DIY Ultrasonic Range Finder For $5

January 24, 2011 by Chris Nelson 25 Comments

After finding some ultrasonic transducers online for a dollar each [Kerry Wong] decided to create an ultrasonic range finder. The result is much like parallax’s PING))) sensor but much cheaper. His post is not only a good way to save some money, but also does a good job of explaining how ultrasonic sensors work. The transmit circuit is essentially an H-bridge, much like what you would use to control a motor. To listen to the returning echo he uses a pair of high gain/low noise op-amps to filter and amplify the signal. The board he uses to test the range finder (not included in the cost) is an ATMega328 running the Arduino boot loader. He also provides lots of example code to boot.

Turning Music Into A Light Show

January 22, 2011 by Chris Nelson 24 Comments

[nickinoki] Made a light show using some amplifiers and an arduino. First he created a microphone circuit based around a LM386 Audio Amplifier. After amplifying the output of the microphone a second time, he uses three bandpass filters to block all but a few desired frequencies from reaching the arduino. By only letting a few frequencies through the arduino is able to determine if the song is louder at higher or lower frequencies. Then using the three analogue inputs he created a scheme for generating the light show on an arduino. While he was unable to achieve the exact target frequencies with his bandpass filters they worked well enough to allow him to successfully generate the light show.

No More Blurry Pictures

January 22, 2011 by Mike Szczys 27 Comments

Say goodbye to ruined images thanks to this add-on hardware. It measures the movement of the camera when a picture is taken and corrects the image to get rid of motion blur. Above you see a high-speed camera which is just there for testing and fine-tuning the algorithm that fixes the photos. Once they got it right, the setup that the camera is attached to only includes an Arduino board, Bluetooth modem, 3-axis accelerometer, gyroscope, and a trigger for the camera. You use the new hardware to snap each image and it takes care of triggering the SLR’s shutter in order to ensure that the inertial data and the image are synchronized correctly.

[Thanks Rob]

Arduino The Documentary

January 19, 2011 by Mike Szczys 38 Comments

We finally got around to watching “Arduino The Documentary” and it’s a two-thumbs-up kind of film. What did we like? It’s a documentary about open source hardware so what’s not to like? You’ll hear the story of how the Arduino team was formed and the path they took from design to production. There are also interviews with early adopters and we even find out that Sparkfun passed on their chance to sell the original through-hole kit version of the board. It’s well made, and thanks to the Creative Commons license you can download it for free, or watch the embedded version here after the break. It’s only 28 action-packed minutes so finish up that special clock and watch it during lunch today.

Continue reading “Arduino The Documentary” →

Attitude Control For A Really Big Rocket

January 18, 2011 by Mike Szczys 42 Comments

If this is meant for a model rocket it must be the biggest we’ve ever seen. [Scott] and [Trevor] took on the task of building a rocket attitude control system after reading about some research on the topic. But that researcher only tested the theories using simulations so they set out to build their own. The prototype above has a tank of compressed Nitrogen which can hold up to 3000 PSI. You can begin to understand why this needs to be used with a big rocket. The pressurized gas is connected through a regulator to four valves which feed nozzles around the circumference of the fuselage. An Arduino takes readings from a gyroscope and actuates the gas valves via a relay board.

You can check out the test rig in the video after the break. The prototype is suspended horizontally from a wire and its orientation held at one position by the system. There’s also a paper (PDF) if you’re interested in the equations that went into the stabilization control. This system would have been right at home on that huge sugar rocket we saw back in October.

Continue reading “Attitude Control For A Really Big Rocket” →

New Year’s Eve Ball Drop In Your Kitchen

January 18, 2011 by Mike Szczys 12 Comments

[Tech B.] hacked together a Ball Drop for New Year’s Eve using stuff he had lying around. The ball itself is an old Christmas ornament that he cut in half and filled with 14 LEDs and a 9V battery. He finished up that portion of the project by gluing the halves back together and adding a hole for the guide rod. The base is made of some cardboard boxes and hides an Arduino, a servo motor, an LCD screen, and the base for the vertical rod. When the last ten seconds of the year are counted down, a servo lowers the ball by unspooling some yarn that loops over the top of the rod. As the yarn is slowly dished out gravity pulls the ball toward its goal. We’ve embedded [Tech B.’s] demonstration video after the break.

Continue reading “New Year’s Eve Ball Drop In Your Kitchen” →

Electronic Dice Has Option For 20 Or 100 Sides

January 17, 2011 by Mike Szczys 17 Comments

[Bluewraith] built himself an electronic dice using a 555 timer and 4017 counter. This is a classic project and he enjoyed doing it but wondered about making a 20-sided dice. So he grabbed his Arduino and got to work. A switch on the final project selects between 20 or 100 sides. He used a MAX7219 to control the 7-segment displays, and a standalone AVR chip for the rest of it.

If you missed it back in October you should also look in on this 6-sided dice. It also uses an AVR running the Arduino bootloader but a mercury switch allows the player to shake the box in order to start a roll.

One last note, we made a conscious decision to use the word ‘Dice’ instead of the grammatically correct ‘Die’ which is its singular version. We think ‘Die’ can be a bit too confusing and we’re not the only ones.