Fail Of The Week: Reset Issues With 595 And HD44780

February 27, 2014 by Mike Szczys 36 Comments

fotw-reset-issues-595-character-lcd

We really like to see hardware hackers stepping out of the safe and polished boundaries of available Arduino libraries. One example of this is a project which [Matteo] thought worked: using a shift register to drive a character LCD. This can be a desirable way to do things, because it takes the GPIO usage down from six to just three connections. If you don’t remember seeing that one earlier this month take another look. The gist of it is that [Matteo] hacked one function in the LiquidCrystal library to make it happen.

What makes this a truly great fail is that the problem was not immediately apparent, and is difficult to reliably reproduce. The LCD is unstable depending on how the Arduino board is reset. When connecting the Arduino to a computer the screen doesn’t work until you press the reset button. But press the reset button repeatedly and you get a non-functional screen plus the gibberish seen above.

There’s not much to go on here, but we think it’ll be a lot of fun to state your theory on the malfunction and suggesting for testing/fixing the issue. This could be a lot of things, the controller on the display getting mixed-up, the 595 missing an edge (or something along those lines). Do you fix this with hardware (ie: capacitor to avoid voltage dip), a software issue (need a longer delay after startup), or a combination of the two?

Fail of the Week is a Hackaday column which runs every Wednesday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Mini Go Kart Built In A Day

February 27, 2014 by Brian Benchoff 19 Comments

kart

The crew at the MIT student-run shop MITERS love their go karts, and when sitting around a pile of parts in the middle of the night on Saturday, there was only one thing to do: build a mini electric go kart in a day.

The parts for this were all taken from the jumble of parts lying around the shop: a few scooter wheels, some aluminum tubing, a 1×4″ piece of extrusion, a huge motor, and a ton of A123 cells were enough to ge tthe project started. They began by bolting the back wheel and motor to the aluminum extrusion and machining a simple steering mechanism.

The real fun began when they realized they could fill the aluminum extrusion with batteries, creating a 6S5P pack with the balance connectors and – after a few tries – the proper insulation. Combine all the parts with a Kelly motor controller and an old Brooks saddle, and the MITERS have a fairly light mini go kart that can cruise around the halls at about 15mph. Not much, but it was built in a single sleep-deprived night.

Video of the kart in action below.

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Taste-O-Vision Is Now A Thing

February 27, 2014 by Brian Benchoff 26 Comments

taste

Not satisfied with late 1950s concepts of Smell-O-Vision [Nimesha] has created something extraordinary: A digital taste sensor, capable of representing taste with a little bit of heat, electricity, and an Arduino

The device purportedly works by via thermal and electrical stimulation of the tongue using silver electrodes. According to this video, different tastes are created with different currents and temperatures. For example, a sour taste is produced on the electrodes by varying the current from 60uA to 180uA and increasing the temperature up to 30 degrees C. Mint is produced by simply decreasing the temperature from 22C to 19C.

The control electronics include an Arduino, a motor controller, and a heat sink attached to one of the silver electrodes. Communication is done through USB, and of course there’s a mobile app for it, more specifically a protocol called Taste Over IP. This allows anyone to send a taste to anyone with one of these devices.

Videos below, and before you laugh, we’d really like to try one of these out.

Thanks [Jess] for the tip.

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RFID Keepsake Box Is Sweet And Secure

February 27, 2014 by James Hobson 17 Comments

box-tag-top

[Mike Buss] wanted to make his girlfriend something unique for her upcoming birthday — she had mentioned she wanted something to keep small mementos in, but [Mike] decided to step it up a notch on the awesomeness scale.

You see, a few years ago [Mike] read about the Reverse Geocache Puzzle by [Mikal Hart], which is an awesome box that gives you feedback as to how far away you are from the “secret” location that the box will open at — To raise the stakes however, if you ask for the distance more than 20 times it locks itself forever! Now, unfortunately, a memento box wouldn’t be very useful if you had to go to a secret place every time you wanted to open it… so [Mike] decided to secure it another way, using RFID!

