Hackaday Prize Entry: Scorpion DC-DC Voltage Converter

Finding the right wall wart or charger to go with an appliance might be a matter of convenience to you and I, but there are some people who really, really need the right charger, because not having it could mean a fire.

[marius] is a Romanian hardware engineer who moved to Papua New Guinea, where he had the opportunity to travel in the remote jungle of that country. There, he saw many people who used solar panels to charge car batteries for a 3W light bulb at night, their phones, or other conveniences that only need a few Watt-hours a day. Connecting car batteries directly to solar panels isn’t a smart idea, so [marius] set out to create a simple, very low-cost DC-DC voltage converter. He’s calling it the Scorpion 3.0, and it looks like a fantastic tool for low-income areas that are far off the grid.

The design of the Scorpion consists of a 3D printed enclosure, with one forked end containing some alligator clip leads, and a standard barrel jack on the other. In the middle is a character display showing the input and output voltage, and a simple rotary encoder for user interaction. The circuit for the Scorpion 3.0 consists mostly of a cheap, low-power MSP430 microcontroller managing the display, encoder, and a buck converter.

Designing something for off-the-grid usage means a few engineering challenges, and being in Paupa New Guinea, there are a few environmental considerations as well. [marius] is varnishing his 3D prints. No, it’s not going to be IP68 rated, but it helps. Making the Scorpion cheap is also a big consideration, most probably resulting in the choice of the MSP430.

It’s a great project, and an excellent entry to the Hackaday Prize. You can check out the demo video of the Scorpion below.

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Afroman Demonstrates Boost Converters

If you need to regulate your power input down to a reasonable voltage for a project, you reach for a switching regulator, or failing that, an inefficient linear regulator. What if you need to boost the voltage inside a project? It’s boost converter time, and Afrotechmods is here to show you how they work.

In its simplest form, a boost converter can be built from only an inductor, a diode, a capacitor, and a transistor. By switching the transistor on and off with varying duty cycles, energy is stored in the inductor, and then sent straight to the capacitor. Calculating the values for the duty cycle, frequency, inductor, and the other various parts of a boost converter means a whole bunch of math, but following the recommended layout in the datasheets for boost and switching converters is generally good enough.


[Afroman]’s example circuit for this tutorial is a simple boost converter built around an LT1370 switching regulator. In addition to that there’s also a small regulator, diode, a few big caps and resistors, and a pot for the feedback pin. This is all you need to build a simple boost converter, and the pot tied to the feedback pin varies the duty cycle of the regulator, changing the output voltage.

It’s an extremely efficient way to boost voltage, measured by [Afroman] at over 80%. It’s also exceptionally easy to build, with just a handful of parts soldered directly onto a piece of perfboard.

Video below.

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