Bajdi made this DIY lab power supply and wrote a post on his blog detailing its assembly:
My DIY lab PSU has 10 binding posts in total. The ones on the left provide 12V, 5V and 3V3. The 12V output comes straight from the laptop power supply. The 5V and 3V3 are provided by a KIM055L and a KIM035L module. These can output 5A of current. The other 4 are the outputs of a LM2596-adjustable and a XL4015 regulator. The LM2596 is a simple adjustable voltage regulator board. I desoldered the trimpot and soldered a regular potentiometer to it.
The XL4015 breakout board is setup as a constant current regulator. It has 2 trimpots to set voltage and current. I again desoldered the little trimpots from the board and soldered 2 potentiometers to it. I fitted the 3 potentiometers to the front plate and added 3 nice buttons so I can easily adjust them.
The left panel meter shows the output voltage of the LM2596, the right panel meter displays the voltage and current of the XL4015 output.