Adjustable PWM IR Remote Switch

After having acquired quite a few LED strips from irreparable televisions, and having fun building circuits to drive them, it became clear that some way to control them in a more meaningful way would be useful. A simple on/off switch could suffice, but dimming would also be a nice feature, and perhaps means of remote as well as local control would be a nice addition. The easiest way to achieve all of this and maintain a small form factor would of course be to use a microcontroller.


After finishing recent projects which employed infrared remote technology, I decided that IR could be a good fit for this remote switch project as well. So now, the main element of the project has to be decided on; the right microcontroller. Having much experience with the ATMega328P, it would seem to be a natural choice, however, it is rather large in size for the desired from factor, and contains many more I/O than needed. This led me to consider another chip from the AVR family; the ATTIny85. Coming in the reasonable SOIC8 package, this seemed to be a good fit.


The idea now is to have the board employ PWM to control brightness, and be able to utilize a standard IR remote control to control these outputs. After capturing some key press codes, a IR remote can be re-utilized, eliminating the need for a separate remote control for the board if desired. Besides lighting, other loads could also be controlled, either with PWM, or standard on/off DC switching.


To power the low voltage stuff, a linear regulator that was capable of a 25v input was selected, to allow a larger range of input voltages for switching. A more than capable and somewhat chunky TO252 (T6009L) mosfet was selected for handling the switching, although other transistors could be used as well. A large physical button, and potentiometer were included for local control, and a IR sensor was added for intercepting the remote codes. An LED was added for visual feedback, and a barrel jack and screw terminals were added to top off the board. Capability was added to include a 433MHz RF control module, however this was never tested. For the fun of it, a variable strobe feature was added, because.. why not. To house the board, a simple enclosure was designed and 3D printed.