I wanted to use power LED under fischertechnik. Unfortunately, these very high currents need at voltages of 2 to 3.5 volts. It is usually assumed for voltage regulation Integrated circuits such as the LM317T. What's needed is a few passive components, a circuit board and a heatsink. For the same price you get now also finished step down converter included LED voltage meter. Since they have a high efficiency, it would also be suitable for battery applications.
So it was close to using the latest technology.
With the drop down regulator can also control motors or other loads.
Step 1: The LM2596 DC-DC Buck Step Down Converter Module
A finished LM2596 step down module you can get from about 4 €.
The LED voltmeter makes the voltage setting very comfortable. With the trim potentiometer accurate adjustment is possible.
The operation of LED's must not be exceeded the allowable current. Furthermore, the LED should do not heat above 80 degrees.
The most important data:
Input voltage range: 4-40 v (40 v to limit the highest voltage).
Output voltage range: 1.25V - 37V (decompression mode, input output must be greater than 2 V above).
Output current: 2 A continuous outputs.
Output power: the maximum 15 w.
Grain wave peak: 100 mv.
Voltmeter precision: ± 5 ‰ .
Static power: 20 ma
Button to switch measurement of the input or output voltage and LED indicates the current measurement of the input or output voltage.
Continuously adjustable output voltage range of 1.25V -37V, 4-40V input voltage range.
The input voltage is at least high than the output voltage of 1.5V?.
Step 2: Integration Into Fischertechnik
Adaptation to fischertechnik is very simple. A 45 x 90 mm base plate fits very well with the module. We drill 4 holes for M3 screws. 8 nuts hold the module at a distance. To the output terminals are two 2.6 mm jacks. We can hard-wire the cable as well. A piece of heat shrink tubing secures the two jacks in addition.
Step 3: Example of Use
Projection of colored shadows with the help of power LED.
I have used in the example 3 Watt LED. The glued heatsinks are unfortunately undersized. I have therefore limited the LED current to 300 mA. It is sufficient to achieve the desired effect
If you want instead of the LED control motors, it may be better to replace the built-in trimmer by a potentiometer.
Of course, it goes without fischertechnik. But fischertechnik saves me a lot of work in the workshop.