What the formula i × 100 Hz produces is essentially the harmonic series of a note between G2 and G#2 (in scientific pitch notation), assuming A4 set to 440 Hz. This means the tone of pin 2 is an octave above the first, pin 3 a perfect fifth above pin 2, pin 4 a perfect fourth above pin 3 etc. The reason why it sounds "musical" is pins 3 to 5 forming a construct called second inversion of a major triad (somewhere between G and G# major in this case). If you want a piano-like "touchboard" with equal temperament (octave divided into 12 semitones) you can choose some base note, e.g. "middle C" (C4) with f ≈ 261.6 Hz and calculate the frequencies as f_tone = f_base × pow(2.0, i/12.0). As you can see, if we set i = 12 we get f_tone = 2 × f_base which is exactly one octave above the base note. With that few pads I'd probably go for something simpler though, like the pentatonic scale.
I had that thing lying around for years now, never wanted to play with it because I didn't like the need for a level-shifter - but recently found out that you don't need one. I2C is an open-collector bus with pull-up resistors (here to 3.3V on the board), which are fine to connect directly to the Arduino. BTW the MPR library uses some initialization values for the MPR121 that I find somewhat implausible (and not recommended in the manuals), so with some tweaking there it's a bit more responsive (reliable at detecting touches).
Hi there, I’d like to replicate this build to replace the buttons on my playstation controller for touch buttons. How did you manage to use the board without the level-shifter? Or do I just have to pick a 3.3V main chip?
@@James-uz9se 3.3V supply from Arduino's 3.3V pin, SCL and SDA directly to Arduino's I2C pins (e.g. 5 and 4 for Nano/Uno). The "Pro Micro" 5V/16MHz does not have a 3.3V pin, so if you want to use a pro micro, get a 3.3V/8MHz version. (One is on it's way to me, too.)
BTW, adding a library via the zip file was available in the IDE 1.5.8 possibly earlier versions too. If you launch an earlier version and go Import Library->Add Library, you will notice that the "File Type" selector says "Zip files or folder". It is easily overlooked.
3.3V is an older comman standard parralell with the 5V (fox. for som old computer related IC ) so my guess is that it was easy to develop for that standard or it just happened to be compatible wit some other equpiment the developers had in mind.
It looks to me that the chip is not properly alligned with traces on the pcb. The pins 6 en 7 don't seem to be soldered on the traces but just next to them.
@@ThatGuy-nv2wo I don't understand. I'm pretty sure you can just 3.3 volt output on the arduino. Can you explain the no data part? Because I'm looking at the layout of the arduino and can't see any difference between each pin.
You've made a better continuity buzzer than almost any multimeter has (well, except that it's continuity to you..) This is what's meant by a latched buzzer, too many people reviewing meters on their electronics themed youtube channels think that it's when a continuity buzzer is implemented as a software add on to the resistance measurement and therefore only buzzes after it autoranges resitstance and then complain "it's latched but it's really slow".
Hello Iulian, you should take a look at the TI MSP430 controller ; this controller has built in touch sensor inputs and other nice features (e.g. low power!). Also its almost Arduino compatible if you use the Energia IDE. Regards Andreas
If the I2C pins are not 5V tolerant, the IRQ pin most likely isn't either. I2C pins are essentially open collector outputs so I am sure they use the same output stage on the IRQ pin as well. On the other hand on many digital 3.3V devices the pins are 5V "tolerant" as long as you prevent a large current from flowing. It is an abuse of the internal ESD protection diodes, which will short everything higher than Vdd+diodedrop to Vdd. Don't do that on opamps though. A voltage outside the supply rails can lead to latchup and you opamp will go up in flames immediately (don't ask how I know that).
May I suggest 2 things? 1) try using a fine tip on your soldering iron and just run it over the "bad" IC pads. If that doesn't work it could be the circuit board its self. Wouldn't surprise me that they don't test the boards before mounting the components and they obviously don't test the boards after they are assembled. 2) Not a big deal for testing but next time use the pin number plus 1 for the tones. ;-)
you can regule the frequency now need work with a 1/4 hp motor need make sawstop but with capacitor and ardiono with arduinocapacitor.h this not work the frequency always change do you have any test about?
Hello I wish you can reply to me, My question is: Can I get an analog values from this sensor? My project is an artificial hand and i want a feedback sensor so that once the holds something, the motor stops, please help
You didn't have to travel all the way to Japan in order to find coins with holes you know. The Danish krone 1, 2 and 5 coins also have holes in the them, the Norwegian krone has holes too! :)
See the absolute ratings section for IRQ VSS - 0.3 to VDD + 0.3 Hence the pull-up to only 3.3v. Easy thing to miss, most open collector/drain outputs don't usually have much head room. An easy trap for you young players as Dave would say.
not sure its the best time to re-release the stylophone! those tones remind me of very old games where they were just simple beeps with a simple base 10 offset, not real musical notes of the later games
Hi everyone, I'm making a 12 capacitive sensors and I've got the Uno with Adafruit MPR121 (12 capacitive touch sensors). I want to make each sensors act like the computer keyboard. ("awsedftgyhuj" keys) in order to instruments on Ableton Live for example. However I don't know about programming at all. Would someone help me?
I love how all of his one day projects actually take like 3 years because he does so many projects at the same time that they all take super long
Please come back to this soon, I found it fascinating. I'm off to order the same module to have a play with.
What the formula i × 100 Hz produces is essentially the harmonic series of a note between G2 and G#2 (in scientific pitch notation), assuming A4 set to 440 Hz. This means the tone of pin 2 is an octave above the first, pin 3 a perfect fifth above pin 2, pin 4 a perfect fourth above pin 3 etc.
