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Video projector from an old single-slide unit

Here’s a video projector that [Matt] hacked together. He needed a small and inexpensive solution to use with his R2D2 build. As you can see in the video after the break, it has no problem playing back the Princess’ distress call. But even if R2D2 is not one of the droids you’re looking for, we think this can be useful in other ways. One use that pops into mind is for projector-based Halloween displays.

As with past projector hacks, all you really need to pull this off is a light source, an LCD screen on which you can playback video, and a lens to focus the light onto a screen. Usually the LCD is the most expensive part of the project and building an enclosure to the correct dimensions can be a bit difficult. [Matt's] solution was to use an MP4 knockoff media player. The rest of the setup is a ’50s era slide projector. The screen from the media player is about the same size as a single film slide, so he removed the screen from the case and put it where the slides go.

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555 Two-fer – Baby swing upgrade and a Headphone tube amp

baby_swing_tube_amp

[Jason] sent in two 555 timer driven items that were worth sharing, both of which are entries in the 555 Design Contest.

The first item is a circuit that automatically resets an infant swing. [Jay], who built both items, has an infant swing for his daughter that spins a mobile and plays music. It’s great but it only works for 7 minutes and 15 seconds before a button push is required to trigger it again. He found this limitation to be annoying, and as I have owned the same swing, I can echo his frustrations. He probed the swing and found that a 5v pulse was required to reactivate the mobile, but it had to be sent after it turned off to have any effect. He put together a simple circuit that would do the button pushing for him, as you can see in the video below.

[Jay's] other entry is a headphone tube amp using a quartet of 6DJ8 vacuum tubes. The 555 timer in the amp is used to drive a FET and the hand-wound transformer he built for the amp. You can see a video of the amp in action below as well.

The projects are lacking a thorough write-up, but he does provide schematics for both the swing reset switch and the tube amp for those looking to replicate either item.

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Debugging MSP430 using Eclipse

[Springuin] just posted a tutorial about debugging MSP430 projects using Eclipse. He read our feature about debugging under IAR, a proprietary IDE which TI offers as a code-limited freebie with the TI Launchpad. In that writeup we wondered if anyone would put together a tutorial using open source tools like DDD and GDB to make debugging easier for those that choose to use operating systems other than Windows. Even though he didn’t directly use those particular packages, this should work just as well.

Eclipse is a popular IDE for many different languages like C, C++, Java, and others. We’ve already seen it used to develop for the TI Evalbot on Linux systems. [Springuin] is using the Java-based IDE on a Windows system, and this is the first time we recall seeing directions on using an open-source alternative for programming with the TI Launchpad under Windows. That being said, the only real Windows specific parts are the steps necessary for communicating with the programmer. Since this method uses MSP-GCC and msp430-gdbproxy, it should be easy to do this under Linux as well. Use our tutorial to set up those tools if you haven’t already, then follow this one for a setting up and debugging in the Eclipse environment.

Der Wafflemeister 3000

der_wafflemeister3000

When people think about robots, a few different things come to mind. We like robots because they take care of tedious work. Robots are great for accomplishing tasks in hazardous environments too. When the [Chalmers Robotics Society] thinks about robots however, they think, “Breakfast!”

The CRS constructed a sweet automatic waffle cooking machine known as the Wafflemeister3000. It can produce up to 5 waffles at a time, cooking them to a nice golden brown in a little over 3 minutes. Think about that for a second – that’s about 90 waffles an hour!

This project isn’t exactly new, with the second iteration having been completed in 2007. However, since the third version features a 400% increase in production volume, we thought it was worth a mention.

Be sure to check out the video below of the Wafflemeister3000 doing its thing.

[via Neatorama]

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Vanishing point robot guidance

Students at the National University of Computer and Emerging Sciences in Pakistan have been working on a robot to assist the visually impaired. It looks pretty simple, just a mobile base that carries a laptop and a webcam. The bot doesn’t have a map of its environment, but instead uses vanishing point guidance. As you can see in the image above, each captured frame is analyzed for indicators of perspective, which can be extrapolated all the way to the vanishing point where the green lines above intersect. Here it’s using stripes on the floor, as well as the corners where the walls meet the ceiling to establish these lines. From the video after the break you can see that this method works, and perhaps with a little bit of averaging they could get the bot to drive straight with less zig-zagging.

Similar work on vanishing point navigation is being done at the University of Minnesota. [Pratap R. Tokekar's] robot can also be seen after the break, zipping along the corridor and even making turns when it runs out of hallway.

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Machine pushes cellphone buttons from anywhere in the world

[Mok Young Bacq] works on the weekends for mobile game monitoring service. He has three cellphones that he uses for work, and although you would think this means he could work from anywhere in the world, the roaming charges are a killer. His solution was to build an incredibly intricate machine that can use three different cellphones (PDF) on his behalf.

Above you can see it perched underneath the apex of the ladder, but you’re definitely going to want to watch the video after the break. This interface method uses a camera to look at each phone. It’s hung pointing downward and moves like a pendulum to look at one of the three screens at a time. Each phone has one servo motor for each button, which uses a flexible cable as an actuator. Now he can take trips abroad, just checking in over the Internet for his two 17-hour weekend shifts (10am to 3am the next morning) working the phones.

This reminds us of the cellphone endurance tests. What happens when a button stops working?

[Read more...]

Let there be light inside picture frames

[Limpkin] picked up a beautiful painting of Budda while in Bali because he thought it would react well with different colors of lighting. His overall goal was to create a picture frame with built-in LEDs. The major design specification for the project was to provide an indirect light source that would not shine in the viewers eyes. He got down to business designing a frame using SolidWorks for his modelling. The final design has a separate track from the paining with small dividers for each diode.

After about four hours on the CNC machine it was time to get down to soldering. [Limpkin] had 576 RGB LEDs on hand. He’s not looking to drive them individually, just to have independent control of each color. This makes the soldering a bit easier as there will be just three MOSFETs to drive each color. The final product looks great and can display any mix of colored light. Not bad for 50 hours of soldering.

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