Posts Tagged ‘Arduino’

Ultrasound and Slow-Motion Recordings of Dojikko

Sunday, April 14th, 2013

The ultrasonic pulses that let Dojikko “see” her surroundings are normally inaudible to humans, but now, you can hear in detail exactly what’s going on. The ultrasound is 40 KHz, about double the highest frequency that most people can hear. When slowed down, not only can you hear the transmitted pulses, but the echoes and the delay between them are clearly audible, too!

[Watch in HD]

I recorded the sound at a very high sample rate (192 kHz – at this rate, the microphones can hear frequencies up to 96 KHz). Afterwards, I slowed down the sound to a quarter of the original speed, 1/8th, 1/16th, etc, even down to 1/128th (at that speed, just 2 seconds would be over 4 minutes long). I also recorded video in slow-motion, but my camcorder can only go up to 200 FPS (1/8th speed when played back at the usual 25 FPS), meaning that lower speeds such as 1/64th aren’t smooth, as I had to futher slow down the video in editing. But the main point of this video is the sound.

[Dojikko] Amusing bug – First test of closed-loop system for moving forwards

Thursday, March 28th, 2013

I tried to implement a closed-loop system to keep the actual speed the same by increasing power to the motors if e.g. stuck on an object. Results were… amusing.

[Watch in HD]

The speed was correctly being calculated from readings from the ultrasonic rangefinder. There turned out to be a combination of 2 problems (a variable overflowing, and something specific to the format of data that the Sabertooth motor speed controller requires), but they’re fixed and it’s working much better now. I’m still fine-tuning it, as it’s still far from ideal, though (either slow to respond or over-aggressive and dangerous, and interferes with other systems such as the part that detects if it’s stuck).

Dojikko, a Clumsy Robot (Demonstration)

Saturday, March 9th, 2013

This is a project I’ve been working on since December 2012. Dojikko explores her environment using an ultrasound “radar” to see, and a compass to tell which direction she’s facing. An Arduino Mega controls everything. She tends to be clumsy due to my lame programming. The battery lasts for about 3 to 3.5 hours non-stop.

[Watch in HD]

I’m currently working on a video showing the construction process, but there’s an awful lot of footage to work through, so I wanted to at least make this video to introduce this project.

The chassis is a LynxMotion A4WD1 (the wheels and motors were included in the A4WD1 kit v3). The pan/tilt mechanism (head) is also a kit from LynxMotion, although the servos that move the head were sourced separately and I’m using nuts and bolts rather than the pathetic excuse of the nylon fasteners that the kit comes with. The ultrasound module is the extremely cheap Chinese HC-SR04, and I’m very impressed with it considering it’s a 10th of the price of the “Ping)))” module that it is an alternative to. I bought a handful of them since they were so cheap, but I’m ending up enjoying the challenge of using only 1 and making use of the pan/tilt servos.

VU Meter Christmas Tree Lights (Test)

Thursday, December 29th, 2011

The 8 sets of lights are responding to the volume of playing music. Each set is made of 80 LEDs. The Arduino in my “soundcase” is controlling them, instead of controlling the 8 lights on the front of the suitcase. The cardboard box holds the original controller boxes that came with each set of Christmas lights, which have been modified (a transistor has been added to switch their outputs).

You can find out more about my soundcase by watching the second half of this video I made about the building process.

[Watch in HD]

The music used in the second part of the video is from the 2nd of 4 parts from the Commodore 64 port of the demo “Second Reality”.

I’m not sure which was harder to do – modify the controller boxes, or put the lights around the tree… -_-;;

(Beta Test) Singing Motors v2: Koi No Tenshi Mai Orite [Jul 2011]

Sunday, December 18th, 2011

Eagle-eyed viewers may notice that I uploaded the singing motor test video with Fuuko’s theme AFTER July. I actually had this Koi No Tenshi video planned for a long time, and wanted to make that video introducing the new singing motors first. =P

Full version is here.

[Watch in HD]

Text from July 2011:

It’s the version 2 of the Singing Motor! This time, there are 2 that can sing a duet together.
I wonder how it can already be 3 years since I made version 1…

The tuning is wrong with the right-hand motor at the start (it’s not easy to get DC motors to spin at just the right speed – they seem to change as they get hotter, too…). The sound and the video were recorded separately. While recording the sound, I had my fingernails rubbing against the cogs so that they’d actually make some sound, but that would’ve meant you couldn’t have seen the motors moving.

Yes, I do have something big planned, but since it’s big, it will probably take a month or so to prepare for / complete. This is just a proof-of-concept with a MIDI that’s in the public domain.

[4 Singing Motors] Koi No Tenshi Mai Orite [HD]

Monday, November 14th, 2011

Now there are 4 motors singing together! Perhaps this is an early Christmas video…? It was originally just going to be a test, but I decided to upload a proper video of it. Still, the sound recording is experimental. I want to find a way that doesn’t hear a thump when a DC motor starts and stops spinning.

