There’s no denying it. Super small robots are just cool. [Pinomelean] has posted an Instructable on how to create a mini line following robot using only analog circuitry. This would make a great demo project to show your friends and family what you’ve been up to.
Analog circuitry can be used instead of a microcontroller for many different applications, and this is one of them. The circuit consists of two op-amps that amplify the output of two phototransistors, which control each motor. This circuit is super simple yet very effective. The mechanical system is also quite cool and well thought out. To keep things simple, the motors drive the wheel treads, rather than directly through an axle. After the build was completed, the device needed to be calibrated by turning potentiometers that control the gain of each op-amp. Once everything is balanced, the robot runs great! See it in action after the break.
While not the smallest line follower we have seen, this robot is quite easy to reproduce. What little robots have you build lately? Send us a tip and let us know!
[via Embedded Lab]
Continue reading “A Mini Op-Amp Based Line Following Robot”
[Brian] started out with a clear and concise goal, “allow a regular human to associate an audible tone with a temperature from an infrared contactless thermometer.” With his latest project, the ESPeri.IRBud, he has achieved this goal.
One of our favorite parts of [Brian’s] post is his BOM. Being able to easily see that the IR temperature sensor costs $26 at DigiKey is unbelievably helpful to readers. This specific sensor was chosen because others have successfully interfaced it with the Arduino. Not having to reinvent the wheel is good thing! For the build, [Brian] decided to hook up the IR temperature sensor to a re-purposed flexible iPhone headset wire. Having used headphone sockets to connect to the sensor and speakers, the actual device is quite modular. Hearing this thing in action is quite cool, it almost sounds like old-school GameBoy music! Check it out after the break.
Have you used an IR temperature sensor in one of your projects? Let us know.
Continue reading “Modular Arduino Based Infrared Thermometer”
[Davide] sent us this fun LED matrix mask he built using an ATMega8 and 74LS595N shift registers. Each of the eyes is an 8×8 LED matrix, and the mouth is made from two 8x8s. [Davide] used a ULN2803A Darlington transistor array to drive the matrices.
When the user steps behind the mask, an IR sensor detects that a face is within range and activates the facial features. The code randomly runs the eye and mouth patterns. If the user starts speaking, a microphone element detects his voice and a separate speaking mouth pattern is executed.
The mask body and stand are découpaged with pages from Dylan Dog comics. [Davide] says he built the mask years ago, but decided to submit it to the 2013 Inverart Art Fair in Milan. As you can probably imagine, the mask has been a big hit with the kids so far. Stick around to see [Davide]’s Santa-fied demonstration after the jump. [Davide] didn’t give us any details on that sweet hat, unfortunately.
If you require a better degree of protection or more LEDs, check out this LED helmet.
Continue reading “LED Matrix Mask Will Scare Up Holiday Cheer”
At the end of every semester, we get a bunch of cool and well-documented student projects from Cornell’s ECE4760 class. [Scott] and [Alex]’s infrared theremin is no exception.
The classic theremin design employs each of the player’s hands as the grounded plate of a variable capacitor in an LC circuit. For the pitch antenna, this circuit is part of the oscillator. For the volume antenna, the hand capacitor detunes another oscillator, changing the attenuation in the amplifier.
[Scott] and [Alex] put a twist on the theremin by using two IR sensors to control volume and pitch. The sensors compute the location of each hand and output a voltage inversely proportional to its distance from the hand. An ATMega1284P converts the signal to an 8-bit binary number for processing. They built four voices into it that are accessible through the push-button switch. The different voices are created with wave combinations and modulation effects. In addition to Classic Theremin, you can play in pure sine, sawtooth, and FM modulation.
If you’re just not that into microcontrollers, you could build this digital IR theremin instead. If you find IR theremins soulless or plebeian, try this theremincello.
Continue reading “IR Theremin Speaks In Four Voices”
Hosting a New Year’s Eve party, but don’t want to be stuck behind the bar all night? You could set out a bowl or two of
spiked punch, but where’s the hack? Free yourself from drink slinging duties with the Automated Drink Mixer created by Cornell University students [Justin] and [Austin]. Their design uses a 14″ diameter lazy Susan powered by a 12V bi-directional motor attached to a 2″ rubber wheel. The motor is capable of 70RPM, so the glass ultimately rides around at 10RPM. Orders are entered on a push-button menu. As this is a school project that should adhere to IEEE standards, all libations are non-alcoholic.
