Using potentiometer instead of rotary switch

Using rotary switch in embedded design can save board space and in same time be very intuitive. With knob turn you can change parameters, go through menu and do all sorts of things. But rotary switches aren’t low cost solution. Since most microcontrollers already have ADC integrated, why not replace it with simple potentiometer. This is what Claude Haridge suggests in his example. There are several benefits of using potentiometer instead of rotary switch. First of all you only need one MUC pin. This already gives a chance to choose smaller micro. Also with potentiometer you dont have bouncing problem. Another benefit is that this is cheaper way. But you also loose some benefits of switch. First of all you loos detent feel of switching – hard to determine switching positions as you turn potentiometer. Another thing is that you need more sophisticated algorithm to read switch states. It is worth considering to use potentiometer in cheap solutions. Continue reading

Reinventing potentiometer with rotary encoder

Normally potentiometer is a passive electronics part which changes resistance when knob is turned. Kuala decided to make his own by using microcontroller and rotary encoder. Since it is digitally controller, he also attached three 7 segment LED indicators to display its current value. Operation is simple – microcontroller reads rotary encoder steps and increases/decreases value which then can be sent to another host device through I/O interface. If you need real resistance value, it can bu used along with digitally controlled potentiometer (like MCP4551). With rotary encoder select there may be several devices chained. Continue reading

This Carousel is not for You to Ride!

Do you remember the good old times, where your parents always brought you to the nearest funfair? You’re probably have a intimate bound with the carousel, as it’s one of the most popular theme in every funfair! Well, it’s time for you refresh your memory by building this MCU-controllable Carousel. Honestly, this isn’t a real Carousel, where you can have a ride on it, but it’s rather a MCU-controllable camera mount. Which means, you’ll need to find a panning head for this robotics projects (If you’re very familiar with the NXP LPC2148, then go ahead and use it to control this buddy). For building this project, you’ll have to prepare a few old CDs, where it will become the spinner. The axle of the MCU-controllable Carousel is actually a potentiometer, and this is for determining the position. For your information, the gear motor needed to be cobbled together with bits from a windup toy and old motor (You can buy the old motor online, if you didn’t have one). Ok, this MCU-controllable Carousel might look a little bit cumbersome, but… Continue reading

Electronic Drum Controller Will be Your Good Music Companion

If you a die hard fan of Drums, I bet you must be excited about this unique and DIY eDrum too. The required components for this project: A PIC16F877 RISC microcontroller Two line (16×2) LCD with backlight Some amplifiers Twenty-two analog inputs Two digital inputs Twenty-two input gain potentiometers Four control buttons One MIDI out One serial RS-232 out You need to remember the main goal for this project is to find and use the cheapest components, but can still be maintain results at the professional standard. By using the PIC microcontroller, the whole design becomes easier to expand and it’s also assembly language friendly as well. Below is the list of eDrum special features: 24 unique velocity sensitive trigger inputs One Hi-Hat stereo input One Snare Dual-Piezo input Six Cymbal inputs with the choke Four Mono Piezo inputs Two modes HiHat pedal operation One MIDI output Four control buttons The RS232 serial port Assorted memory for snapshots Various controllable parameters Since this project is mainly about the Trigger to MIDI conversion matter, therefore the eDrum will not offer any… Continue reading