It makes use of an Arduino, a Parallax RFID Reader, a micro servo, a button, an RGB LED, and a cleverly designed latch made of a metal eye hook and small copper rod. Since the box is battery powered, [Mike] has added an extremely clever fail safe mechanism. The 9V battery inside includes two extra contacts to the outside of the box via small screws. Completely inconspicuous, but if the battery is dead, simply hold a new 9V to the screws with the RFID card in place, and bam, the box opens!

We’re pretty sure she’s going to like it — check it out after the break!

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Giant Tetris Adds Some Retro To Your Room

February 26, 2014 by James Hobson 15 Comments

giant tetris

[Sam] just finished off this awesome 6 foot tall Tetris game using National Instruments myRIO with FPGA.

The build makes use of a 10 x 20 grid of RGB LEDs controlled by the myRIO. It’s played by using a web interface on any device, as long as you have WebSockets support. [Sam] had originally built it using an Arduino at the heart, but wanted a stand-alone device to do everything — no extra computer or Raspberry Pi for the web interface. That’s when he discovered the myRIO — it’s a pretty cool piece of hardware that we haven’t seen too much of yet, other than the recent Picasso with a Paintball gun project…

Don’t forget to watch the following video to see the game in action!

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Twitch Plays Pokémon: Better Than Prime Time TV

February 26, 2014 by Adam Fabio 27 Comments

What do you get when you put together a classic Game Boy game, some glue code, a streaming video website and 1 internet? Twitch Plays Pokémon (TPP), a social experiment where thousands of people “cooperatively” play a game of Pokémon Red/Blue. TPP was created by an anonymous Australian programmer who enjoyed the SaltyBet interactive channel on twitch.tv. Rather than use SaltyBet’s method of having users interact via an external website, [TPP’s creator] decided to use twitch’s own IRC based chat servers. Starting with VisualBoyAdvance, a popular C/C++ based Game Boy emulator, [TPP’s creator] began building the system. [TPP’s creator] went with python to create the web-to-emulator interface. A JavaScript app displays the live moves on the right side of the screen.

Gameplay is simple – users type their command (Up, Down, A, B) into their IRC or web client. In the original configuration, commands were processed in the order they arrived at the game. The system worked until the whole thing went viral. With thousands of people entering commands at any given time, poor “RED” would often be found spinning in place, or doing other odd things. The effect is so compelling that even [Randal Munroe] has written an XKCD entry about it. To help the players get through some of the tricky parts of the game, [TPP’s creator] added a game mode selection. Users can play in “Democracy” where the system takes votes for several seconds, then issues the highest voted command. The original anything goes game mode was renamed “Anarchy”. Switching from one mode to the other is determined by the users themselves in real-time.

[Devon], one of our readers, has been busy as well. He’s written up a tutorial on turning a Raspberry Pi into a dedicated TPP viewer. We’d love to see a TPP battlestation – a Game Boy modified to display TPP, as well as send commands to the IRC servers when buttons are pressed. Who will be the first reader to knock that hack out?

Hackaday 68k: Enclosure, Backplane, And Power

February 26, 2014 by Brian Benchoff 46 Comments

It’s about time for an update for Hackaday’s latest project – a modern retrocomputer based on the Motorola 68000 CPU. In this update, we’ll be taking a look at the enclosure, the backplane itself, and how we’re going to power this thing.

This is only an update to the project; you can check out the current status over on Hackaday Projects. It’s Hackaday’s new collaborative project hosting site where you (and your friends) can design, build, or document anything you have in mind. Request an invite for the alpha release of Hackaday Projects and you can give this project a skull! Seriously, this project is only the third ‘most skulled’ one on Hackaday Projects.

Now that the completely transparent pitch for Hackaday Projects is over with, we can get on to the update for the Hackaday 68k. Click that ‘Read More…’ link.

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