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Custom Power Supply for Lemax Products Answered

Curious if it would be possible to make a custom power supply for the Lemax Halloween town.  We end up with a tangle of wires every year, and I saw recently This on Amazon and thought it might work.  The only problem I run into is that the bigger Lemax products (houses and spot lights) use 4.5v where as the smaller figurines use 3v.  I've seen a lot of computer PSUs used for benchtop power supplies but none have a 3v or a 4.5v output.  I'm fairly competent with electronics, so I understand this might be more difficult than it's worth.  


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4 years ago

You problem with the PSU could be "fixed" the quick and dirty way if you don't need too much power in terms of amperes.
Starting with the 4.5V:
You get insane power levels from the 5V rail of a PSU, if you add a standard 107 diode in series this diode will have a voltage drop of around 0.7V.
Downside is the diode is only good for a max of 1A.
This means you should use multiple "diode outputs" limited to under 1A for the load.
For example connect 10 diodes directly to the 5V rail and on the other end of them you can connect 10 individual 4.5v users - from there it of course goes back to the negative rail of the PSU to complete the circuit.
Unused diodes can be left open with no harm done if you make sure they are not loose and can cause a short.
The 3V is a bit a tricky as the 3.3v rail won't give you much power at all.
Again, 3 1007 diodes in series will give a 2.1V drop and making it possible to use the 5V rail.
Same thing as above just with 3 diodes instead of a single one.
In bulk these diodes are dirt cheap so order a pack of 100 or so ;)

Other option would be to use two step down converters that you can adjust to the voltage you need.
The 1 and 3A modules are quite cheap on fleabuy, for 10 or 12A you need to pay a bit more.
If PSU and diodes/step down converters are in a casing it would not make any difference what you use but for a lot of Lemax thingies I would prefer to use the step down converter.

Small speaker terminal blocks offer a quick and easy way to connect what you need ;)