Trying To Measure The Speed Of Light With An Arduino

December 1, 2011 by Brian Benchoff 63 Comments

We know that measuring the speed of light with an Arduino is possible. It’s just that the implementation is hard.

Last month we saw [Udo]’s blinkenlight shield that can be used as a line scan camera. It’s a neat piece of kit, but [Udo] really wants to submit something for the Buildlounge laser cutter giveaway, so he figured measuring the speed of light would be an easy project. If a kid and a chocolate bar can do it, surely it can’t be too hard.

[Udo] hit upon the idea of pulsing a laser pointer and measuring the time of the reflection. Because his blinkenlight shield can be used as a light sensor, all that’s needed is a mirror and a pretty long line of sight. There’s a few problems with the setup though: with the Arduino running at 16 MHz, a photon will travel 19 meters in one clock cycle.

Even with some very clever coding, we’re not really sure detecting an emitted photon is possible at such (relatively) slow clock speeds. We’re thinking [Udo] could source a few hundred meters of optic fiber so the entire experiment could fit on a desk, but feel free to drop a note in the comments if you’ve got a better idea. [Udo]’s demo of his blinkenlight/laser mashup is after the break.

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Custom Massive LED Panel Lights Up The Party

November 30, 2011 by Mike Nathan 12 Comments

giant-led-sign

The guys at BuildLounge wrote us to share a giant LED sign they came across in the submission pile for their “Win a Laser Cutter” contest that’s currently under way. [Stephen Shaffer] helps run a huge party called Fantastic Planet, for which the group typically outsources the lighting arrangements. They got tired of hiring light guys several times a year and built their own mega display for the festivities instead.

The LED sign consists of 1,474 LEDs that output well over 10,000 lumens. The sign was produced for just about $800, which is very reasonable for a display of its size. The whole thing is controlled by a pair of Arduinos paired with 34 MIC5891 shift registers, all mounted on custom designed PCBs that the group produced in-house.

The display looks great, but don’t take our word for it – check out the video below to see it in action.

If you are interested in taking a closer look at how it was built, swing by the build thread to see more details.

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Arduino Weather-station To Internet Bridge

November 30, 2011 by Mike Szczys 10 Comments

Here’s a project that looks to eliminate the PC necessary for pushing weather station data to the Internet. When you think about it, getting data from your own weather sensing hardware to a site like Weather Underground doesn’t require very much processing at all. The largest chunk of the puzzle is a window to the Internet, and that can be easily accomplished with a microcontroller rather than an always-on computer.

In this case, [Boris Landoni] is using an Arduino along with an RS232 shield and an Ethernet shield. The weather station, a La Crosse WS23xx series, already has an RS232 serial port for grabbing the data. The shield is necessary to step the voltage down to levels that will play nicely with Arduino. It also gives you a D-Sub connector for easy hook up. From there he hit up the documentation for Weather Undeground API, writing code to build the necessary string which is pushed over the Ethernet connection at regular intervals.

If your weather station only offers a USB port you’re not out of luck. Using an embedded platform with USB host functionality you can achieve the same results as we see here.

Graphical Programming With The Arduino IDE

November 30, 2011 by Brian Benchoff 46 Comments

The Arduino is an excellent first embedded development kit, provides a great introduction to electronics, and has the potential to get children into programming. [David] thinks throwing C at non-programmers isn’t the best way to learn programming, so he developed ArduBlock , a graphical programming language for the Arduino.

We’ve seen a number of graphical, block-based programming languages in our time, most notably Scratch. [David] found a project called OpenBlocks that serves as the basis for Android App Inventor.

[David] forked the OpenBlocks project and started working on his new graphical programming language. ArduBlocks uses the Arduino IDE, so everything possible in C with an Arduino should be possible with ArduBlocks. There’s a lot of thought put into the design of the blocks – the first iteration was far too ‘busy,’ but [David] cleaned it up and made the projects understandable.

For an absolute beginner, we couldn’t imagine anything better. ArduBlocks would be great for children, and we can’t wait to see a proper implementation of ArduBlocks with a touch screen.

UberFridge Helps Keep Beer Production Going Through The Dog Days Of Summer

November 24, 2011 by Mike Nathan 6 Comments

uberfridge

[Elco Jacobs] used to let his beer ferment in the kitchen, but when things got too hot over the summer, he had to suspend his ale making for a few months. Not wanting to have to put production on hiatus again, he modified an old refrigerator into an awesome fermentation unit he calls the UberFridge.

The refrigerator features two temperature sensors, one that sits in the fermenting beer, and one that measures the temperature of the fridge. This dual probe setup offers him the ability to closely monitor the fermentation process, which he does via a sharp-looking web interface.

An Arduino serves as the PID controller, talking to a wireless router via a serial connection. The Arduino logs and relays data to the router where it can be viewed via a web browser. Not only can he keep tabs on what’s going on inside the fridge, he can reprogram the Arduino via the web interface as well.

Keep reading to see [Elco] explain the ins and outs of his UberFridge – we’re pretty sure you’ll want to build your own after you do.

[via BuildLounge]

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I’ll See Your Launchpad Controlled Arm And Raise You Arduino Controlled Autonomy

November 21, 2011 by Mike Szczys 6 Comments

This OWI robot arm has been hacked to add position sensors and Arduino control. [Chris Anderson] took one look at the Launchpad controlled OWI from earlier today and said “wait a minute, I’ve already posted my own version of that project”. Well, that will teach him not to tip us off about his hacks!

The position control is a really nice addition. Potentiometers added to each of the joints (shoulder, elbow, and wrist) can be read by the ADC pins on the Arduino. Just a bit of calibration will let the microcontroller board know the position of the arm at any given time. The control technique is the same as the Launchpad hack, with one glaring drawback. [Chris] is using the Adafruit motor driver shield. It uses L293D H-bridge chips, but it only has four channels. There are five motors on this arm, so the video after the break shows it moving around without any outside instruction, but you won’t see it grab onto anything since the Arduino can’t move the gripper!

Still, the position feedback makes the case for this version. Just remember to order an extra chip if you want full control.

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Tracking Satellites With An Arduino

November 21, 2011 by Brian Benchoff 13 Comments

The guys over at brainwagon just finished up ANGST, the Arduino n’ Gameduinio Satellite Tracker, a build that displays 160 different satellites in Earth orbit on any SVGA monitor.

The build is of course based off an Arduino and Gameduino shield. A real-time clock is always needed for a satellite tracker, so a DS1307 RTC is thrown into the mix. The satellite data is stored on a 128KB EEPROM that is big enough to hold 750 different satellites and orbits.

The software side of things is a bit trickier. The guys at brainwagon used [James Miller]’s very popular and very old-school PLAN-13 sat tracking software. This orbit calculation program was published in 1983 and has since been ported from BBC Basic to just about every system imaginable.

Once the ANGST is hooked up and powered on, it reads the real-time clock and calculates the position of a satellite. This is done in real-time and updated every three minutes. On the screen, the last orbit (and a little more) is displayed along with the sun and the location of the ANGST. You might not find something like ANGST at the Space Command at NORAD, but we can’t think of a better way to keep track of the cubesats and spy sats above our heads.

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