DIY for Electronics

When microcontroller circuits interact with real life, switching lamps, motors or solenoids might become necessary. Switching such "non-digital" loads is usually a bottle neck in DIY projects, because nobody wants to have 230V or 110V swirling around on his perfboard.
Driven by the need to control a big lamp for time lapse shooting with the SmaTrig I designed a compact power switch useful for DIYers and electronics hobbyists. In the following I'd like to share with you the thoughts and ideas that went through my mind during the development of the device and provide you all data necessary to build your own switch.

Please google on if you are a pro looking for a high-end heavy duty product...
Read the following if you are an electronics hobbyist and need something for occasional use. This short article describes how to build your own super simple vacuum tweezers at virtually no cost. It's perfectly suited for positioning small SMD resistors or caps and works much quicker than conventional tweezers.

In this article a simple inductance meter is presented. It comes in handy when winding your own coils or transformers as needed in switching power supplies. It becomes even necessary for winding flyback transformers where the air gap must be adjusted. The oscillator circuit presented here is not my own creation, it can be found on various web sites. My contribution is the PCB design, the additional range switch and the buzzer.

When programming microcontrollers debugging is inevitable. Options like JTAG or DebugWIRE exist, but they are usually too expensive for most entry level DIYers. Another simple and controller-independent option is to utilise the USART for debugging. It's integrated into nearly all of today's microcontrollers. The only problem here is to convert the two serial signals RXD and TXD from the controller levels, usually TTL, to the EIA-232 levels as found in the serial port of every PC. Fortunately there is the MAX232, which converts signals between both levels.
This article describes how to build an extremely compact converter circuit built around the MAX232. With a size of just 14 x 17 mm (0.55 x 0.67 inch) the PCB is small enough to fit into a D-SUB plug housing