Heat-seeking firebot drowns out the flames

This robot can find and extinguish fires automatically. It is the culmination of an Embedded Design class project from last school year. [Dan] and his classmates developed a turret that holds both a spray nozzle and heat sensor which would be a fantastic building block for a real-life tower defense game.

The jewel of the sensor array is a TPA81 thermopile array. Note the use of the term ‘array’ in the name. This is more like eight temperature sensors aligned with each other. By monitoring them all, the direction from which the most heat is coming can be determined. Once it’s zeroed in on the fire getting water to the right place can be a difficult task. That’s where the other sensors come into play. An accelerometer allows the bot to determine the angle of the spray nozzle (a weed sprayer was used in this case). An ultrasonic range finder and few algorithms let the Arduino which drives it all make sure that the arc of the water lands on the hot spot. This is all shown quite clearly in the clip below the jump.

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LED cyber eyes; more nerdy than just taping your glasses

Regular glasses are okay, but these light up and respond to your movement. [Dr. Iguana] is at it again, designing a very interestingly shaped PCB to augment your visual augmentation devices.

The circuit board has two thin curving wings which conform to the shape of a pair of glasses. In the middle there’s a larger area that holds most of the components but it’s still smaller than a common coin cell battery that powers the device. Over each eye there are a half dozen red LEDs which are driven by a PIC 12F1840. It can flash a bunch of patterns the but the interactivity is the real gem of the project. The doctor included an MMA8450 3-axis accelerometer. As you can see in the clip after the break, shaking your head this way and that will be reflected in the pattern of lights.

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Fantastic programming makes this Arduino gaming device something special

The hardware that went into this Arduino gaming console is just fine. But the coding that produced this game called Twisted SNAKE is beyond compare. [Rodot] has programmed several games for the hardware, which uses an Arduino, 160×168 TFT screen, a 3 axis accelerometer, and two input buttons. If you’re interested, there is a forum thread in which he talks a bit more about the hardware design. But you’re not going to want to pass up either of the two videos embedded after the break.

The first clip shows off a bouncing-ball platforming game. The accelerometer moves the ball back and forth, and the top scrolling level brings more ledges into play. This in itself is a great game. But the Twisted SNAKE game shown off in the second video makes our own ARM-based Snake game look like a 3-year-old programmed it. [Rodot] filled up all of the program memory of the ATmega328 chip to  make this happen. There’s a menu system which allows for color themes and difficulty selection. The game play itself lets the snake travel anywhere it wishes with the tail following behind in graceful curves. Wow!

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Kalman filter keeps your bot balanced

If you’re looking to improve the stability of your self balancing robot you might use a simple horrifying equation like this one. It’s part of the journey [Lauszus] took when developing a sensor filtering algorithm for his balancing robot. He’s not breaking ground on new mathematical ideas, but trying to make it a bit easier for the next guy to use a Kalman filter. It’s one method of suppressing noise and averaging data from the sensors commonly used in robotic applications.

His robot uses a gyroscope and accelerometer to keep itself upright on just two wheels. The combination of these sensors presents an interesting problem in that accelerometer input is most accurate when sampled over longer periods, and a gyroscope is the opposite. This filter takes those quirks into account, while also factoring out sensor noise. Despite the daunting diagram above, [Lauszus] did a pretty go job of breaking down the larger function and showing us where to get the data and how to use it in microcontroller code.

Monitoring a clothes washer with an accelerometer

[Viktor’s] washing machine did a good job of cleaning his clothes, but it kept a bit too quiet about it. The machine doesn’t have an audible alert to let him know the cycle has finished. He decided to build his own alarm which can just be slapped on the side of the machine.

You can see that a couple of magnets hold the board to the metal housing of the washer. The board doesn’t actually connect to any of the machine’s circuitry so this should work about equally as well for any unit. The detection is based on motion, thanks to a Freescale MMA7361 3-axis accelerometer. When he starts a load of wash he flips the power switch for the board on. The PIC 12F683 that drives the device starts monitoring the accelerometer for changes. If it goes for more than about one minute without reading motion the piezo buzzer starts beeping. It’s a fun and easy solution along the same line of this oven pre-heat alarm add-on.

Printing and programming a self-balancer

The Hackaday staff isn’t in agreement on 3d printers. Some of us are very enthusiastic, some are indifferent, and some wonder what if they’re as widely useful as the hype makes them sound. But we think [Jason Dorweiler’s] self balancing robot is as strong a case as any that 3d printing should be for everyone!

Don’t get us wrong. We love the robot project just for being a cool self-balancer. Seeing the thing stand on its own (video after the break) using an Arduino with accelerometer and gyroscope sensors is pure win. But whenever we see these we always think of all the mechanical fabrication that goes into it. But look at the thing. It’s just printed parts and some wooden dowels! How easy is that?

Sure, sure, you’ve got to have access to the printer, it needs to be well calibrated, and then you’ve got to make the designs to be printed out. But these hurdles are getting easier to overcome every day. After all, there’s no shortage of people to befriend who want nothing more than to show off their Makerbot/RepRap/etc.

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Pocketwatch retrofit takes input from accelerometer

A friend of [CNLohr’s] used the mechanism from an old pocket watch in an art piece, but left him with the enclosure. It’s an interesting looking object that feels great in your hand so he decided to fill it with his own electronics, thereby giving it a new life. He’s showing off an early version of the hardware in the video, but plans to send off another version of the board soon to add a few features.

You can see that the round PCB is small enough to fit in the space vacated by the original hardware. The ribbon cable is used to connect to the programmer and we think it’s also the power source for this demonstration. There’s a small Densitron display that’s reading out hex values from the accelerometer. Many of these mems chip (you can learn how they work from this post) include a hardware tap detector. This meant you can tap your finger on the device and the chip will signal an input to whatever chip is attached to it. That’s a great option for user input, and it’s what [CNLohr] chose as the select button here. He tilts the watch to one side, then taps to turn on the LED. That’s all for now, but we like the promise it shows and can’t wait for updates!

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