Have you ever been in a situation where you needed to power your 9V or 12V gadget, but there was no power outlet for your adapter? So have we. That's why we created the FemtoCow™ USB912™ adapter.
What is it?
FemtoCow™ USB912™ is a DC to DC converter that converts 5V from any USB port to 9V or 12V, selectable by a switch. It has a standard 5.5/2.1mm output connector that will fit most electronics. The amount of current it can deliver depends on how much the USB port can provide. It provides about 1/2 the port's amperage in 9V mode, and about 1/3 the port's amperage in 12V mode. A standard USB port can provide up to 500mA, which is enough for small projects. For extra power you can power your FemtoCow™ USB912™ from a portable USB charger battery pack. Those deliver up to 2.1A and it will make your project more portable too.
What have we done so far?
For our first prototype we soldered a USB cable to an off-the-shelf DC to DC booster with variable output. It worked but it was large and you couldn't tell what output voltage had been set from a previous project without measuring it.
For our second we made our own booster, small with two preset voltages, 9V and 12V which are the most commonly used. We selected an efficient, low EMI DC to DC booster IC capable of delivering up to 1A of current with programmable output voltage. We have been using our second prototype for about a year.
We've now made a third prototype based on the second with some improvements. That third prototype is the basis of the FemtoCow™ USB912™ you'll get.
Why do I need one?
This is a must-have item for your toolbox. You can use it to power your 12V electronics from a USB charger battery to make them portable. You can showcase your device without an electrical outlet. You can create an isolated 12V power supply when you power it from a battery or a laptop running off a battery. USB912™ doesn't provide isolation by itself though. Take one with you when camping. Power a WiFi extender in your backyard without having to use an extension cord. Some WiFi routers require too much power and cannot be powered this way. There are so many possibilities.
USB912™ comes with 5.5/2.1mm jack with positive center. That works for many devices, but not all. With a set of barrel adapters you'll have what you need to power devices that take a different plug.
- $20 - 1 USB912™ adapter
- $30 - 1 USB912™ adapter + 1 set of barrel adapters
- $40 - 2 USB912™ adapters + 1 set of barrel adapters
- $60 - 3 USB912™ adapters + 1 set of barrel adapters + custom output voltages
- $80 - 5 USB912™ adapters + 1 set of barrel adapters
- $180 - 10 USB912™ adapters + 1 set of barrel adapters + custom output voltages + custom PCB color
Some reward levels have an option to choose a custom output voltage. You can choose any two values between 5V and 32V. Default is 9V and 12V. Higher voltage on the output also means you can draw less current from it.
My original goal was to create the adapter as small as possible capable utilizing 2A USB power bank. During testing I found that the adapter gets too hot when drawing full 2 Amps because it's too small and can't dissipate the heat very well. I could make it bigger with a heatsink, but that would defeat the purpose. I wanted to have a small and handy USB 9V/12V adapter. Therefore I had to limit the input current to about 1.1A In addition I'm going to add a thermal protection that will limit the current even further if the adapter gets too hot. Here is a current specification and capabilities. It shows maximum output current based on input current and output voltage.
I'll work on the output ripple to get it down a bit. I made a new design and I expect to receive the new boards in a few days. I expect a better thermal performance, I added a thermal protection and an extra output filter. The max output current should remain about the same as before. The whole board will be probably encased in a heat shrink sleeve.
USB912 is meant to be powered from a USB power bank capable of delivering 2A. It is also possible to power it from a USB port on a computer, you need to make sure the USB port meets your power requirements. Do not overload the adapter or a USB port.
If our Kickstarter exceeds $6000 we'll include 9V battery adapter like this one with every reward that includes USB912™. It will let you power a device that requires 9V battery, like a portable radio, directly from a USB port, effectively emulating a 9V battery.
Risks and challenges
I've successfully finished one kickstarter project before, I have experience with small electronics design and manufacturing. If it gets extremely popular, I will create another reward tier for a second batch to accommodate manufacturing capabilities which will ship in a second wave.Learn about accountability on Kickstarter
- (30 days)