arduino

2941 Articles

Arduino Lithium Charger Shield

Programmable Lithium Charger Shield For Arduino

November 19, 2014 by 12 Comments

Surely you need yet another way to charge your lithium batteries—perhaps you can sate your desperation with this programmable multi (or single) cell lithium charger shield for the Arduino?! Okay, so you’re not hurting for another method of juicing up your batteries. If you’re a regular around these parts of the interwebs, you’ll recall the lithium charging guide and that rather incredible, near-encyclopedic rundown of both batteries and chargers, which likely kept your charging needs under control.

That said, this shield by Electro-Labs might be the perfect transition for the die-hard-‘duino fanatic looking to migrate to tougher projects. The build features an LCD and four-button interface to fiddle with settings, and is based around an LT1510 constant current/constant voltage charger IC. You can find the schematic, bill of materials, code, and PCB design on the Electro-Labs webpage, as well as a brief rundown explaining how the circuit works. Still want to add on the design? Throw in one of these Li-ion holders for quick battery swapping action.

[via Embedded Lab]

Morse Decoder’s Lean And Sexy Search Algorithm

November 15, 2014 by 27 Comments

Often the Morse Code centered projects that we feature are to help you practice transmitting messages. This one takes a tack and builds an automatic decoder. We think [Nicola Cimmino’s] project is well worth featuring simply based on his explanation of the Digital Signal Processing used on the signal coming in from the microphone. Well done. But he’s really just getting warmed up.

What makes this really stand out is a brilliant algorithm that allows conversion from Morse to ASCII using a lookup table of only 64 bytes. This provides enough room for A-Z and 0-9 without chance of collision but could be expanded to allow for more characters. Below is a concise description of how the algorithm works but make sure you take the time to read [Nicola’s] project description in its entirety.

The algorithm can be decribed as follows. Have an index inside the lookup string inizialied to zero. Have an initial dash jump size of 64. At every received element (dot or dash) halve the initial dash jump and then increase by 1 the index inside the lookup string if a dot was received and by dash jump size if a dash was received. Repeat until a letter separator is reached, at that point the index inside the lookup string will point to the ASCII corresponding to the decoded morse.

Have you heard of this technique before? If so, tell us about it in the comments below. Before you jump all over this one, realize that Magic Morse uses a different technique.

Medical Tricorder Mark I

November 7, 2014 by 16 Comments

A handheld tricorder is as good a reason as any to start a project. The science-fiction-derived form factor provides an opportunity to work on a lot of different areas of hardware development like portable power, charging, communications between sensor and microcontroller. And of course you need a user interface so that the values being returned will have some meaning for the user.

[Marcus B] has done a great job with all of this in his first version of a medical tricorder. The current design hosts two sensors, one measures skin temperature using infrared, the other is a pulse sensor.

For us it’s not the number of sensors that makes something a “tricorder” but the ability of the device to use those sensors to make a diagnosis (or to give the user enough hints to come to their own conclusion). [Marcus] shares similar views and with that in mind has designed in a real-time clock and an SD card slot. These can be used to log sensor data over time which may then be able to suggest ailments based on a known set of common diagnosis parameters.

Looking at the image above you may be wondering which chip is the microcontroller. This build is actually a shield for an Arduino hiding underneath.

There’s a demonstration video after the break. And if you find this impressive you won’t want to miss the Open Source Science Tricorder which is one of the finalists for the 2014 Hackaday Prize.

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The KIM-1 Computer Minified

November 7, 2014 by 18 Comments

The KIM-1 wasn’t the first microcomputer available to computer hobbyists and other electron aficionados, but it was the first one that was cheap. It was also exceedingly simple, with just a 6502 CPU, a little more than 1k of RAM, 2k of ROM, a hexadecimal keypad and a few seven-segment displays. Still, a lot of software was written for this machine, and one of these boards can be found in every computer history museum.

[Oscar] thought the KIM-1 was far too cool to be relegated to the history books so he made his own. It’s not a direct copy – this one uses an Arduino for the brains, only breaking out some buttons, a pair of four-digit seven-segment displays, and the I2C and SPI pins on the ‘duino. The KIM-1 is emulated by the Arduino, allowing for the same interface as an original connected up to an old teletype, and [Oscar] got his hands on the original code for Microchess and the first 6502 disassembler from [Woz] and [Baum].

