronic devices are portable and run off batteries. It is no surprise, then, that so many flat batteries find their way into the bin — and often far too early. When a set of... Read more
