Active Suspension R/C Car Really Rocks

January 13, 2020 by Kristina Panos 27 Comments

When you’re a kid, remote control cars are totally awesome. Even if you can’t go anywhere by yourself, it’s much easier to imagine a nice getaway from the daily grind of elementary school if you have some wheels. And yeah, R/C cars are still awesome once you’re an adult, but actual car-driving experience will probably make you yearn for more realism.

What could be more realistic and fun than an active suspension? Plenty of adults will never get the chance to hit the switches in real car, but after a year of hard work, [snoopybg] is ready to go front and back, side to side, and even drift in this super scale ’63 Oldsmobile Dynamic 88 wagon. We think you’ll agree that [snoopybg] didn’t miss a detail — this thing makes engine noises, and there are LEDs in the dual exhaust pipes to simulate flames.

An Arduino reads data from a triple-axis accelerometer in real time, and adjusts a servo on each wheel accordingly, also in real time, to mimic a real car throwing its weight around on a real suspension system. If that weren’t cool enough, most of the car is printed, including the tires. [snoopybg] started with a drift car chassis, but even that has been hacked and drilled out as needed.

There are a ton of nice pictures on [snoopybg]’s site if you want to see what’s under the hood. We don’t see the code anywhere, but [snoopybg] seems quite open to publishing more details if there is interest out there. Strap yourself in and hold on tight, because we’re gonna take this baby for a spin after the break.

If this is all seems a bit much for you, but you’ve got that R/C itch again, there’s a lot to be said for upgrading the electronics in a stock R/C car.

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Plucky Kalimba Plays Itself

January 11, 2020 by Kristina Panos 23 Comments

[Gurpreet] fell in love with the peaceful, floaty theme from the Avatar series and bought a kalimba so he could hear it resonate through his fingertips. He soon realized that although it’s nice to play the kalimba, it would be a lot cooler if it played itself. Then he could relax and enjoy the music without wearing out his thumbs.

After doing a bit of experimentation with printing tine-plucking extensions for the servo horns, [Gurpreet] decided to start the design process by mounting the servos on a printed base. The servos are slotted into place by their mounting tabs and secured with hot glue. We think this was a good choice — it’s functional and it looks cool, like a heat sink.

[Gurpreet]’s future plans include more servos to pluck the rest of the tines, and figuring out how feed it MIDI and play it real time. For the demo after the break, [Gurpreet] says he lapel mic’d the kalimba from the back and cut out the servo noise with Audacity, but ultimately wants to figure out how to quiet them directly. He’s going to try lubing the gears and making a sound-dampening enclosure with foam, but if you have any other ideas, let him know down below.

We don’t see too many kalimba projects around here, but here’s one connected to a Teensy-based looper.

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An Arduino-Based Flute Playing Machine

January 11, 2020 by Sharon Lin 9 Comments

It’s one thing to be able to transcribe music from a flute, and it’s another to be able to make a flute play pre-written music. The latter is what [Abhilash Patel] decided to pursue in the flute player machine, an Arduino-based project that uses an air flow mechanism and PVC pipes to control the notes produced by a makeshift flute. It’s currently able to play 17 notes, just over two octaves starting from the lowest frequency of E.

In order to play songs, the tones have to either be directly coded and uploaded to the Arduino, composed with a random note generator, or detected from a microphone. While a real flute can be used for the machine, [Patel] uses a PVC flute, constructed with some knowledge of flute playing.

The resonant frequency is based on the effective length, hole sizes, and pipe diameter, so it is fairly difficult to correctly tune a homemade flute. Nevertheless, calculating the length as c/2f where c is the speed of sound (~345 m/s) and f is the frequency of the note can help with identifying the location of the holes. [Patel] cut the PVC pipe and sealed off one end, drilling a blowing hole at 1.5 x the pipe diameter. After playing the flute, the end of the pipe was filled until the frequency exactly matched the desired note.

The hole covering uses cuttings of pipe attached to a cable connecting to a servo. The motors are isolated inside a box to keep the wires clear and area all able to be powered with 5 V. As for the software, the code is primarily used to control when the fan is blowing and which holes are covered to produce a note.

Listen to the flute play “My Heart Will Go On” from Titanic in the video below. Now the next step might just be making the flute playing machine automatically play sheet music – imagine the possibilities!

