Really Small(s) GPS

Hi peeps, I have been wanting to make a small GPS device (GPS receiver and some sort of screen) that I could carry around for a while now, but I didn’t want it to be too big, so I made this. Mission accomplished.

This unit is explained in the video above, but is basically a GPS receiver, 1 CR1220 battery for the RTC on the GPS breakout, one of my Square Inch of Goodness boards, one 128×32 OLED display, three 6mm buttons, and a 400mAh Li-Po Battery (from Sparkfun). It even has FTDI headers on it so I can update the firmware with ease (with my own FTDI adapter!). The awesome part is that all of those things fit in an Altoids Smalls tin, measuring 2.15″ (W), 1.35″ (L), and .56″ (H), or 55mm (W), 34mm (L), and 14mm (H).

The GPS breakout board is from Adafruit and uses the MTK3339 GPS module, and man does it work well. I have had other GPS modules that worked, but it was a fight. If you’re thinking about putting GPS in a project, use this. They also have a great library for it. They even have the raw MTK3339 GPS module if you want to use your board. Read the Adafruit product page for all the features, there are many.

The 128×32 OLED display is also from Adafruit, it works well and has the typical OLED crispiness. Very easy to read, even in sunlight, for the size and you can even multiply the text size if you want to.

So I’m going up to NY in a few days, and I wanted a new and exciting way to talk with the TSA folks, so I figured this would work. (kidding) If only Hollywood had not trained everyone to think a gadget with a few wires and a flashing red LED, that they didn’t understand, was a bomb.. ugh. (not kidding)

*UPDATE – there is a set on Flickr for this with teardown pictures.

*UPDATE #2 – Oops, I forgot to put the link to the code on Github. 0_0

Fast Voltage Switching FTDI Adapter

I have been working more with 3.3 volt projects lately and wanted to make programming them with an FTDI adapter as easy as possible. Sure you can switch most FTDI adapters from 3.3 to 5 volts (the FT232RL chip has a built in 3.3 output as well as logic level selection), but it involves scratching a jumper wire and soldering pads. This isn’t bad to do once, but to go back and forth is time consuming and rough on the boards.

So, I made my own FTDI adapter with an easily changed jumper for voltage selection. I also added a power LED to let me know that it’s plugged in and ready to go, threw in some RX and TX indicator LED’s and all required caps (read the data sheet), and mini SB jack. I ordered the boards from OHSPark.com, and as always, they were great.

*UPDATE* Now available in the store!

Eagle files are on my Github page, or you can grab just the schematic in PDF format here.

Adafruit has an FTDI Friend and Sparkfun has an FTDI Basic if your not up to soldering 28 Pin SSOP packages, or just want one. 🙂

A word about open source hardware

Open Source Hardware

So, what is open source hardware and why should I be interested in it? Open source hardware is simply hardware that is released in the wild along with CAD files (PCB layout data), documentation, and hopefully a tutorial on how it is set up and works. The wiki page is located here. The Open Hardware Summit is here.

Now, I was skeptical about this when I first heard about it because I thought,”If I want to sell my stuff, why give away the information I worked on?” I mean after all, aren’t we supposed to design something, then patent, copyright, trademark, and lock it in a safe? Thats the way to keep it ours right? After all, I worked on it, and I should get all the credit and all the profit right? I’m not giving my stuff away! But then I started thinking…

I thought about myself buying hardware and how I yearn to know everything about it. When I found Adafruit Industries and Sparkfun, I thought, “Whoa! Sweet! Cool hardware and full documentation!” Did I first get the urge to download Ladyada’s board designs and have them made myself, cutting the seller out of the loop? Of course not. I mean, sure the option was there, but I would rather just purchase a kit with everything I need. This way, I get something in my hands a lot faster, tested, and documented for my hacking. The cost and time is just not worth me making my own.  Now, wouldn’t I want to offer the same thing to my customers? Of course I would, that’s what attracted me to buying from Adafruit in the first place.

When a maker/hacker buys something, it’s an entirely different attitude that a “regular” consumer. For the most part, a “regular” consumer wants to get the best deal on whatever they are buying, and they want it to “just work”. Yeah sure, us makers/hackers want the device to “just work” also, but we also want to know how and why it works. If we have full documentation, schematics, tutorials, and access to forums, we can fully understand what we own. And then once we understand it, we can fix, modify, hack it to our needs.

With all that said, I’m sold. I want to buy all my gadgets open source (if they are available), and want to offer the same back to the maker/hacker community. I have really learned a lot from good quality open source companies and the communities behind them, and would like to give back what I can.

There is a big move of DIY electronics right now. Some of us have been doing this for years, and others have just begun, but one thing is for sure, making and hacking is growing like mad. There is all kinds of great information available right now, as well as tools like the Arduino to get people started as well as develop new things. So don’t just read this, go make something!

EDIT: I just noticed that Ladyada has a great page on this!