Primer Tutorials for Arduino IR Remote Cloning and Keyboard Simulation

ir arduino

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.

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Raspis and Arduinos for FM Broadcast Streaming

radio

The biggest Internet provider in Portugal needed a system to turn FM broadcast stations in Angola, Cabo Verde, and Mozambique into a web stream. Like every good project, the people in charge of the engineering turned to Hackaday staples – Raspberry Pis, Arduinos, and TP-Link routers, all stuffed into an awesome modular rackmount cabinet

Each module in this gigantic rackmount system includes an Arduino, a Raspberry Pi, a Silicon Labs Si4705 FM receiver chip, and a TI USB audio capture chip that allows the Pi to turn the audio out from the radio receiver into an audio stream. All the Pis are connected to a 24 port Ethernet switch and to a separate master Raspi that converts data received from each module into an icecast stream.

The engineering behind each module is pretty impressive – they’re all hot swappable, have remote shutdown capability, and have voltage divider on the backplane to detect where in the rack it’s placed. It’s a very cool piece of engineering and a very cool example of using off-the-shelf hardware to do something that could be much, much harder.

Home Theater for One Shakes Souls, Removes Fillings

hmmmm

Sometimes an earth-shaking home theater setup just won’t do. A speaker enclosure can only fill the average sized room with so much sound. [Kevin Bastyr] has figured out a way around this. Do away with the room, and build the home theater INSIDE the speaker enclosure! [Kevin’s] creation is called Humorously Maniacal Milwaukee Makerspace Multimedia Machine, (or HMMMMMM for short). As the name implies, HMMMMMM was created at the Milwaukee Makerspace. The HMMMMMM reminds us a bit of the sensory deprivation chambers which were so popular in the 70’s. HMMMMMM’s purpose in life however, is anything but deprivation. The user (victim?) climbs through a 27” hatch and settles into a reclining position. An LCD display is mounted a comfortable distance away from the users eyes. Then movie (or brainwashing program) begins.

The sound system is what sets the HMMMMMM apart. The HMMMMMM utilises a 5.16 surround sound system. That’s 5 speakers and 16 10″ high efficiency subwoofers. We’re not sure if it would be better to call it a sound system, or a full-out frontal assault on the senses. We’re not kidding when we say senses as well. Bass this loud can be felt as much as it is heard. The HMMMMMM is has been measured at 148.6dB at 40Hz. That’s well into the hearing damage range. To be safe, HMMMMMM users must wear double hearing protection: foam earplugs and earmuffs.

[Kevin’s] graphs aren’t all smoke and mirrors either – he’s an audio engineer by trade, and made his measurements with a laboratory grade 1/2″ Bruel and Kjaer microphone. Sound pressure level testing isn’t without its dangers. During testing the 2050 watt amplifier powering HMMMMMM encountered a fan failure. The amp’s circuit board ended up scorched black with delaminated traces. The HMMMMMM however was none the worse for wear. Future plans for the HMMMMMM include RGB LEDs that flash to the beat, and a smoke machine to create that extra atmosphere when the escape hatch is opened.

Making Logic With Inductors

NOR

We’ve seen NAND and NOR logic gates – the building blocks of everything digital – made out of everything from marbles to Minecraft redstone. [kos] has outdone himself this time with a logic circuit we’ve never seen before. It’s based on magnets and induction, making a NOR gate out of nothing but a ferrite core, some wire, and a diode.

The theory of operations for this magnetic NOR gate goes as follows: If two of the input windings around the core have current passing in different directions, the fields cancel out. This could either be done by positive or negative voltages, or by simply changing the phase of the winding. To keep things simple, [kos] chose the latter. The truth table for a simple two-input, one-output gate gets pretty complicated (or exceedingly cool if you’d like to build a trinary computer), so to get absolute values of 1 and 0, a separate ‘clock’ winding was also added to the core.

One thing to note about [kos]‘ gate is its innovation on techniques described in the relevant literature. Previously, these kinds of magnetic gates were built with square ferrites, while this version can work with any magnetic core.

While this isn’t a very practical approach towards building anything more complex than a memory cell, it is an exercise of what could have been in an alternate universe where tube technology and the transistor just didn’t happen.

3D Printering: Wherein ABS Is Dangerous

printering

A lot of the ‘prosumer’ – for as much as I hate that word – 3D printers out there like the Makerbot Replicator and countless other Kickstarter projects only officially support PLA filament. This has a few advantages from a product development standpoint, namely not necessitating the use of a heated build plate. There are other reasons for not supporting ABS and other filaments, as one of the Kickstarter updates for the Buccaneer printer elucidates (update available to backers only, here’s a mirror from somebody on reddit).

The main crux of the Buccaneer team’s decision not to support ABS is as follows:

We spoke to our legal counsel about it and they told us that if we officially support a certain “material” type then our printer has to go through massive certification to prove that it is totally safe to use or we will/can get sued badly.

Despite the Buccaneer team’s best efforts, we’re sure, their lawyers were actually able to find some studies that showed ABS could affect a person’s health. The issue isn’t with the ABS itself – LEGO are made of ABS and kids chew on blocks all the time. The issue comes from the decomposition of ABS when it is heated.

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Simple 10 Watt LED driver is Hot Stuff

led-driver

[Peter] needed to drive a high power LED for his microscope. Rather than pick up a commercial LED driver, he built a simple constant current LED driver and fan control. We’ve featured [Peter's] pumpkin candle LED work here on Hackaday in the past. Today he’s moving on to higher power LEDs. A 10 watt LED would be a good replacement light source for an old halogen/fiber optic ring light setup. [Peter] started with his old standby – an 8 pin Microchip PIC. In this case, a PIC12F1501. A PIC alone won’t handle a 10 watt LED, so he utilized a CAT4101 constant current LED driver from ON Semi. The PIC performs three tasks in this circuit. It handles user input from two buttons, generates a PWM signal to the LED driver, and generates a PWM signal for a cooling fan.

Control is simple: Press both buttons and the LED comes on full bright. Press the “up” button, and the LED can be stepped up from 10% to 100% in 10 steps.  The “down” button drops the LED power back down. [Peter] even had a spare pin. He’s currently using it as an LED on/off confirmation, though we’d probably use it with a 1wire temperature sensor as a backup to thermal protection built into the CAT4101. It may be overkill, but we’d also move the buttons away from that 7805 linear regulator. Being that this circuit will be used with a microscope, it may eventually be operated by touch alone. It would be a bit surprising to try to press a button and end up with a burnt fingertip!

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Pong Playing T-Shirt

pong playing tshirt

One of our younger hackers just finished off this awesome Instructable on his flexible 14 x 15 pixel, pong playing t-shirt!

[Spencer] has been working on this on and off for the past year, and finally debuted it at a few Halloween parties last month — it was a hit. He’s made the screen out of RGB LED strips, cleverly soldered together into a large flexible panel of 14 by 15 full colour pixels.

An Arduino Mega takes care of the logic to run the game, which [Spencer] wrote all himself! There’s also a cleverly designed controller using a slide-potentiometer and single button. To play back, the computer AI uses about 15 lines of code, which for pong, is more than enough. He’s also made the whole thing removable so you can still wash the shirt. Finally, the batteries and the “Magic Box” go into a pocket for simplicity’s sake.

If you’re interested in making your own, he also has a Github repository of everything you needStick around after the break to see a demonstration of the shirt by [Spencer] himself!

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