VGA Interfacing AVR Microcontrollers

November 23, 2010 by Caleb Kraft 34 Comments

[Lucidscience] is back again, this time showing us how to push data to a VGA monitor from your AVR project. It turns out that it is pretty simple, requiring only n open port and a few resistors and diodes. Well, it is that simple for the most basic version which gives you 56×60 pixels. Of course he couldn’t live with that and had to expand. Version 2 outputs 240×240 resolution and has additional sram and a double buffer making animations smoother and flicker free. As usual, the project is quite well documented with photos of the entire build process and schematics for you to build your own. A video of version 1 and version 2 are available after the break.

[via HackedGadgets]

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AVR Programming 04: Writing Code, Etc.

November 19, 2010 by Mike Szczys 24 Comments

Welcome back to this fourth and final installment of the series. The first three parts should have been enough to get you off the ground, but a few more learning examples wouldn’t hurt. It’s also a good time to discuss some of the other things these little chips can do. Join me after the break to:

Expand the sample code, adding features to our simple program while I challenge you to write the code yourself.
Discuss AVR fuse bits, how to use them, and what to watch out for
Touch on some of the peripherals you’ll come across in these chips

As a grand flourish to the series, I’ve used the example hardware from this final part to build a bicycle tail light. Hopefully this will inspire you to create something much more clever.

Series roadmap:

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AVR Programming 03: Reading And Compiling Code

November 5, 2010 by Mike Szczys 41 Comments

In the last installment of our tutorial series we built a simple circuit on a breadboard and programmed an ATmega168 to make it run. That proves that you know how to follow directions, but the eureka moments of doing everything yourself are on the way. This time around you will get down and dirty with the datasheet, learning where each line of the sample code came from, and give your recently installed compiler a test drive. We will:

Talk about bitwise operators and how they work when coding for microcontrollers
Discuss C code shorthand
Review the sample code from Part 2 and talk about what each line of code does
Learn to compile code

If this is the first you’ve heard about our AVR Programming series, head back to Part 1 and start from the beginning. Otherwise, take a deep breath and we’ll being after the break.

Series roadmap:

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Mac SE Reborn As A Server And Mac Emulator

November 4, 2010 by Mike Szczys 27 Comments

[Sprite_TM] cooked up an amazing hack by resurrecting a Mac SE using a Dockstar and ARM processor. The retro hardware had a bad mainboard thanks to the corrosive properties of a failed backup-battery. He had been wanting to do something with the Seagate Dockstar and decided it would find a nice home in the Mac. But what fun is a dead machine housing a headless server? To add to the fun he included an ARM processor running a Mac emulator, along with all the bits to make the screen, keyboard, and peripherals work. When the Mac is off the Dockstar still runs as a server.

But one of the best parts is the floppy drive. It still takes floppies, but there’s no magnetic media inside of them anymore. Instead, he’s added an SD card slot and some protoboard in the space for the read head. The drive itself has had the read head transplanted for some pogo pins (hey, we saw those earlier today). When you insert the floppy, the pogo-pins raise up and contact the protoboard, connecting the SD card to a Teensy microcontroller.

There’s so much going on with this project we just can’t cover it all here. Things like a chemical cleaning to return the original color of the classic case, and building a converter so that the peripherals are USB compatible are just some of the pleasures awaiting you in [Sprite_TM’s] post. He’s also filmed a demo video that we’ve embedded after the break.

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Tiny USB Business Card

October 29, 2010 by Mike Szczys 43 Comments

[Frank Zhao] put together a USB business card. It’s even got the instructions printed right on the silk screen of the PCB explaining how it should be used. He based the design around an AVR ATtiny85 microcontroller. It runs the V-USB package that handles USB identification and communication protocols. The rest of the hardware is pretty standard, the uC draws power from the 5V USB rail, with a couple of 3.6V Zener diodes to drop the two data lines down to the proper level.

Once plugged in it waits until it detects three caps lock keypresses in a row, then spews a string of its own keypresses that type out [Frank’s] contact information in a text editor window (video after the break). It’s not as reusable as the mass storage business card because [Frank] didn’t breakout the pins on controller. But we still enjoy seeing business cards that make you stand out.

This is a great project to tackle with your newly acquired AVR programming skills.

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70 LED Matrix In A Jack-o-lantern

October 26, 2010 by Mike Szczys 23 Comments

What takes eight hours to solder and uses more shrink tubing that you thought imaginable? An LED matrix installed in a real pumpkin. When I mentioned that we’d like the LED pumpkin in last Friday’s post scaled up to a full LED matrix I had no idea it would be me doing the work. But [Caleb] and I thought it might be just the thing to present for the hacker’s favorite holiday.

Installed in the autumn vegetable is a marquee made from a 5×14 matrix of light emitting diodes. I spaced them by printing out a grid on the computer, taping it to the pumpkin, and drilling 70 holes in the front of the thing. The real trouble came when inserting all of the LEDs from the inside; each of them has four wires soldered to it, creating a net of black wiring. Above you can see it turned out great. This is a shot of it scrolling the message HAPPY HALLOWEEN.

Join us after the break for video of this prop. But we’re not just sharing the finished product. I’ll take you through the build process. Along the way you’ll learn the design considerations that go into an LED matrix and how you can use these techniques to build your own in any size and configuration you desire.

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RC Controlled Camera Takes Intimate Video Of Rodents

October 25, 2010 by Mike Szczys 27 Comments

[Leor] wanted to take some video of the wildlife in his yard, like this chipmunk or some hummingbirds, but every time he tried to get close it scared them away. His solution was to rig up a cheap video recorder to be radio controlled (PDF). The donor camera was a cheap SD card based eBay purchase that takes 720×480 video. [Leor] removed the SMD switches from the recorder’s PCB and wired up a 4066 quad bi-lateral switch IC in its place. An RC toy car donated the receiver transmitter pair. The receiver signals are monitored by an AVR microcontroller which translates the commands in a proper set of button presses for the video. What you get is a controller that and turn the camera on and set to the proper mode, and the ability to start and stop the recording.

We’ve got some pics of the hardware after the break, and [Leor] posted a bit of the chipmunk video for your enjoyment.

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