Autonomous helicopter works like a Wii remote


[Jack Crossfire] took one of those inexpensive indoor helicopters and made it autonomous. He didn’t replace the hardware used for the helicopter, but augmented it and patched into the remote control to make a base station.

The position feedback is provided in much the same way that the Wii remote is used as a pointing device. On the gaming console there is a bar that goes under the TV with two IR LEDs in it. This is monitored by an IR camera in the Wii remote and used to calculate where you’re pointing the thing. [Jack's] auto-pilot system uses two Logitech webcams with IR filters over the sensors. You can see them mounted on the horizontal bar in the cutout above. The helicopter itself has an IR LED added to it that is always on. The base station follows this beacon by moving the cameras with a pair of servo motors, calculating position and using it when sending commands to the remote control’s PCB.

Don’t miss the demo video of the rig after the break.

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Beefing up a smoke alarm system with video, temperature, and connectivity

Here’s a little smoke detector hack which [Ivan] has been working on. He wanted to extend the functionality of a standard detector and we’re happy to see that he’s doing it with as little alteration to the original equipment as possible (this is a life-saving device after all). He sent all the build images for the project to our tips line. You’ll find the assembly photos and schematic in the gallery after the break.

As you can see his entry point is the piezo element which generates the shrill sound when smoke as been detected. He connected this to his own hardware using an optoisolator. This allows him to monitor the state of the smoke alarm on his server. It then takes over, providing a webpage that display’s the board’s temperature sensor value and streams video from an infrared camera.

Of course this is of limited value. We’ve always made sure that our home was equipped with smoke detectors but the only time they’ve ever gone off was from normal cooking smoke or after an extremely steamy shower. But still, it’s a fun project to learn from and we’ve actually got several of the older 9V battery type of detectors sitting in our junk bin.

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Dimming the living room lights using your TV remote

As part of a complete home theater setup [Andy] wanted to be able to control the lights from his couch. He started thinking about the best way to do this when he realized that his TV remote has buttons on it which he never uses. Those controls are meant for other components made by the same manufacturer as the TV. Since he doesn’t have that equipment on hand, he built his own IR receiver to switch the lights with those unused buttons.

He monitors and IR receiver using an AVR microcontroller. It is powered from mains via the guts from a wall wart included in the build. Also rolled into the project is a solid state relay capable of switching the mains feed to the light circuit. [Andy] mentions that going with a solid state part mean you don’t get that clicking associated with a mechanical relay. An electrical box extension was used to give him more room for mounting the IR receiver and housing his DIY circuit board.

Scary Putin guards your stash

If anyone tries to take anything from this coin bank they’re going to have to brave the creepy looks that [Vladimir Putin] gives them. That’s because [Overflo] rigged up the wall hanging to react when you approach it. It’s all in the eyes, which open and turn red based on your proximity to the picture frame.

The frame itself is the ugliest thing [Overflo] could find at Ikea. He spray painted it gold and added an image of [Putin] with a zany background. At rest [Vlad] has his eyes closed. But the lids are connected to a servo motor to pull against the spring that keeps them shut. An infrared proximity sensor is used to trigger the eyelids when you get relatively close, but if you reach out your hand it will even light up the red LEDs hidden in the pupils of the eyes. See a demonstration of the setup in the video after the break.

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Arduino Tachometer tutorial

This tutorial will guide you through the process of building a tachometer around an Arduino. Tachometers are used to measure rotation rate in Revolutions Per Minute (RPM). You don’t need much in the way of hardware, this version uses an Infrared beam to measure fan speed. As with last year’s PIC-based tutorial, [Chris] is using a character LCD to output the reading. Wiring and driving the LCD ends up being the hardest part.

An IR transmitter/receiver pair are positioned on either side of the fan. When the blade passes in between then, the receiver shuts off a transistor connected to one of the Arduino’s external interrupt pins. He shows how to use this interrupt to measure the amount of time between the passing of each fan blade. If you divide for the number of blades, and average the reading for greater accuracy, you can easily calculate RPM.

Another alternative would have been to use a reflectance sensor which allows to for the transmitter and receiver to both be on the same side of the fan.

Use your TV remote as an HID mouse

[Vinod's] latest project lets him use a TV remote control as a mouse. It may not sound like much, but he did it with a minimum of hardware and packed in the maximum when it comes to features.

He’s using an ATmega8 to read the remote control signals and provide USB connectivity. With the V-USB stack he enumerates the device as an HID mouse. One note of warning, he used the PID/VID pair from the USBasp programmer project. If you use that programmer you’ll need to uninstall the drivers to get this to work (we think this is only necessary on a Windows box).

The cursor can be moved in eight directions using the number pad on the remote. The numeral five falls in the center of the directional buttons so [Vinod] mapped that to the left click, with the zero key serving as right click. He even included the scroll wheel by using the volume buttons. The firmware supports cursor acceleration. If you hold one direction the cursor will move slowly at first,then pick up speed. Fine adjustments can be made by single clicking the button. Check out his demonstration embedded after the break.

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Cat trainer will keep them off the counters

Our cats are not allowed on the kitchen counters, and [Iron Jungle] has the same rule. But he spotted some foot prints on the hood above his range and the addition of a security camera caught this picture of [Kelso] breaking the rules. Since he’s not always around to make the fur-ball behave he built an electronic cat trainer to do it for him.

The functionality needed isn’t very intricate. You need to monitor when the cat is where it shouldn’t be and then chase it away. For the latter he grabbed an infrared range finder. When the cat passes in front of the sensor it will trigger the second part of the system: a high-pitched buzzer that’s extremely loud. Any microcontroller will have no trouble driving the system. In this case it’s a PICAXE 28X1.

You can see the trainer in action after the break. It definitely works, because just playing the video chased our own sleeping kitty out of the room.

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