WAV Playback With An ATmega32

February 29, 2012 by Mike Szczys 16 Comments

[Vinod Stanur] just finished another hobby project by building a WAV audio player using a microcontroller. He had started development a while back using a PIC microcontroller. But the chip he was using didn’t have enough SRAM to allocate as a playback buffer. When he got his hands on an ATmega32 his mind turned back to the project and he saw it through to the end.

He takes advantage of what he learned on several earlier builds. He’s using a TV remote as input, just like his Snake game did. Storage is provided by an MMC card, a trick he perfected with this voice recorder project. Instead of using a FAT library, he uses his own code to read the linked-list (File Allocation Table) for sector addresses, then he parses the WAV header and processes the file accordingly.

Playback uses two 512 byte buffers. One is feeding the output while the other is being populated from the memory card. When the output buffer is exhausted the two are swapped and the process continues. You’ll find [Vinod’s] demo of the project after the break.

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Up Your FPGA Game By Learning From This LCD Control Prototype

February 22, 2012 by Mike Szczys 10 Comments

[Cesar] recently got a PSP display up and running with his FPGA development board. That’s a nice project, but what we really like is that he set aside a lot of time to show how it’s done every step of the way. This isn’t just a tutorial on that particular screen, but an overview of the skill set needed to get any piece of hardware working.

The screen itself is a Sharp LQ043T3DX02; a 480×272 TFT display with 16 million colors. Not bad for your project but when you start looking into the control scheme this isn’t going to be like using a Nokia screen with an Arduino. It takes twenty pins to control it; Red, green, and blue take sixteen pins, four pins are used for control, the rest are CK, DISP, Hsync, Vsync.

Wisely, [Cesar] designs his own interface board which includes the connector for the ribbon cable. It also has drivers for the screen’s backlight and supplies power to the device. With hardware setup complete he digs into the datasheets. We just love it that he details how to get the information you’re looking for out of this document, and shows his method of turning that first into a flow chart and then into code for the FPGA.

Who Couldn’t Use A Little More Screen Space?

February 21, 2012 by Kevin Dady 23 Comments

Text LCD’s are handy for any occasion, a printer port on your PC is also darn handy as well. Mix together and add in a splash of linux and you get a very handy Linux device driver for a 16×2 LCD connected to the parallel port.

Electrically the LCD is wired up in a typical 4 bit mode, this allows the parallel port to use its 8 bit data register to write data, but also control the Register Select and Enable pins. Next is to make a module for linux to use, it seems like pretty standard fair for this type of screen.

Make the driver, insert the module so it can be loaded, and add a node so you know where to find it later, and your only an “echo Hello > /dev/my_lcd” away from finding all sorts of creative uses for your new external display.

Build Your Own 4-channel Logic Analyzer

February 7, 2012 by Mike Szczys 26 Comments

If you’re just getting into hobby electronics chances are there are lots of tools you’d like to get you hands on but can’t yet justify the purchases. Why not build some of the simpler ones? Here’s a great example of a 4-channel logic analyzer that can be your next project and will add to your arsenal for future endeavors.

As you can see, [Vassilis’] creation uses a cellphone-sized LCD screen as the output. It is powered by four rechargeable batteries and driven by an ATmega8 microcontroller. He’s designed the tool without power regulation, relying on the ATmega’s rather wide range of operating voltages, and a few diodes to step down that voltage for the LCD screen.

As you can see in the clip after the break, alligator leads can be used to connect the test circuit to the inputs (don’t forget the ground reference!). Thee buttons at the bottom let you navigate the captured data by panning and zooming. Perhaps the best design feature is the single-sided circuit board which should be quite easy to reproduce at home.

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Using A Touch Screen With An STM32 Microcontroller

January 10, 2012 by Mike Szczys 10 Comments

[Andy Brown] has been working on a series of tutorials revolving around the STM32 processor family. He’s using the STM32plus development board, with an STM32F1 ARM Cortex M3 processor to drive a couple of different full color graphic LCD screens. His latest installment shows how to read from the touch screen included with both displays.

After the break we’ve embedded the video from which this screenshot was taken. As an example, [Andy] has programmed a painting program to show off what the touchscreen overlay is capable of. It starts off with the calibration routine we’re all familiar with, then drops to this screen with a virtual control panel and blank canvas.

This hardware uses the Texas Instruments ADS7843 controller, which [Andy] says is extremely common and that several other manufacturers use the same communications protocols. He discusses how to communicate with the controller, and how to incorporate the data into your program. Included is an open source library which you can use in your own projects.

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Combine 2 Non-Working Sony TVs Into One That Works

December 7, 2011 by Jeremy Cook 16 Comments

Have you ever wondered if you could fix your two broken LCD TVs by combining them? Neither had we, but [Redion] did, and the answer is yes, it can be done. Although it may sound like a serious kludge, the finished product actually looks quite nice from the view provided. On the other hand, we don’t know how the internals will hold up, but it apparently works well now.

For this hack, the working internals from a 32 inch Sony LCD TV with a broken display were combined with a 40 inch Sony LCD TV that had an undamaged display but fried internals. Although this would most likely not work for every TV out there, it’s still a pretty neat experiment. Many people would simply assume something like this would not work, and trash both TVs. We would suggest the new TV be named “Nomad”, just avoid wearing a red shirt around it.

Keep in mind with any TV hack, taking one apart can expose you to large capacitors that may or may not be charged and can be quite dangerous (they can stay charged for a long time). We don’t necessarily recommend duplicating anything here, but use extreme caution if attempting anything like this.

Network Monitoring Panel Built From The IT Department Junk Heap

November 30, 2011 by Mike Nathan 11 Comments

network-monitoring-panel

One of the benefits of working in IT is that there is typically a healthy supply of miscellaneous, half-functioning equipment to mess around with. [Vittore] had an old laptop with a busted LCD sitting around (Google Translation), so he figured he might as well get it to do something useful. With a spare desktop LCD panel and some software tweaking, he built himself a slick network monitoring panel that hangs in his office.

He stripped the laptop down to the bare essentials, and mounted it along with an LCD screen in a plexiglass enclosure. He has Nagios running a server in his office, and with the help of a few plugins, he created a simple web interface that show him the topology of his entire network. The panel itself runs a live version of Debian, which he configured to load up his Nagios web page each time it is started.

While having the ability to view the status of every network-connected device in an instant is great, he didn’t stop there. While browsing around online, he found diagram for a simple USB-based performance monitor that uses a PIC to drive a pair of VU meters. He hooked the meters up to a router monitored by Nagios, so he can watch office’s bandwidth usage in real time.

If you’re interested in seeing how it was built, be sure to check out the Flickr photo set put together by [Vittore’s] co-worker [Matthew].