One minor annoyance when programming microcontrollers in-circuit, is that often quite a bit of PCB space is lost due to the programming connector. Furthermore, when you have to program many chips, repeatedly reconnecting the programming cable quickly becomes a chore. So when I found an article about constructing a programming pen that would help solve both of these problems, I decided to build one for myself.
The screen that we watch TV on at home has build-in speakers, but, because it’s actually a computer display, hasn’t got an infrared receiver. This made it impossible to set the volume with the TV receiver remote. I recently bought some Stellaris LaunchPad development boards and figured this was the perfect opportunity to make something useful with one.
For the limit switches on a custom 3D printer I’m designing, I want to try out some contactless sensors. I have chosen to use hall effect sensors, which are sensitive to a magnetic field.There are three different types of these sensors available. First, there’s the omnipolar hall sensor, which turns on when a magnet comes in its vicinity. Next is the unipolar one, which turns on as long as a specific magnetic pole is close enough, which pole depends on the sensor. Finally, there’s the bipolar hall effect sensor, which latches on when one pole comes close and only turns off when it senses the other pole.