To ease both the boredom and the desire to build something I decided to make a dimmer to go with the previously made LED-lights and tabletop fan. To make sure I get the job done in just one day I decided to take the KISS (keep it simple, stupid) approach and for now get along with just a single channel.
The housing is from an old 12 Vdc -> 230 Vac inverter (thanks akeeh for giving me this!). The case was otherwise perfect, but new front- and rear panels had to be made as the old ones were full of holes. After cutting the rear panel I draw the holes for the necessary connectors and started drilling....
11 holes later all the connectors and the mounting screws were on and the rear panel was ready for now. I may sand and/or paint it later, but right now I don't have time or room to do it.
The front panel was easier with just a single hole needed. I then installed a 5 kohm adjustable resistor and a large aluminum knob. I thought of adding a power switch, but then figured I didn't really need one. Again this is a thing that's easy to add later on if I add more channels and need to remove the front panel.
On the controller I went KISS all the way, it's the simplest kind of controller there is, done using only a single NPN-transistor and the potentiometer. Also note the 3-pin fan connector that connects the PCB to the potentiometer. Without this small detail it would be impossible to pull the rear panel + internals-assembly entirely out of the case.
Like with most of my projects nowadays I try to make the "product" as finished as possible in terms of ease of service and reliability.
The bottom 1,5 mm aluminum plate and the rear panel are held together with a piece of 2 mm thick aluminum angle (one can see the hex socket screws that hold the rear panel on the L-profile in the upper image). Disassembling the housing and pulling out the internals only requires undoing four screws.
So there it is, my weekend project of this week. It works very nicely with fans (voltage range about 6-12 Vdc), but I'll have to do some tweaks in order to get the LEDs nicely controlled. The transistor used is rated at 25 amps and the wires are thick enough for higher currents, so there's plenty of headroom for tons of leds :> Right now the power supply is a 12 volt transformer from an old router, but this can be easily updated to any ~10-16 V transformer if I need more power.
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