A Visually Satisfying Tape Ticker

August 20, 2012 by 8 Comments

This visually stunning tape ticker prints out [Horatius Steam’s] emails for him. It watches his email address for a secret trigger phrase in the subject line. Sure, thermal receipt printer projects are becoming rather common, but we can’t remember seeing one that took this much time and effort to make it into a showpiece.

The two parts that make this happen are the thermal printer with cutter module and the glass dome which is just large enough to house the business end of it. The driver PCB for the printer is hidden in the base (a paper tube which is painted to took like wood), which positions the outfeed near the bottom of the dome. This had the added benefit of leaving plenty of room for [Horatius] to proudly display the paper roll. Since the receipt printer is designed to work with a Windows machine there was no custom circuitry necessary.

High Voltage ROV Adventures

August 20, 2012 by 19 Comments

[Eirik] wrote in to share the build log for the third iteration of his underwater ROV. The first two project were completed and tested (you may remember reading about it back in January), but both had issues that caused general failure. Most notably, the introduction of water where he didn’t want it. But this time around he seems to have gotten everything right, successfully taking this little guy down to twenty meters without a leak.

One of the problems he had on version two was supplying electricity from the surface. He needs 12V at up to 10A, and had to use a tether made of 14 AWG to make it happen. That’s a lot of heavy wire to be hauling around and it made the ROV virtually unable to move itself. He wanted to go back to using Cat5e cable but it won’t handle that kind of current. He ended up using an inverter at the surface to up the voltage to 130V, and a switch mode supply on the ROV to get back to 12V. This caused noise on the data lines which he fixed by adding a full-wave rectifer to the inverter’s output.

The dive video after the break shows off the crystal-clear camera shots this thing can capture.

Continue reading “High Voltage ROV Adventures” →

Summer Vacation Home For The Indoor Cats

August 20, 2012 by No comments

Throw your indoor cat a bone (or a tuna steak as it were) this year by building them a summer vacation spot. Since [Travis Brown] lives on a busy street he worries that his cat would get hit by a car if allowed to roam outside. He and a friend found a suitable alternative with this outdoor cat enclosure.

The centerpiece of the build is a platform that overlooks the back yard. It’s got a couple of different levels which lets the cat see over the deck railing, and provides a bit of shade from the sun during the day. Chicken wire encloses the entire structure to make sure our feline friends don’t go off on their own, but the gang-plank that connects the platform to the house lets them decide when to go outside or come back in. The entrance to the house is an open window covered with plywood and fitted with a cat door. This is a nice touch since the cat door can be locked to keep them in a night.

Between this for summer and the heated bed for winter you’re going to have the most spoiled cat on the block.

Raspberry Pi As An AVR Programmer

August 20, 2012 by 23 Comments

AVR programmers can be bought for just a few dollars on the Internet, but if you’re building an expansion board with an AVR for your Raspi, this is the build for you. It’s a safe way of programming an AVR via the Raspi’s GPIO pins that uses an extremely minimal circuit.

The AVR ISP interface looks a lot like an SPI interface, and the easiest way to program an AVR with a Raspi would be to bitbang all the commands from the GPIO pins. Sometimes, though, the logic of the AVR and Raspi would be at different levels, so while bitbanging may work in a pinch it’s not something anyone should use regularly.

To get the Raspi and AVR talking to each other safely, [Steve] built a small circuit from a 74244 buffer and a FET. With the added support for Linux GPIO avrdude programming, it’s a snap to program an AVR with a Raspi.

A few days ago we ran across a hugely overwrought PIC programmer for the Raspi, so we’re glad to see another round in the PIC/AVR holy war go to the AVR camp.

Thanks [Mateusz] for sending this one in.

Rendering OpenSCAD In The Browser

August 20, 2012 by 13 Comments

If you haven’t heard of it, OpenSCAD is a really wonderful tool for 3D modeling.  While it doesn’t have the traditional graphical interface of AutoCAD – it’s basically a programming language for 3D models – OpenSCAD is able to create very complex parts with only a few lines of code.

That’s all well and good, but what if you wanted to edit OpenSCAD parts in your browser? Enter OpenJsCAD, an OpenSCAD interpreter written entirely in Javascript and able to be embedded in a web page.

OpenSCAD allows for two types of modeling – constructive solid geometry, or taking 3D primitives and stretching, scaling, and intersecting them to create a 3D shape, or extrusion from a 2D outline. Quite a few RepRap parts were designed in OpenSCAD, and the lightweight interface and open source nature means it’s perfect for designing stuff to print on your Makerbot.

Tip ‘o the hat to [Gordon] for sending this one in, and we really have to commend him for writing his own online scriptable CAD exporter before finding out about OpenJsCAD. He may be a little late to the online OpenSCAD party, but we have to agree with him that an online 3D solid editor would be an awesome feature for Thingiverse to roll out.

New And Improved Old Hackaday Store!

August 20, 2012 by 20 Comments

I am going to start off by saying our zazzle store was pretty sad. The prices were just way too high. I put that store into place because frankly, the one I was running was a pain in the butt.

The good news is that I’ve got a new system in place. It is bright and shiny and looks much easier to use. Not only that, but since we’re not using someone like zazzle, we’re keeping the cost down! Or standard shirts are $18. We have stickers too, and this time, we have both standard stickers as well as the custom cut vinyl decals everyone loved before.

Several products have not yet arrived. Since this is the grand opening and I feel a little bad about how expensive the zazzle store was, I’m running a special. $16 for shirts if they’re ordered before August 31st. 

I’m talking to other people about offering some products besides shirts and stickers in the store. Stay tuned to see what we’ve got going on!

Reliving The BBS Days With A Propeller

August 20, 2012 by 17 Comments

Back before the world wide web, self-proclaimed geeks would get our compute on by dialing in to bulletin board systems. In their heyday, these BBSes were filled with interesting people and warez to fill the most capacious 10 Megabyte hard drive. In an attempt to relive the days of the Internet before the Eternal September, [Jeff Ledger] whipped up a tutorial for dialing up BBSes with an updated classic computer.

Instead of doing this tutorial with a C64 or an Apple II, [Jeff] used the Propeller powered Pocket Mini Computer he designed. This computer features 32Kb of RAM inside an eight-core Parallax Propeller along with a BASIC interpreter to run your own programs.

This Mini Computer can connect to BBS systems, but seeing as how acoustically coupled modems are rare as hen’s teeth these days, [Jeff] thought it would be a good idea to log in to the many Internet connected BBS servers using his desktop as a bridge between the Propeller and the Internet.

After [Jeff] got his Propeller computer up and running on a BBS, he was free to play Trade Wars or slay grues in one of the many MUDs still running. Not bad for a demonstration of the Internet of old, and made even better by the use of a Propeller.