posts tagged with the keyword ‘usb’


The Badger: Waterproof USB Solar Panel

For the past nine months I’ve been working with Brown Dog Gadgets on a number of projects. It’s been mostly kits for the educational market, and I’ve done a lot of design work, and a bit of electronics prototyping, as well as writing code and lending a bit of advice about marketing. The most recent project is The Badger, a waterproof USB solar charger.

You may remember that two years ago Josh launched a campaign for solar chargers and it did pretty well. Since then he’s taken feedback and requests from customers and came up with The Badger, which offers a number of improvements, mainly the waterproof qualities, but it’s also a damn tough panel! We’ve run it over with a car, dropped a bowling ball on it, and shot at it with a gun. Oh, it also sat it water for two days, and worked just fine when we pulled it out.

8watt, 12watt, 16watt solar chargers

Why am I telling you all of this? Well, if you need a solar panel for any outdoor activity, these are pretty awesome. And, if you back the project, not only will you get a great charger, you will help fund my work. Yes, that’s right. Josh and I have a few projects we’d love to launch, but they depend on this Kickstarter campaign being successful. The more successful the campaign is, the more we can produce. What will we be creating? It may be programmable drawing machines, or creative robotics projects, or some combination of those (or something else.) Whatever is it, it will inspire kids (and adults) to learn and be creative and have fun.

So yes, get yourself a panel, or a power bank, or just toss a few bucks our way, and we’ll start cranking out some interesting kits. That’s the plan. Check out the video below, or head right to the Kickstarter page.


In case you’re wondering, this is what you see the first time a computer running Mac OX sees a Teensy (or other controller) acting as a USB HID device. (You know, like a keyboard.)

Mac OS X Keyboard

No worries, just hit the “Continue” button…

Mac OS X Keyboard

And then hit the little red dot in the upper left to close the window. Hopefully you’ll only see this the first time.

That’s it!


Teensy 2.0
Teensy is teensy

For the past few years I’ve been building devices that can emulate computer keyboards. Typically I’ve used the Teensy microcontrollers for this along with the Arduino IDE and the Teensyduino add-on. The things you can do with a Teensy to emulate a keyboard are very impressive! Basically, it’s the best way I know of to create your own custom USB keyboard.

Size matters – A-Star with Arduino Micro and Leonardo

When the Arduino Leonardo was introduced, one of the features I was interested in was the ability to emulate a USB keyboard. I never actually got a Leonardo to test this with, mainly because the form factor was too large for my projects. Sometimes shield compatibility is good, sometimes the smallest board wins.

Size matters!

I recently got a Pololu A-Star 32U4 Micro, which is a tiny (and cheap, under $13USD) board very similar to a Leonardo, once again using the Atmel ATmega32U4.

There may be a little bit of work involved in getting the A-Star up and running. There are drivers needed if using Windows, and (supposedly) a little more work to get things going with Linux. I had no issues with Mac OS X, but I’m pretty familiar with add-ons for the Arduino IDE due to using Teensyduino. You can also just pretend this is an Arduino Leonardo and that seems to work fine.

(I also can’t tell if the Pololu A-Star 32U4 Micro is open source hardware. They do have a bunch of files available, but I did not see an explicit “Open Hardware” note anywhere. It’s worth mentioning that the Teensy is not open source hardware. If that’s not a big deal to you, then it’s not a big deal to you. The official Arduino hardware is of course, open source.)

I’ll probably keep experimenting with the Pololu A-Star as a keyboard emulator for simple things, and stick with the Teensy for more complex things. I’ve also heard that the Teensy 2.0 will disappear in the future, which isn’t a huge deal, as the Teensy 3.1 is a big improvement over it, but the 3.1 does cost a bit more than the 2.0, so that’s one factor to consider when evaluating which board to use.

Have fun building your own keyboard!

Update #1: I’ve been talking to Pololu and they suggested the A-Star may actually be able to use the Teensyduino Keyboard libraries. I’m awaiting more info on this, as it would be an exciting development.

