FPGA Makes ASCII Video

Human beings like pictures which is probably why there’s the old adage “A picture’s worth a thousand words.” We take computer graphic output for granted now, but even in the earliest days for Teletypes and line printers, there was artwork made from characters ranging from Snoopy to Spock. [Wenting Z] continues the tradition by creating an FPGA that converts VGA video to ASCII art and outputs it via DVI.

The device uses a Xilinx Virtex device and uses about 500 LUT (look up tables) which is not much at all. You can see a video (that includes an overlay of the source video) of the device in action below.

In fact, we think of art like this as a computer phenomenon, but [Flora Stacey] created a butterfly on a typewriter in 1898 and ham radio operators were doing art using paper tape for the last half of the twentieth century. Even before that, In 1865, Alice in Wonderland had a certain passage that was typeset to suggest a mouse’s tail. Perhaps the pinnacle is the famous ASCII version of Star Wars.

This is decidedly less mechanical than some of the other ASCII art projects we’ve seen. If you have a taste for more text art, have a look at some other examples, including a very old advertisement that uses character art.

Continue reading “FPGA Makes ASCII Video”

Raspberry Pi housed inside a computer monitor


Behold, something we’ve always wanted. [Matthieu] mounted his Raspberry Pi board inside of a computer monitor. His work makes for the cheapest smart-TV modification we can possibly think of.

The image above shows the monitor’s driver board on the left, with the Raspberry Pi mounted on the back plastic cover. [Matthieu] used a short HDMI cable to connect the two. The HDMI connector plugs into the RPi directly. The other end has been cut off and the wires soldered to the DVI pins on the monitor’s PCB. This is not a problem since HDMI and DVI use electrically identical protocols. The one thing missing is audio. But if you were pulling off the same hack with a device that had HDMI (like a television) it would just be a matter of also soldering in the audio connections. While he had his iron hot he also connected a 5V source from the monitor board to the RPi. He completes his hack by cutting a slot in the monitor case to allow access to the SD card.

We’ve long wanted an XBMC computer we could velcro to the back of the TV and the RPi turned out to be just the thing. Now we’ve got to consider cracking open the TV to replicate this internalization hack!

Moving an FPGA Project from VGA to DVI-D

It’s fairly easy to create VGA with an FPGA using a simple R/2R DAC. As [Mike] points out, this requires a lot of IO pins, and many development boards only support 8 bit VGA. Analog VGA is being replaced with DVI-D and HDMI on many devices nowadays, so it would be nice to port projects from VGA to DVI-D.

To address this, he’s come up with a simple DVI-D implementation in VHDL. The result converts RGB and sync data for VGA into DIV-D. Since DVI-D and HDMI both use the same signals for video, this can be connected to either input on a monitor or TV.

This implementation is shown displaying a test pattern on the Pipistrello development board, which features a Spartan 6 LX45 FPGA, but the project was written to be portable to other vendor’s FPGAs. With the right connector and a fast enough clock speed, this project should help move a project from 8 bit VGA to glorious 32 bit color.

Tricking the BeagleBone into outputting video

[FlorianH] wanted to get video out working with his BeagleBone but he just couldn’t figure out how to make the kernel play ball. Then a bit of inspiration struck. He knew that if you plug in the official DVI cape (that’s the BeagleBone word for what you may know as a shield) the kernel automatically starts pumping out the signals he needs. So he figured out a way to spoof the cape and output video.

At boot time the kernel polls the I2C bus to see what’s connected. The DVI cape has an EEPROM which identifies it. Since the data from the EEPROM is available for download [FlorianH] grabbed the data he needed, then used an ATmega32 to stand in for the memory chip. When he got the chip talking to the BeagleBone he was able to detect the video sync signals on his scope and he knew he was in business.

Look closely at the breadboard on the right. We love that SIL breakout board for the ATmega32. Very prototype friendly!

Apple Studio Display connector ports

[Warrior_Rocker] pulled off his own Apple Studio Display hack by removing the cable and adding ports. As we saw in Wednesday’s post, these displays use a cable with a proprietary connector that combines DVI, USB and Power. Instead of altering the cable, [Warrior_Rocker] removed it completely. By wiring up a standard barrel jack for power, a USB type-B socket, and a DVI port, he can now use standard video, power, and USB cables to connect to the monitor.

This project was actually submitted to us on May 25th and we missed it. It’s sad that sometimes tips fall through the cracks, and we’re sorry that we missed this particularly well-executed hack. [Warrior_Rocker] wrote in asking why his project didn’t qualify after seeing the similar post on Wednesday. So please don’t take it personally if your project doesn’t get posted. If you think it fits right in here at Hackaday and haven’t heard anything after two weeks or so, consider sending to us again.

Normal connectors for Apple Studio Display

[Sherry Wu] sent in a link to her Apple Studio Display hack. She got her hands on the 17″ display which has a proprietary Apple Display Connector that rolls signals for DVI, USB, and 25V power into one plug. Convenient right? Not if you want to use it on a machine that has standard video connections. No problem, she got out her meter and figured out which wires belong to each signal. After some soldering she now has a DVI connector for the video, and a 24V bench supply is standing in for power until a dedicated unit arrives. No luck so far at getting the USB and hotplug detection to work but she plans to keep going until that’s accomplished.

Looks like you can pick these displays up refurbished for as low as $75. Might not be a bad addition to your home setup if you’re willing to do some soldering.