Arduboy on ATMega4809

Porting Arduboy to the ATMega4809 and making it run on a Arduino Nano Every.

After learning about the Arduboy challenge, we (team Karooza) decided to join in the fun and port Arduboy to a new microcontroller. In the spirit of staying with true 8 bit gaming we chose the ATMega4809. This relatively new microcontroller is also used in the Arduino Nano Every, making it available to the average maker. For this very reason we also chose the Nano Every as our initial target. Then we designed a PCB which handles battery charging, boosting to 5V and breaking out the buttons, LEDs and piezo speaker. Using slightly off-center pads the Nano (with headers) can plug into the breakout board without needing to solder it (a cool idea we borrowed from the Curiosity Nano board).

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World’s Worst Smartwatch

The Singularitron is something of an oddity, to put it lightly. It is simultaneously the worst smartwatch I have ever seen, and also an interesting, highly novel piece of hardware with a certain je ne se quois that has me pining to get my hands on one. Unfortunately, you cannot just pick up a Singularitron at your favorite retailer… well, possibly if your favorite retailer is Sanford and Son Salvage, but aside from that, you have to build your own. Comfortable with that? Well, you still probably cannot make one, because the display has not been manufactured for many years. Impractical? Yes, absolutely, but that is just what developer Zack Freedman was shooting for with this wonderful, awful smartwatch that was designed primarily to be an eye-catching piece for conferences.

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Making a Multiplexed Flip-Dot Display

Flip-dot displays, which use a matrix of actuators to move mechanical pixels into place, are very interesting. At one time they were even very common for transportation displays and the like, where information changes only incrementally.

While modern makers do experiment with such displays, the basic problem with setting one up is that each display unit requires its own actuator. So a 10×10 display would require 100 servos, electromagnets, etc. to flip the dots – a number which increases with the resolution. Various forms of multiplexing are used to simplify the design of electronics displays, so could the same be done with electromechanical flip-dot outputs?

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This sensory extension puppet lets you detect magnetic fields like a bird

Birds have an amazing sense of direction that aids in migrating across vast distances, and scientists think this is due to their ability to detect magnetic fields — just like a compass. Chris Hill on Instructables wanted a way to experience this for himself by using a sensor and some sort of feedback mechanism to feel a magnetic field’s directionality and strength

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The Piano Metronome is key to keeping the beat

In the world of music, being able to keep time accurately is vital when playing a piece, as even small deviations in timing can cause the notes played to sound “off.” Ordinarily a device called a metronome is used to provide consistent ticks that the musician can use, but most are not that visually interesting. This is what inspired ChristineNZ over on Instructables to create her own metronome that uses an Arduino Uno to both show the beat and produce a small noise. 

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‘Hey Google, piss off the neighbors’ – A mad genius built a ‘TallyWhacker’ that noisily activates via Google Assistant command

Do you recall when you were a kid, and there was nothing quite so fascinating as an old-fashioned spring doorstop? You know, the kind that goes “sproi-oi-oi-oing” with any errant tap? A Reddit apartment dweller, having presumably endured one late-night Riverdance rehearsal too many, decided to weaponize this experience.

He attached said sproinger to an activation arm, mounted it to the ceiling, and powered it with an Arduino microcontroller to give it voice activation powers via Google Assistant. Now with the voice command “hey Google, turn on the TallyWhacker,” the arm bar rolls, the tally is thusly whacked, and the upstairs neighbor presumably begins drafting an email to the landlord. To add a bit more fun to the process, the arm bar will oscillate randomly for between five and thirty seconds.

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The 4-20 MA Current Loop

The I/O capabilities built into most microcontrollers make it easy to measure the analog world. Say you want to build a data logger for temperature. All you need to do is get some kind of sensor that has a linear voltage output that represents the temperature range you need to monitor — zero to five volts representing 0° to 100°C, perhaps. Hook the sensor up to and analog input, whip up a little code, and you’re done. Easy stuff.

Now put a twist on it: you need to mount the sensor far from the microcontroller. The longer your wires, the bigger the voltage drop will be, until eventually your five-volt swing representing a 100° range is more like a one-volt swing. Plus your long sensor leads will act like a nice antenna to pick up all kinds of noise that’ll make digging a usable voltage signal off the line all the harder.

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