The music was used in the Christmas special of the anime Love Hina, and is originally sung by Yui Horie and Yukari Tamura (“Yamato Nadeshiko”).

[Watch in HD]

My laptop runs a program of mine that plays a MIDI file, and sends info about certain notes to an Arduino. The Arduino then shows info on an LCD, switches the 2 stepper motors via 8 MOSFETs, and passes on info for the 2 DC motors to a separate motor speed controller (Sabertooth 2X5), which controls those 2 motors. I think these DC motors are much more suited to the higher notes of a singing voice than the stepper motors are. Likewise, the steppers are certainly better for bass notes. Together, they make a team. =D

The stepper motors and DC motors are running from separate power supplies – 12V for steppers, 15V for DC motors – as I haven’t found a reliable way to compensate for the drop in voltage that the stepper motors cause when they run (this causes the DC motors to slow down a little).

More info is in the video! =)

Singing Motor hurt by Fuuko (Test) [HD]

Sunday, October 9th, 2011

Just a little test for a completely-remade version of the singing motor from 2007 which I made with my brother. This time, it’s controlled by my not-yet-released program Bawami (a MIDI player), via an Arduino and a Sabertooth motor speed controller.

Much more info is in the video, just like old times! =D

[Watch in HD]

Bawami works out the speed the motor needs to run at to hit each note. It sends that info to the Arduino, which displays info on an LCD and passes it on to the motor speed controller, using dithering to improve the resolution from 122 speeds to 488 speeds. In the future, Bawami should be able to control any 2 DC motors at a time, plus the 2 stepper motors I’ve shown in previous videos.

The music is Fuuko Ibuki’s theme, 「は~りぃすたーふぃっしゅ」 (“Hurry, Starfish”), from the visual novel Clannad. It’s a MIDI (which I didn’t make) playing on my program.

Only My Railgun (To Aru Kagaku No Railgun OP) on Stepper Bass Box [HD]

Monday, June 6th, 2011

They’re back! This time, I made the MIDI from scratch myself, specifically for the motors, and used a lot of pitch-bends and subtle vibratos.

[Watch in HD]

Also, if the motors try to jump to a high speed too suddenly, the Arduino now ramps up the speed gradually (although it’s fast to human ears). That means no more nasty grinding sounds like the ones in my previous video, which you should watch for more info on the singing stepper motors and this “stepper bass box”…

Believe it or not, that plasma ball-like program of mine normally runs nice and smoothly, but my MIDI player eats a painful amount of my netbook’s CPU (yes, my computer is still out of action – I’m dual-viewing with that monitor). I’m not sure if I’ll release Biribiri, since it’s only my railgun *is shot*

Since I can’t run a proper video-editing program on my netbook, that credit screen was made on Paint. And that concludes today’s random facts.

Duke Nukem music on Stepper Bass Box [HD]

Saturday, April 9th, 2011

After a little playing around, I’ve found a box that makes these little motors sound much better! These are my “singing stepper motors” in their new-found box, which I’m now naming a Stepper Bass Box, since the motors can’t make high-pitched sounds. The sound is recorded by that black webcam, which has rather nice microphones.

[Watch in HD]

2 pieces of music are played. The first is “Stalker”, the music from stage 1 of “Duke Nukem 3D”, and the second is “RoboCreeping”, from stage 4 of “Duke Nukem 3D: Episode 2″.

A program of mine (which I haven’t released yet) is playing the MIDI files on my laptop and sending the note frequencies to the Arduino, which switches the stepper motors appropriately and displays the note frequencies on an LCD.

I had to edit the MIDIs a little to get them to sound better here, where only 2 notes can play at once. You can find the original MIDIs at somewhere like

Singing stepper motors – Motto ☆ Hade Ni Ne (Kannagi OP) [HD]

Friday, April 8th, 2011

Apologies for the sucky sound quality – it seems these stepper motors aren’t ideal for music, since they’re so quiet. -_-

[Watch in HD]

A program of mine running on my laptop is sending the frequenciesof notes from a MIDI file to an Arduino, which in turn controls 2 stepper motors and shows the frequencies on an LCD. The music is the opening theme to the anime “Kannagi”, 「motto☆派手にね」.

I suppose this is a step up from the “singing motor” videos I uploaded in 2007/2008. With stepper motors, the pitch can be precisely correct! However, the ones I have can’t get very high-pitched, so they’re better for bass (not what they’re doing in this video). At around 00:16, you can hear what happens if one tries to go faster than it can – it just vibrates.

Maybe I’ll try to get some stepper motors which are louder / higher torque / have more steps per revolution, when I have the money to spend on such random things…