Converting transparency sheets to an LCD monitor

Apparently, there’s some sort of sporting event being televised this weekend that has been historically used as an excuse to buy a big-screen TV. [Joel] wanted a huge-screen TV on the cheap, so he converted an overhead projector to something he can use with his XBox.

Using a bare LCD panel with an overhead projector is a decades-old hack we’ve covered before. The basic idea is fairly simple, but we’ve never seen anything that could be considered a semi-permanent build. [Joel] started his project by picking up a surplus overhead projector for $25 and routing a cutting board to mount the LCD in. The bulb in the projector added a lot of heat, so three small fans are used to blow air between the projector glass and the LCD display.

[Joel] started off looking at the LumenLab DIY projector project, but considered that to be a terrible amount of work with a fairly high initial investment. If you don’t count the few LCDs [Joel] burned through while building his project, his projector was built for under $100. We’re loving the result and are sure it will be much appreciated at [Joel]’s LAN parties.

Reverse Engineering an AC Signal Protocol

[Arpad] has spent quite a bit of time reverse-engineering a home automation system, and, as he is quick to point out, presents the information learned for informational purposes only. He’s really done his homework (and documented it well), looking into the US patent application, and figuring out how the protocol works.

If you’re wondering how someone is able to send a signal over an AC sine wave, at least one technique is the proprietary [Universal Powerline Bus]. This works by sending precisely times pulses in conjunction with the wave that would exist normally. Given the correct software on the other end, this can then be decoded and used for whatever data transfer is necessary.

Although as engineers and technologists, we certainly don’t condone stealing patents,  part of point of one is that others are allowed to learn your secrets in exchange for some legal protection. [Arpad]’s motivation in doing this is that the technology is only widely available in the US with our puny 120 VAC 60Hz power. With this knowledge, he’s been able to transfer it to work with European 230 VAC 50Hz.

Continue reading “Reverse Engineering an AC Signal Protocol”

A.R.T. sorts your recyclables for you

[Yuhin Wu] wrote in to let us know about the Automated Recycling Sorter that was built with a group of classmates at the University of Toronto. They entered it the school’s student design contest and we’re happy to report that it took first place.

The angled sled has been designed to separate glass, plastic, and metal containers. The first sorting happens at the intake area. A set of moment arms are used to weed out the glass bottles. Since there are several of them in a row, a larger and heavier plastic container will not be falsely sorted and the same goes for smaller glass bottles.

With the glass out of the mix the team goes on to separate metal and plastic. An Arduino was used for this purpose. It senses an electrical disturbance caused by a metal can passing through the chute and actuates a trap door to sort it. Plastic has no effect on this sensor and slides past the trap to its own sorting bin.

Don’t miss both demo videos which we’ve included after the break.

Continue reading “A.R.T. sorts your recyclables for you”

Using routers as displays

Have you ever seen an LED display made out of routers? [Sean] took eight Netgear routers and made an 8×4 display out of them. Because that wasn’t cool enough, a very small version of Conway’s Game of Life was added to the build.

Each router is running a copy of OpenWrt, a Linux distro meant for limited hardware. Instead of an 802.11 protocol, each router runs the B.A.T.M.A.N. advanced mesh protocol. This protocol allows each router to communicate with all the other routers.

Instead of each router receiving data from a master, the routers calculate each step in the Game of Life independently.  Once the routers communicate their initial states, each router is responsible for displaying its four LEDs for each new generation. In the video after the break, you can see [Sean]’s routers calculating random Game of Life boards. Sadly, we didn’t notice a GoL oscillator being randomly generated, but with a 4×8 play field even a Glider wouldn’t last very long.

Continue reading “Using routers as displays”

Weekly Roundup 2/4/12

Another week has come and gone and that means that it is time for our week in review. These are the top posts that have been viewed at Hackaday in the past week.

Coming in at first place is a post about a project by [Red Jones] and [Brian Kast] of Sandia labs. Ethical issues aside, this is a pretty cool project. They have developed a bullet that can be shot out of a smooth-bore gun that can hit within eight inches of a target one kilometer away. That is pretty amazing. It does this magic with an 8-bit processor. This takes the microcontroller wars to a whole new level. Are they using Microchip, Atmel or (gasp) something else?

In second place is a follow up post to our post asking how to control three LEDs with three switches, all in series. That post, although it was posted in December 2011 came in at number three. Getting back on topic though, this week’s post shows how he did it! Not only that, but it shows the extent that he went to when making it. There is footage through the eyepiece of a microscope showing him building one!

Want to use LiPo batteries in your next project but are afraid to use them? Here is a post where [Paul] shows off a circuit that he built that can charge LiPo batteries using a MCP7813 chip from Microchip.

Finally, rounding out the five is a post about a blog that was taken down but luckily not before the IEEE made a copy of it. This blog was made by a robot operator working at the Fukushima nuclear plant and detailed their ongoing cleanup operations there.