Welcome to the Awesome Electronics workshop. I am Bre Pettis. I am Joe Grand and we get together every once in a while to show you really cool components that you can integrate in to your own projects. And because our attention span is so short, each video is only a few minutes long. We are totally smooth and efficient electronics podcasting ninjas. Today we are gonna talk about LCDs and GPS. Let’s get started with the LCDs and then GPS.
What’s Technical about Liquid Crystal Displays?
Well, they use liquid crystals and they display things. So, it’s all you need to know.
Awesome, you can find these things in all sorts of test equipment, watches and even this video camera right here. This is the display that we are using, it’s a serial LCD module made by Parallax. That means that we can send serial to it and it will all be displayed right there in ASCII characters. And the interface is really easy. So, you can use it with any of your favorite micro processors, which is just what we are gonna do now, right now.
Interface to these displays are really pretty easy. There’s only 3 pins you need to worry about. One is the data input from your micro processor, then you have power and ground. So, all the real magic happens on the actual display itself. Some circuitry here processes your commands and controls the LCD. The wires are all set up in our Parallax development board and now we are just gonna go ahead and plug it in and we are all set to program.
Here is some sample code that we’ve grabbed from the Parallax website and modified for our purposes. The code is actually really simple. We have our initialization routines. We are basically just setting up the LCD and our next step is actually the main loop of the program code, where we are sending commands to the LCD terminal and then sending some text that we want to actually display on the screen. Next, we have some cool animation that will actually scroll across the screen and then, we flash our back light and we are done. Now you’ve seen how easy it is to make LCDs say what ever you want.
Let’s integrate this with another component, yeah. GPS, yes, wow, G is for Grand, P is for Pettis and S, that’s a hard one. Operated by the US government, the Global Positioning System is 24 satellites that circle the earth 24 hours a day beaming location data to earth. A GPS receiver like this one can receive the information transmitted from a number of different satellites and then calculate very accurately its position, latitude, longitude, speed, direction, heading, cool stuff like that.
By the way, Joe designed this thing. I designed this module, it’ll be pretty easy to use. There’s only 4 pins that you need to hook up, power, ground, a serial line and an optional control line and there’s two different modes. One of them just transmits the raw NMEA data and the other one, you can actually send commands to this unit and get specific information back. I have got some wires here hooked up to power and ground and the SIO, serial input/output line which is hooked up to p15 which is one of the pins on the basic stamp.
Ok, here we go, just put this right in here, and we are ready to program it. Alright, we have loaded up the basic stamp with the GPS receiver test application, we can see all the information that we have received, here is our position, latitude and longitude and our altitude, we are 68 feet above sea level. Let us take both these projects and stick them together. See what happens, what do we have here? Your very own mobile GPS unit.
Alright, now this thing is all done, this thing is awesome, this is a GPS mobile unit, we are on the go. What can you do with something like this? Geocaching. It’s like a treasure hunt for nerds. We have printed some geocache locations from geocaching.com. We think we know where we are going. Let’s check it out and see if we can find some buried treasure.
One of the clues on this page is that the cash container is a small magnetic container. To me sounds like it stuck to something metal. So, we are looking for 37 degrees 47 minute 7.92 seconds. We are close but we can’t find it. So, we are decoding the additional hint. Clue, look down, song in le miserables. Is that helping us? Not at all. We are not cultured enough to understand that clue. We’ve revised our position and we think that’s its here. So, we have got a metallic box that I can’t get into, yes, yes, yeah we found it, yeah.
The way these things work is you can take something as long as you leave something. So, we are gonna take this cool little shrinky dink and leave something special for the next treasure hunter. You can totally do this. We have put together some schematics and all the sample of code that we have used on the show is available on the magazine website. So, put this thing together, go out, find yourself some booty. Have a good weekend. Magic fingers, magic fingers.