Fattening A Thin Client To Run A Debian Desktop

October 24, 2011 by Mike Szczys 13 Comments

While watching his thin client boot up [Nav] noticed that it’s using some type of Linux kernel. He wondered if it were possible to run a full-blow desktop distribution on the device. A little poking around he got a Debian desktop distribution running on a thin client.

The hardware he’s working with is an HP t5325. It’s meant to be a dumb client, connecting to a backend machine like a Windows Terminal Server or via SSH. But it’s got a 1.2 GHz ARM processor and [Nav’s] preliminary investigations revealed the it’s running a version of Debian for ARM. He used CTRL-C during the boot sequence to derail that process and dump him to a shell. The login was easy enough to guess as the username and password are both ‘root’.

Once he’s got that root access it was slash and burn time. He got rid of the HP-specific setup and made way for additional Debian modules like the apt system. This isn’t trivial, but he’s worked out a bunch of sticking points which makes the process easier. With the repository tools loaded you can install Xserver and Gnome for a full-blown desktop on the embedded hardware.

Using An LCD’s Poor Viewing Angle To Your Advantage

October 24, 2011 by Mike Szczys 17 Comments

Early LCD monitors had some pretty awful issues when not viewed from directly in front of the screen. These days the technology has really minimized this flaw, but if you still have a cheap monitor on hand you might want to pull it out and give this hack a try. [Chris Harrison] is using oblique viewing angles to display additional information on cheap montiors.

Take a look at the two images above. The one on the left is taken from directly in front of the monitor and looks normal. But if you view the same screen from the side, the financial information is obscured. This is by design. Using very light colors, the obscuring characters are almost indiscernible from straight on, but you can just see them there a little bit (they look like burn-in does on a CRT screen). But from the side, these light colors become quite bold and blend with the rest of the data on the screen.

This works because of the polarizing filters on an LCD screen. You might want to watch [Bill Hammack] explain how an LCD works if you’re not familiar. Because the viewing angle color changes are a flaw and not a feature, manufacturers make the up-and-down angles the worst to improve on side-to-side viewing. [Chris’] experiments play into that by using a computer monitor on its side. Check out the video after the break to see some of the different applications that he uses this for.

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Logging Bubble Frequency And Pressure In Your Fermenter

October 24, 2011 by Mike Szczys 21 Comments

In an attempt to add technology to his brewing process [hpux735] build a sensor rig that monitors bubbles and pressure during fermentation. What does this have to do with brewing great beer? We’re not sure and neither is [hpux735], but he’s got some preliminary readings to spark your imagination.

The bubble sensor itself was inspired by a SparkFun Tutorial where fermenting wine was monitored with a data logger. It uses an optical gate to detect the passage of air. But the goal here was to combine bubble frequency with internal pressure measurements to calculate how much CO2 is being vented. Perhaps it would be possible to get an idea of how close the batch is to completion based on those calculations. A hole was drilled into the fermenter side of an airlock to take these pressure readings.

This actually works quite well during secondary fermentation when the bubble frequency is quite slow. The hardware is able to discern a pressure difference before and after a bubble has passed the lock. Unfortunately the system breaks down during the vigorous bubbling that takes place soon after pitching yeast. See a few bubble-counting clips in the video after the break.

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Adding A Compact Flash Reader To A Korg Triton

October 23, 2011 by Mike Szczys 22 Comments

[Roberto Barrios] has a Korg Triton sampling keyboard which he enjoys very much, but has grown tired of using media of yesteryear to store his work. He had the option of floppy disk or Jazz drive and for a time he was using a floppy-to-USB emulator, but the keyboard still insisted on a 1.44 Mb storage limit using that method. He decided to crack open the case and add his own CF reader.

It should be noted that this hack could have been avoided by using the 25-pin connector on the back of the keyboard. He didn’t want to have external hardware, which is understandable if you’re gigging–it’s just more equipment to keep track of. His solution uses the floppy disk drive opening to mount the card reader. His electrical connections are made with a ribbon cable. He cut off one end, and soldered the individual wires to the contacts on the motherboard. The reader is seen as a SCSI drive by the Korg firmware thanks to a SCSI-to-IDE adapter, so the storage limitation is based quite fittingly on the size of the CF card used.

Look at that cable management. You’d think it came straight from the factory like this!

Snooping Around In The Iclicker Hardware And Firmware

October 23, 2011 by Mike Szczys 26 Comments

[Arko] was compelled to purchase an iclicker to use in some of his college courses. It’s similar in size to a television remote control except it only has six buttons and it communicates via radio frequency instead of infrared light. The idea is that classrooms have a base station that the instructor uses, and he or she can ask questions of the class and have instant feedback. Results are often projected on a screen for all to see but only the instructor can get at the breakdown of who answered in what way. In [Arko’s] case, the class awards participation points that you can only get by using this device. He decided to actually learn something from the expenditure by reverse engineering the device.

Preliminary hardware inspection told him that it uses an ATmega8 microcontroller and there’s a standard 6-pin ISP footprint just waiting to be populated with a surface mount pin header. Once he soldered on that header, he tried to read out the firmware but the iClicker reset itself. He guessed that there was something going on with the power and ground lines so he soldered directly to them and was able to dump the data–the security fuses are not set. He goes on to snoop in the EEPROM to find where the device ID is stored, and then to watch some of the SPI communications to see what the microcontroller is sending to the radio chip. But there’s a lot left to discover and he’s planning at least two follow-up post to share what he finds.

Just looking to repair your dead device? Check out this tip on battery problems with the iclicker.

Hacking In Cameroon For Profit And Entertainment

October 22, 2011 by Mike Szczys 24 Comments

[Bill Zimmerman] is in Cameroon and has been posting some really interesting articles about life in the central African nation. It comes as no surprise that imported goods can be prohibitively expensive for many of the country’s residents, so building tools and goods is way to improve life and save money. The image above is a metalworking cooperative where any number of products are manufactured from recycled materials, often using tools that the craftsmen made themselves. Their wares are amazingly wide-ranging; crow bars, motorcycle seats, buckets, plows, hammers, knives, cold chisels, and much more. The video after the break shows the tradesmen hard at work. See some video of the cooperative after the break.

But adults aren’t the only ones getting in on the action. Remember [William Kamkwamba] who built a wind generator for his villiage? It seems the tinkering spirit runs deep in the children of Cameroon as well. [Bill] came across some kids who grabbed leftovers like the soles of sandals, scraps of rope, and empty sardine tins to build a steerable toy car.

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7400 Drum Machine Is A Delight

October 22, 2011 by Mike Szczys 24 Comments

[74hc595] just finished his entry in the 7400 logic contest. It’s a drum machine built entirely from 7400-series logic chips. He hasn’t quite reached full completion of the project yet. The hardware works just fine, and he’s built a foam core face plate with many more controls than you see here but much of the circuit is still on a breadboard at this point and only two of the channels have been complete thus far.

Jump to the video clip after the break to get the details of how the system works and to hear it in action. This demonstration is one of the best we’ve seen for a synthesizer project as he actually talks about what each control does, and how that is accomplished with the hardware. We’re not going to go into detail about the circuitry he’s designed. As we said before, it uses 7400 logic but also sources a 555 timer to keep the beat. The page linked above has a PDF of the schematic available and you could really lose a lot of time studying how he did this. We might even try to build it in a simulator to see what we can learn.

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