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Arduino Pedometer Counts Your Steps

January 10, 2020 by Al Williams 10 Comments

There’s a trend in corporate America that has employees wear a step counter — technically a pedometer — and compete in teams to see who can get the most number of steps. We wonder how many people attach the device to an electric drill and win the competition easily. However if you want to do your own measurements, [Ashish Choudhary] has plans for making a pedometer with an Arduino. The device isn’t tiny, but as you can see in the video below it seems to work.

For the extra size, you do get some features. For one, there is a 16×2 LCD display and an ADXL335 accelerometer, and you can probably imagine some other cool features for such a device.

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Space-Saving Servo Tester Console Looks Space-Worthy

January 5, 2020 by Kristina Panos 7 Comments

You know how it goes — sometimes you just have to stop in the middle of a project and build yourself a tool that vastly improves your workflow as soon as it’s completed. [Ikkalebob] aka [Will Cogley] on YouTube is working on some super secret project that requires a whole bunch of servos. And since all of them have to be tested and set, he built this adorable servo tester as a time-saving gift to himself.

This tester revolves around an Adafruit 16-channel servo driver and an Arduino Uno. The servos show up on the screen in groups of four, and can be tested four at a time with the pots. The buttons let [Ikkalebob] move up and down between the groups. The SainSmart LCD proved to be more difficult to set up than others, but [Ikkalebob] did you a solid and tweaked the library. It’s available along with his code and STLs.

Speaking of STLs, we really dig the mini NASA console look and the folding enclosure. Leveraging the print process to build hinges and other things is awesome, and so is getting away with using fewer fasteners. You can see a bit of how [Ikkalebob] designed it in the video after the break.

Depending on what you’re doing with servos, you might want a different kind of testing suite. Here’s one that’s geared toward RC pilots.

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Arduino Wristwatch Has LED Hands

January 5, 2020 by Al Williams 20 Comments

When you read “Arduino wristwatch”, you fall into the trap of envisioning an Arduino UNO clumsily strapped to someone’s wrist. [Marijo Blažević’s] creation is much more polished than that. A round circuit board holds two surface mount ICs and 12 LEDs. The whole thing looks nice fit snugly inside of a watch body. It isn’t a Rolex, but it does have considerable geek cred without being unwearable in polite company.

One IC is an AVR micro, of course. The other is a DS3231 real time clock with built-in crystal. A CR2032 keeps it all running. The main body, the outer ring, the bottom, and the buttons are 3D printed in PLA. The crystal and the band are the only mechanical parts not printed. The bill of materials shows a 36mm crystal and even provides links for all the parts.

You don’t want to run LEDs all the time because it is bad on the battery. When you press the button once, you get one of the LEDs to light to show the hours. Another press reads the minutes in units of 5 minutes. A third press shows you one of five LEDs to show how many minutes to add. For example, if the time is 9:26 you’d get LED 9 (hours), LED 5 for 25 minutes, and the third press would show LED 1 for 1 extra minute. If either of the minute indicators show 12 o’clock, that indicates zero minutes.

The exciting thing, of course, is that you can program it beyond the code on GitHub. Already it can tell time and display the temperature. You don’t have a lot of I/O, but you ought to be able to get some more options and maybe some flashy LED blinking patterns in if you try.

Baby’s First Jukebox Is Fun For Parents, Too

January 4, 2020 by Kristina Panos 12 Comments

Believe it or not, there’s a $400 toy mp3 player out there for kids. It looks pretty nice, with colorful buttons and a wood console and all, but those features don’t really justify the price tag. [DerThes] wanted one for his 2-year-old anyway, so he made his own ruggedized version for a whole lot less.

The simple and kid-friendly interface lets [DerThes Jr.] choose from one of nine albums to play by pushing one of the candy-colored buttons. The bottom row of buttons handle play/pause and moving through the track list. When mom and dad get tired of listening to whatever the kids are into these days, they can enter the special god mode code to access 99 of their favorite albums.

This baby boombox is built with an Arduino Uno and an Adafruit music maker shield. [DerThes] etched his own PCB to hold the buttons and the pair of shift registers needed to interface them with the Uno. If you’ve never etched before, here’s a good chance to dip your toe in the ferric chloride, because [DerThes] has the transparency in his repo and a line on a nice instructional video.

If you don’t think your toddler is ready to respect a field of momentaries, you could make a jukebox with NFC blocks.

[via Arduino blog]