Update #2: It looks like the Teensyduino Keyboard libraries cannot be installed onto the A-Star, which is good to know. But don’t worry, I’ll be using the A-Star for some future projects anyway. ;)


MiFi Battery

You may remember me writing about the Virgin Mobile MiFi I picked up last year, and if not, that’s fine, but I’ve got an update, so you can just read this post…

For the most part, the MiFi has worked well as a 3G modem. Connection is hit & miss. Sometimes it’s good, sometimes it’s crap, but it mostly works. I ended up taking it on a recent trip which involved minimal airport waiting time and things went bad. I fully charged it up the night before using the AC charger, and all appeared well. So in the morning at the airport I turned it on, got a few minutes of use, and it died. I wasn’t too concerned since I was just wasting time at the airport.

When we got to our destination I plugged it into the AC charger and charged it up, except it didn’t charge up. The charger got warm, so I assumed it was working and decided the battery had died. Ugh. Annoying. Still, not a big deal, as I got free WiFi from our host.

So when I got back from my trip I ordered a replacement battery from Amazon, which was less than $5.00. When it arrived I determined that it was not the damn battery, but the damn charger! I confirmed this by charging it up using a USB cable. Also, the charger doesn’t get warm anymore, so I assume it’s dead.

Besides that whole adventure, I learned something new. See, I got the MiFi partly as a backup to my home Internet connection, figuring that if it went offline, I could use the MiFi. The only issue was that you connect to it via WiFi, which my Mac Pro does not have. I never charged the MiFi with USB before because USB charging is typically slower than AC charging, but now that I’m doing it all the time, I’ve found the secret to using it via USB instead of WiFi. (I say secret because I kept seeing questions as to whether it was possible, and people saying it was not.)

Disclaimer: I use a Mac… I’ve not done this under Linux or Windows.

MiFi Mounted

Plugin the MiFi, and you will see it mounted in the Finder. Now, for many USB devices if you just want to charge them, you unmount (eject) them, and they keep charging.

MiFi Mounted

Here’s the trick with the MiFi… Eject it! Once you do, it’ll show up as a new network connection and you can see it in the Network Control Panel, and you can click the “Connect” button.

MiFi Prefs

Hey, we are now connected! You can see the send/receive data, and if you click the “Show in menubar” checkbox, you get a handy little menu. (I didn’t need to fill in any values like the account name or password. It seems to load them all properly from the MiFi somehow.)

MiFi Menu

I’m still not 100% sure it charges up while using it in this fashion, so a bit more testing is needed, but hey, it’s progress…

Update: I’ve got an addition to what is posted above.


I tried the above on another Mac Pro I have and it did not see the MiFi until I ran the installer you see when you first mount it. After that, it showed up fine in the Network Control Panel, but the magic values were not filled in. (I also did not reboot, like the installer asked me to.) I ended up getting the Account Name from connecting to the MiFi (using WiFi) and finding it under the WWAN -> Diagnostics menu (listed as NAI) and the password was my 6 digit account pin. A bit more hassle, but now you know where to look.



This is Charlotte. Charlotte is a kitten. Kittens are cute. When Charlotte is good, she eats out of her food bowl. This is what a kitten should do.

Chewed USB Cable

Sometimes Charlotte is bad, and chews on things she should not chew on, like a USB cable. Bad Charlotte! I’m now out one USB cable.

Luckily, that was just a USB extension cable, and not the iPad cable that was plugged into it.

Since Apple is a little picky about who can manufacture iPad cables, I’d prefer not to have to buy replacements unless I really need them.

Tubing + X-Acto Knife

Luckily, my local hardware store has this great tubing that is just 23 cents per foot, and I’ve got an X-Acto knife.

My plan was to just slice the tubing open and then push the iPad cable into it. Simple enough, right?

In my first attempt I tried to use a steel ruler to get a nice straight line on the tubing, but that didn’t really work, and it was much easier to just freehand the cut. I will warn you that I have a BFA in Graphic Design, so I’ve been using X-Acto knives for well over 20 years. If you’re not as handy with them, be careful when you cut your tubing.


Here’s our new improved cable, with a protective covering. I showed it to Charlotte and she tried to chew on it, but either she didn’t like the taste, or figured out she was not going to chew through it. Either way, I win.


One tip: when you cut the tubing to the length you need, cut it just a bit longer, so you can cut it to the exact length after you’ve fed the cable into it. I managed to cut the first one I made just a little too short, though it was easy to fix with a very small piece of tubing added to the end, and then held in place with some clear tape.

I’m hoping once Charlotte is out of her “chewing” phase I can do away with the tubing, but for now, it works quite well.

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