Review on RioRand 5 Pack Boost Converter Module: XL6009 DC 3.0-30 V to DC 5-35 V, Adjustable Output Voltage, Step up Circuit Board - 4A by Lynn Cole

Like some others I wanted to connect this to a Raspberry Pi. I put the Pi in a case with a small LCD that needed a 7-12V source. So take a 12V 1A wall wart and set one of them to 5V for the Pi, both work fine. And since it doesn't generate enough heat like a linear regulator, they work well in sealed cases. The PSU I am using erases. With a firm hand it can be set to 1/100 volt. Just solder some wires, two inputs connect to 12v power supply rail, two outputs connect to breadboard. And at $2 each, I'm not as worried about them breaking as I am with a real $200-$300 adjustable bench. Although it would still be nice to have.