ATmega324 Acts As A GPU For Homebrew Computer

[Quinn Dunki’s] homebrew computer project is moving up another evolutionary rung. She needs a more versatile user interface and this starts with the data output. Up to this point a set of 7-segment digits has served as a way to display register values. But her current work is aimed at adding VGA output to the system.

She starts off her write up by justifying the protocol choice. Although composite video would be easier to get up and running (we see it in a lot of AVR projects) [Quinn] doesn’t have a screen that will display composite video. But there’s also a lot of info out there about VGA signal generation. She delved into the specifics and even found a great AVR-based example over at Lucid Science.

The version seen above uses the 40-pin ATmega324. It’s a lot bigger than necessary for the example she put together, but in the future she plans to add video memory and will be glad to have all of those extra I/O pins. When it comes to video sync, timing is everything. She wrote the code to drive the display using assembly. In this way, she was able to look up the cycles used for each command to ensure that the loop is running with near perfect timing.

Antique Light Bulb Organ

Add a retro light show to any MIDI instrument with this Antique Light Bulb Organ, twelve 30 watt antique style light bulbs correspond with the 12 notes in an octave with a simple on or off action. The organ is also monitoring the pedals, so the lights will stay on as you use the sustain. Add in the natural slow reaction time of a light bulb and the effect is quite nice.

Along with MIDI instruments , you can also connect to a PC via USB allowing for remote control either with MIDI or OSC. On the hardware end there is a Atmega324P board that handles communication, user input and of course the lights. To switch the 120v AC current required by the lights twelve Sharp PR36MF22NSZF isolated solid state relays were wired up to some screw down light sockets also fitting the retro theme.

Lastly everything is placed in a nice fold up wooden cabinet, perfect for those long road trips to prevent breakage, but it also makes a nice place to put your keyboard while on stage.

Join us after the break for a quick music video that features this good looking light organ.

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Spinning POV Clock Done Oh-so-right

[Kizo] builtĀ an extraordinary persistence of vision clock. The design uses a PC cooling fan to spin the propeller-like PCB. As it goes around, a hall effect sensor synchronizes the illumination of the LEDs to draw the display. Power for the rotating electronics is transferred wirelessly via a transformer on the base and coil on the spinning board. The final version uses an ATmega324 microcontroller running at 20 MHz and has an IR receiver for changing the settings. The 3000 lines of code bring a lot of bells and whistles, including a menu system with a huge amount of settings from tweaking the clock display, to font selection for scrolling messages. Take a look at the demo after the break. The double-sided board looks like it’s pretty difficult to etch at home, but as you can see from the forum post (translated), [Kizo] did a great job on this build from start to finish. Continue reading “Spinning POV Clock Done Oh-so-right”

DPAC Put Your Alarm Clock To Shame

DPAC, the Dynamically Programmable Alarm Clock, goes far beyond what you would expect an alarm clock to do, yet we find all of its features useful. You can see there are four buttons at the bottom that control the menu scrolling. The second from the left currently reads “Sync”, a feature that the clock uses every 10 minutes but can be forced manually. This will check your Google Calendar, schedule an alarm for the next event while factoring in driving distance, traffic, and weather conditions. It’s got an audio system for radio and iPod operation, but also includes some home automation options. Using the X10 communication protocol it can turn on lights, start the coffee maker, and open the blinds as part of a gentle wake-up cycle. All of this is configurable through the clock itself, or via the web interface. The prototyping was done on an Arduino but the final version uses an AVR ATmega324 along with a Roving Networks RN-134 WiFi module (datasheet) for connectivity. Check out the demonstration video that [Eric Gaertner] and his fellow developers filmed after the break.

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