The software uses an overarching state machine, so the system polls for input from the menu at idle. When it receives an order, the lazy Susan rotates the glass to the right spout or series of spouts and then returns it to the starting point. [Justin] and [Austin] controlled the position of the glass with an IR emitter and phototransistor. This pair detects the black strips of tape around the edge which are spaced 60° apart. A comparator digitizes the signal and triggers an interrupt in the software, which counts the number of 60° slices. A full demonstration is waiting for you after the jump. Before you jump: drink responsibly, kids. If you aren’t up to that particular challenge, make yourself an alcohol-aware LED ice cube. If you need more LEDs in your life, whip up the Inebriator.
Continue reading “Automated Drink Mixer Is the Life of the Party”
We’ve featured loads of IR Arduino projects and they are all exciting and unique. The projects spring from a specific need or problem where a custom infrared remote control is the solution. [Rick’s] double feature we’re sharing in this article is no exception, but what is interesting and different about [Rick’s] projects is his careful and deliberate tutorial delivery on how to copy infrared remote codes, store the codes with a flavor of Arduino and then either transmit or receive the codes to control devices.
In the case of his space heater an Arduino was used to record and later retransmit the “power on” IR code to the heater before he awakes on a cold morning. This way his room is toasty warm before he has to climb out from under the covers, which has the added benefit of saving the cost of running the heater all night. Brilliant idea if you don’t have a programmable heating system. Maybe he will add a temperature sensor someday so it doesn’t have to run on strictly time.
A more complicated problem was controlling DVD playback software on his computer remotely. [Rick] says he sits at a distance when watching DVDs on his computer but his computer doesn’t have a remote control like a normal TV. Arduino to the rescue again! But this time he pulls out a Teensyduino because of its added feature of being able to emulate a keyboard and of course the computer DVD playback software accepts keyboard commands. Once again he used the “IRremote.h” library to record certain button codes from an old remote control before adding the retrieved codes to a Teensyduino setup and programmed to receive and decode the remote’s IR signals. The Teensyduino then maps the IR codes to known keyboard shortcuts and transmits the simulated keyboard shortcut commands to the computer via its USB cable where the DVD playback software recognizes the key commands.
As always [Rick] shares all his libraries and sketches on his blog so follow the above links to download the files. You will not miss a single step if you follow his excellent videos below. Plus, here are some other ways and other tools for using an IR remote with your Arduino and cloning an infrared remote.
Continue reading “Primer Tutorials for Arduino IR Remote Cloning and Keyboard Simulation”
[Dave Jones] from EEVBlog.com takes “Arduino fan boys” off the garden path getting down and dirty with different methods to capture, evaluate and retransmit IR remote control codes. Capturing and reproducing IR remote control codes is nothing new, however, [Dave] carves his own roads and steers us around some “traps for young players” along the way.
[Dave] needed a countdown timer that could remotely start and stop recording on his Cannon video camera, which he did with simplicity in a previous EEVBlog post using a commercial learning remote control unit. The fans demanded better so he delivered with this excellent tutorial capturing IR codes on his oscilloscope from an IR decoder (yellow trace) as well as using an IR photo transistor (blue trace) which showed the code inclusive of 38 KHz carrier frequency. Either capture method could easily be used to examine the transmitted code. The second lesson learned from the captured waveforms was the type of code modulation being used. [Dave’s] remote transmitted NEC (Japanese) pulse length encoding — which can be assertaind by referencing the Infrared Remote Control Techniques (PDF). Knowing the encoding methodology it was trivial to manually translate the bits for later use in an Arduino transmitter sketch. We find it amazing how simple [Dave] makes the process seem, even choosing to write his own sketch to reproduce and transmit the IR codes and carrier instead of taking the easy road looking for existing libraries.
A real gem of knowledge in the video was when it didn’t work! We get to follow along as [Dave] stumbles before using a Saleae Logic analyzer to see that his transmitter was off frequency even though the math in his sketch seemed correct. Realizing the digital write routine was causing a slowdown he fudged his math to make the needed frequency correction. Sure, he could have removed the performance glitch by writing some custom port control but logic dictates using the fastest and simplest solution when hacking a one-off solution.
[Dave’s] video and links to source code after the break.
Continue reading “Learn to Translate IR Codes and Retransmit Using Arduino”