Announcing AASaver 2.1 — a versatile boost converter for AA/AAA batteries

This is a quick update that AASaver has been upgraded to version 2.1. It inherits all the capabilities of version 2.0, including built-in 5V voltage booster, flashlight LEDs, breadboard power pin headers, USB port (for charging USB devices), LiPo charger (with adjustable charging current). On top of those, version 2.1 adds a 3.3V LDO and a switch you can use to choose between 5V or 3.3V output voltage. This has been the main requested feature that was missing on version 2.0. Using an LDO (instead of changing the feedback resistors) has the advantages that the voltage booster and USB port always output 5V, while the 3.3V output is only effective on the LEDs and the breadboard pin headers. Here are some pictures:



For those who are curious what AASaver is: it’s a multi-purpose voltage booster for AA/AAA batteries. I came up with this idea initially when I was cleaning up a box of ‘dead’ AA batteries one day, and was surprised that many of them actually have pretty good output voltage, like 1.2 to 1.3V. Many AA batteries rejected from gadgets (e.g. remote controls and smoke alarms) still have plenty of juice, but these gadgets don’t have built-in booster circuit to bump the voltage up, so a lot of batteries are wasted this way. I was learning voltage booster at that point and had the idea of designing a multi-purpose circuit for AA batteries, so that I can harvest the remaining energy in ‘dead’ batteries for a variety of things, like lighting up LEDs, powering breadboard circuits, charging LiPo batteries etc. That’s how AASaver was invented. It’s not restricted to used or ‘dead’ batteries — if you plug in a fresh pair of batteries, you can also use it to charge your phone or other USB gadgets. It’s a really neat, useful, and inexpensive tool that everyone should have a few of these!

Below is the original video I made for AASaver. Keep in mind that the current version has a lot more features than shown in the video, including USB charging, LiPo charging. You can even modify it to become a solar charger.

With this new version, I’ve also prepared a more detailed User Manual, with assembly and usage instructions. We have just fulfilled an order from Micro Center so in the near future you may even find AASaver in the Micro Center retail stores 🙂

OpenSprinkler Pi (OSPi) Manufactured Locally at WAi

Back in April, I blogged about WAi (Worthington Assembly Inc.), a circuit assembly company located only 15 minutes away from where I live. They’ve got great reputation in the maker community, and have helped projects such as Tessel, RGB-123 LED matrices to take off. I am glad to announce that we’ve now partnered with WAi to manufacture OpenSprinkler Pi (OSPi), and the first batch of 200 boards just came out from a late-evening production yesterday. Check out these awesome videos Chris Denney took during the production:

Full-speed version

Slow-motion version

Some static pictures (taken with an outdated phone, sorry about the quality!). Picture captions: 1) tapes loaded onto pick-and-place machine; 2) first board came out of the reflow oven; 3) first board after AOI inspection; 4) me holding a stack of 25 panels.


Compared to manufacturing in China, using a local facility has the unbeatable advantage of quick turn-around time. The cost may be higher than made in China, but for an open-source hardware business like us, it’s critical to remain agile and be quick about making changes. I’ve been there — waiting for months for an order to ship from China, which was painful and stressful. By the time the shipment arrived, I already wanted to move on to the next version. With WAi, we may have found just the perfect solution for our need, and this is supporting local manufacturing too, win-win! 🙂