Serial port JTAG programmer

If you’re planning to do some hacking with CPLD or FPGA chips you’ll need a way to program them. JTAG is one of the options and here’s a cheap method that uses the serial port (translated).

This method requires only four signals (TDI, TMS, TCK and TDO) plus ground. But the problem is that an RS232 serial port operates with 12V logic levels and the JTAG side of the programmer needs to operate with the logic levels native to the device you’re programming. Commercial programmers use a level convert IC to take care of this for you, but that doesn’t mesh with the cheap goal of this project. Instead, [Nicholas] uses Zener diodes and voltage dividers to make the conversion. There is also an LED for each data signal to give some feedback if you’re having trouble.

You can use this along with a programming application that [Nicholas] whipped up using Visual Studio. It works well via the serial port, but he did try programming with a USB-to-Serial dongle. He found that this method slows the process down to an unbearable 5-minutes. Take a look, maybe you can help to get that sloth-like programming up to a manageable speed.

[Thanks Alex]

It’s like… I can tell the time just by the color, man

[Alex] has reduced the resolution of his timepiece as a trade-off for speedy-readability. At least that’s what he claims when describing his color-changing clock. It uses a ShiftBrite to slowly alter the hue of the clock based on the current time. The concept is interesting: 12:00 starts off at white and slowly fades to green at 3:00, blue at 6:00, red at 9:00, and back to white by 12:00 to start the process over again. He has gotten to the point where he can get the time within about 15 minutes just with a quick look. But he did need to spend a few days acquiring the skill by having the color clock sit next to a traditional digital clock.

The build is pretty simple and we’d bet you already have what you need to make your own. [Alex] is really just proving a concept by using the ShiftBrite and an mBed, there’s no precision RTC involved here. So grab your microcontroller of choice, and an RGB LED of your own and see if you can’t recreate his build.

Of course you could always choose to build a color-based timepiece that’s even harder to read.

BAMF2011: Lasersaur is one BIG laser cutter!

Psst…wanna buy a laser cutter, but not ready to sell your internal organs? Nortd Labs’ Lasersaur project aims to create an open source large-format laser cutter/engraver that undercuts (har har!) the cost of commercial models by an order of magnitude.

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Hacking for feline enjoyment

[Dino] is staying true to his goal of hacking one project every week. This time around, he’s working on a toy that will amuse and delight his cats. The project centers around a mouse house that has two holes where mice can stick their heads out. When they do, a little LED lamp illuminates their appearance in hopes to catch the eye of your lazy kitty.

The mechanism that automates this device is quite clever and reminds us of the most useless machine. That is, the armature that holds a mouse on either end actuates a limiting switch in the middle of the box when it moves to expose one of the mice. Each of those mice is attached with a rod, along side a leaf switch that makes the mouse retreat when boinked on the head by the cat.

It only takes [Dino] about six minutes to walk us through the build in the video after the break. What follows is a walk through of the wiring and some playtime with the family pets. Despite the intended purpose, it looks like the dog is much more interested than the cat. Either way, it’s a winner in our book.

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Shoehorning RS-232 into a Minitel terminal

In the early 80s, millions of terminals were handed out to French telephone subscribers. Nearly 9 million of these Minitel dumb terminals were in use at one time, and with that degree of ubiquity, we’re surprised we haven’t heard of them before. These boxes were usually connected to the outside world through their internal 1200bps modem, but [O. Blt] came up with this build (Google Translate link) so he could connect to a local machine with an RS-232 port.

After digging up the pinout for the Minitel’s DIN-8 port, [O. Blt] designed a little board around a MAX232 chip scavenged from an old motherboard. Of course there was a need to get the terminal to do something, so [O. Blt] used the Minitel as a display and remote control for Winamp. The project was successful, but not very useful – at 1200 bps, the refresh is very, very slow.

American readers may remember connecting to the Minitel network with their Apple ][s and C64s with CommunityLink, but this service was driven out of the market by the giants of pre-web dial-up, Prodigy and Compuserve. In any case, after seeing the AZERTY and alphabetic keyboard layouts of these old boxes gives us a feeling of nostalgia for a time before everything dealing with computers was standardized.

We know “Mario’s Early Years” was a let down, but this takes it a bit too far.

[JJ Hendricks] wrote in to tell us about his SNES cartridge urinal. The fully functional urinal is constructed with 40 SNES cartridges and sealed up with polyurethane. The base of the whole operation is actually not a puddle of festering urine, but instead poured polyurethane that ensures proper flow through the drain. You heard right, this urinal actually flushes! As a bit of consolation [Hendricks] plainly states in the directions:No good games were damaged in the making of this video. All the video games used in this urinal were already broken or worthless sports games”. We have featured some SNES cartridge readers before, so now you have something to do with all the leftover hardware! Gross.

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