[Oscar] put the schematics for his version of the KIM-1 up, and has the PCBs up on SeeedStudio. If you’re looking for an awesome replica of a vintage computer and a nice weekend project, here ‘ya go.

Undershield, DIY Arduino Battery Shield

Battery Shield Mounts Underneath The Arduino

November 6, 2014 by 26 Comments

So, what do you do when your Arduino project needs to operate in a remote area or as a portable device? There are LiPo battery shields available, and although they may work well, recharging requires access to a USB port. You can also go the 9v battery route plugged into the on-board regulator of the Arduino but the low mAh rating of a 9v won’t allow your project to stay running for very long. [AI] needed a quick-change battery option for his Arduino project and came up with what he is calling the AA Undershield.

As the name implies, AA sized batteries are used in the project, two of them actually. Yes, two AA batteries at 1.5v each would equal only 3 volts when connected in series. The Arduino needs 5v so [AI] decided to use a MAX756 DC-to-DC step-up regulator to maintain a steady stream of 5v. This article has some nice graphs showing the difference in performance between a 9v battery being stepped down to 5v verses two AA’s being bumped up to 5v.

The ‘under’ in Undershield comes from this shield being mounted underneath the Arduino, unlike every other shield on the planet. Doing so allows use of a standard 0.100″-spaced prototype PCB and is an easy DIY solution to that odd-sized space between the Arduino’s Digital 7 and 8 pins. The Arduino mounts to the Undershield via its normal mounting holes with the help of some aluminum stand offs.

[AI] did a great job documenting his build with schematics and lots of photos so that anyone that is interested in making one for themselves can do so with extreme ease.

A Custom Control Surface For Audio/Video Editing

November 4, 2014 by 19 Comments

Control surfaces (input devices with sliders, encoders, buttons, etc) are often used in audio and video editing, where they provide an easy way to control editing software. Unfortunately even small control surfaces are fairly expensive. To avoid shelling out for a commercial control surface, [Victor] developed his own custom control surface that sends standard MIDI commands which can be interpreted by nearly any DAW software.

[Victor]’s control surface includes several buttons, a display, and a rotary encoder. His firmware sends MIDI commands whenever a button is pressed or the rotary encoder is turned. [Victor] plans on adding menu functionality to the currently unused LCD display which will allow the user to change the scrubbing speed and other various settings.

One advantage of making your own control surface is that you can customize it to your own needs. [Victor] has posted a model of his 3d-printed enclosure and his source code on the project page so you can easily modify his design with any button configuration you might want.

The Tale Of Two Wearable Game Boys

November 3, 2014 by 9 Comments

We’re well past the time when Halloween costume submissions stop hitting the tip line, but like ever year we’re expecting a few to trickle in until at least Thanksgiving. Remember, kids: documentation is the worst part of any project.

[Troy] sent us a link to his wearable Game Boy costume. It’s exactly what you think it is: an old-school brick Game Boy that [Troy] wore around to a few parties last weekend. This one has a twist, though. There’s a laptop in there, making this Game Boy playable.

The build started off as a large cardboard box [Troy] covered with a scaled-up image of everyone’s favorite use of AA batteries. The D-pad and buttons were printed out at a local hackerspace, secured to a piece of plywood, and connected to an Arduino Due. The screen, in all its green and black glory, was taken from an old netbook. It was a widescreen display, but with a bezel around the display the only way to tell it’s not original is from the backlight.

Loaded up with Pokemon Blue, the large-scale Game Boy works like it should, enthralling guests at wherever [Troy] ended up last Friday. It also looks like a rather quick build, and something we could easily put together when we remember it next October 30th.

[Troy] wasn’t the only person with this idea. A few hours before he sent in a link to his wearable Game Boy costume, [Shawn] sent in his completely unrelated but extremely similar project. It’s a wearable brick Game Boy, a bit bigger, playing Tetris instead of Pokemon.

[Shawn]’s build uses a cardboard box overlaid with a printout of a scaled-up Game Boy. Again, a laptop serves as the emulator and screen, input is handled by a ‘duino clone, and the buttons are slightly similar, but made out of cardboard.

Both are brilliant builds, adding a huge Game Boy to next year’s list of possible Halloween costume ideas. Videos of both below.

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