Apple II Weather Display (part 1)

April 18, 2011 by Kevin Dady 24 Comments

Due to computer issues I had to rob some parts from my “electronics” computer, which wasn’t bad, since I was not working on anything at the time and I felt a software project itch. I also wanted to do something with my Apple //c, which resides on my computer desk, so this ghetto brute force “solution” to use the 25 year old computer as a weather display came about.

In a nutshell there is the Apple II, a serial cable, and a PC running linux mint 10 and a handful of command line utilities. My specific Apple is the fist revision of the //c which means its got a buggy rom and the serial port(s) can be troublesome, the best speed I was able to get was 600 baud with just basic, though every other model could probably go a little faster.

On the linux side, wget downloads html and the radar image from Weather Underground’s mobile site, which is not a perfect source, but its easy. A lua script phrases text and graphics into string patterns that the Apple II can handle as keyboard input, and its sent down a serial cable where it is drawn on screen in basic.

Yea its pretty darn slow … it typically takes about eight to twelve minutes to redraw the screen, which is not all that horrid (imo) considering what is going on, but anyone with a more serious take on this could find numerous ways to optimize it, I just wanted to see what it would look like.

Join us after the break for a short video and to read all the details about how this all works!

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Play Unreleased Retro Games On The Real Thing

April 12, 2011 by Kevin Dady 17 Comments

Star Fox, one of the greatest 3D space shooters ever developed, has a pretty decent fan base even after eighteen or so years. It had a sequel that was 99% complete, but it came very late in the Super Nintendo’s life and it was held off so that the next great Star Fox would be on the newest Nintendo console, the N64.

You could get the Japanese version, which aside from a couple debug routines, is complete, and you could play it on an emulator. While emulators are fine for most of us, anyone who has played a game on the real metal can quickly and easily pick out minor nuances.

Since playing Star Fox 2 on the real hardware is not a simple trip to the flea market, [Doug] went about ripping apart an old SNES cart and placing a eprom inside with the data from the game. Through that 8 page forum post you can see the project start, progress through different constructions, and result in 3 fully working carts, complete with custom labels.

Join us after the break for a quick video.

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Hacking Electronic Price Tags

April 7, 2011 by Kevin Dady 66 Comments

Something new is coming to a store near you: electronic price tags. [deadbird] decided to get one and see what makes it tick. First off it just looks like an LCD with some coin batteries and a simple board, but removing the batteries it was found that the text still appeared on the screen meaning its an E-Ink display.

Close examination of the chips on board shows that this model has an ATMEL ATMEGA16L, and a ATMEL952 25128AN (a 128k eprom with SPI interface), which makes this thing possible to bend to ones will. Also, dumping the eprom with an Arduino gets everyone a bit closer to decoding the instructions this thing needs to display its graphics, similar to the HP VFD hack we posted about not too long ago.

We have not seen these yet in our local shops, but give it time and it is bound to start popping up in our favorite surplus locations soon enough.

Super VMW CPU Meter

April 7, 2011 by Kevin Dady 10 Comments

After many delays, restarts, and years, [Vince ] has finally finished his Super VMW CPU Meter. Featuring six alphanumeric red led displays, two 10 segment bar graphs, twelve red LEDs, and six color LEDs its got plenty of “screen” space to show all sorts of useful information.

Electrically its driven by four SAA1064 LED driver chips attached to an i2c bus which is banged by a PC’s parallel port and driven by software in linux. The software allows you to build displays for what ever application you may want, and even includes a color ASCII output so you can see what it will look like before you even have hardware.

Four examples are given, one is a cpu meter which uses the bar graph displays to show load per core. Another uses the bar graphs as a VU meter for your music while displaying the song’s information. There is a clock in all the normal formats + UNIX time, and some scrolling text demos.

Construction gets a little odd as overhang of chips and connectors was not really taken into account so some “lofting” was needed to raise the trouble spots above the rest of the board. It is not something we would want to do, but a handy trick if we are ever faced with that situation.

Join us after the break to see this wild light show in action. Continue reading “Super VMW CPU Meter” →

Everything You Need To Know About Wall Warts

April 6, 2011 by Kevin Dady 25 Comments

If you work with electronics at any skill level you need juice. [Jon] has a great, and clearly worded tutorial about Wall Wart Power Supplies with pretty much everything you need to know about those little black boxes hanging off of your outlets.

The whole thing starts off with the basics like transformers, rectification smoothing and regulation, then moves on to the different basic types, dedicating a page to linear, regulated and switching types, giving output performance charts under different situations.

Also included is a run-down of DC barrel jack structure so you get the right plug every time, wall wart type identification, a random sample comparison test, and a good selection of formulas to even keep the old hats reading along. Although you might want to set aside a little time at 9 pages and some Q/A in the comments, it might take a moment to read.

Atmega Analog Two Pack

April 5, 2011 by Kevin Dady 7 Comments

Back in February, [ProtoStack] posted a pretty good tutorial on how to do Analogue to Digital Conversion on an Atmega168. Based on a bread board, the tutorial also shows the often forgotten low pass filter on the AVCC lines to ensure an extra stable reference and an analog input connection to a simple voltage divider as a study point.

Moving on into the micro controller, the registers you’re going to need to twiddle are laid out and explained in detail. Finally you’re shown how to put it all together in a software project that outputs the analog reading onto a standard character LCD.

But hold on! There is more. Just released is a follow up to that tutorial which adds on Analogue to Digital Conversion Interrupts on an Atmega168A. So if you’re sitting there looking at an Arduino and want to know more about what’s going on under the hood, these are a good place to start.

Redeye Printer Interface

April 5, 2011 by Kevin Dady 6 Comments

This handy printer interface started out as a request on our very own forums when forum member [victorf] needed some output via thermal printers. He had scored a number of HP82240B thermal printers intended for use with HP calculators, but of course they used the somewhat arcane HP protocol first drafted in the 1960’s and needed some help.

Fellow forum member [wireb] started to look into it, found out it uses a standard 32KHz carrier signal, and started asking questions about its use. Grabbing a pdf of the manual he was able to find out all the details to what the printer was expecting in the form of communications.

After a few weeks, [wireb] was able to make a convenient, logic level serial to HP-IR adapter based around a PIC16F1824 who’s firmware supports 9600 8N1 or 2400 8N1 speeds, ASCII text, and the printer’s “advanced” graphical modes via escape sequences.

If you have not checked out our forums yet we suggest you do!