The reason why it sounds "musical" is pins 3 to 5 forming a construct called second inversion of a major triad (somewhere between G and G# major in this case).
If you want a piano-like "touchboard" with equal temperament (octave divided into 12 semitones) you can choose some base note, e.g. "middle C" (C4) with f ≈ 261.6 Hz and calculate the frequencies as f_tone = f_base × pow(2.0, i/12.0). As you can see, if we set i = 12 we get f_tone = 2 × f_base which is exactly one octave above the base note.
With that few pads I'd probably go for something simpler though, like the pentatonic scale.
I had that thing lying around for years now, never wanted to play with it because I didn't like the need for a level-shifter - but recently found out that you don't need one. I2C is an open-collector bus with pull-up resistors (here to 3.3V on the board), which are fine to connect directly to the Arduino.
BTW the MPR library uses some initialization values for the MPR121 that I find somewhat implausible (and not recommended in the manuals), so with some tweaking there it's a bit more responsive (reliable at detecting touches).
Hi there, I’d like to replicate this build to replace the buttons on my playstation controller for touch buttons. How did you manage to use the board without the level-shifter? Or do I just have to pick a 3.3V main chip?
@@James-uz9se 3.3V supply from Arduino's 3.3V pin, SCL and SDA directly to Arduino's I2C pins (e.g. 5 and 4 for Nano/Uno).
The "Pro Micro" 5V/16MHz does not have a 3.3V pin, so if you want to use a pro micro, get a 3.3V/8MHz version. (One is on it's way to me, too.)
Good video! Those coins are Japanese ¥50 by the way ;-)
BTW, adding a library via the zip file was available in the IDE 1.5.8 possibly earlier versions too. If you launch an earlier version and go Import Library->Add Library, you will notice that the "File Type" selector says "Zip files or folder". It is easily overlooked.
Julian great video. I just had yo go and get this module. I wonder what kinds of things I will make with it?
Nice info, thanks for sharing it :)
3.3V is an older comman standard parralell with the 5V (fox. for som old computer related IC ) so my guess is that it was easy to develop for that standard or it just happened to be compatible wit some other equpiment the developers had in mind.
Hey, do your pennies also work behind a sheet of paper or do they need a direct contact to the skin?
It looks to me that the chip is not properly alligned with traces on the pcb. The pins 6 en 7 don't seem to be soldered on the traces but just next to them.
why not just use the 3.3 volt output on the arduino ?
No data
@@ThatGuy-nv2wo I don't understand. I'm pretty sure you can just 3.3 volt output on the arduino. Can you explain the no data part? Because I'm looking at the layout of the arduino and can't see any difference between each pin.
@@TheRandolph23 Could it be that even though the vcc would be 3.3, the data/clock etc would still be at 5v?
You can just use 3.3v: th-cam.com/video/tTMsbL0eH_M/w-d-xo.html
Is the library sensitive to pressure?
What can we do when need to read lots of capacitive switches? (For example, Creating a PC keyboard needs at least 102 switches)
You've made a better continuity buzzer than almost any multimeter has (well, except that it's continuity to you..)
This is what's meant by a latched buzzer, too many people reviewing meters on their electronics themed youtube channels think that it's when a continuity buzzer is implemented as a software add on to the resistance measurement and therefore only buzzes after it autoranges resitstance and then complain "it's latched but it's really slow".
Hello Iulian,
you should take a look at the TI MSP430 controller ; this controller has built in touch sensor inputs and other nice features (e.g. low power!).
Also its almost Arduino compatible if you use the Energia IDE.
Regards Andreas
Why didnt you use npn transistor for the touches. It does the same and is a lot cheaper
If the I2C pins are not 5V tolerant, the IRQ pin most likely isn't either. I2C pins are essentially open collector outputs so I am sure they use the same output stage on the IRQ pin as well.
On the other hand on many digital 3.3V devices the pins are 5V "tolerant" as long as you prevent a large current from flowing. It is an abuse of the internal ESD protection diodes, which will short everything higher than Vdd+diodedrop to Vdd.
Don't do that on opamps though. A voltage outside the supply rails can lead to latchup and you opamp will go up in flames immediately (don't ask how I know that).
How to use it touchless sensor capability.....i.e how to use proximity?
How can we do that with an easy8051a motherboard, any video on that?
Nice project!
You did an excellent job wiring & soldering. What power magnifier are you using as a visual aid?
Thanks for sharing!
A B Just 3.5D reading glasses from the pound shop.
Julian Ilett Hmm.. It appeared to be higher power. Nevertheless... great job!
Thanks for sharing!
May I suggest 2 things?
1) try using a fine tip on your soldering iron and just run it over the "bad" IC pads. If that doesn't work it could be the circuit board its self. Wouldn't surprise me that they don't test the boards before mounting the components and they obviously don't test the boards after they are assembled.
2) Not a big deal for testing but next time use the pin number plus 1 for the tones. ;-)
does it possible to be use for water level sensor?
thank u for sharing your valuable knowledge!
can i use touch pad to this??
how can i interface this touch pad with arm7 ??
your help is appreciated!
how have you added your libs before? i have always just chosen a zip file...
I've always selected the uncompressed library file, and had to change the name by removing 'master'.
Oh. OK, worked before like this already though :)
I use the Arduino library manager to source most libraries, you don't have to hunt all over for them, and it automatically updates your library lists.
you can regule the frequency now need work with a 1/4 hp motor need make sawstop but with capacitor and ardiono with arduinocapacitor.h this not work the frequency always change do you have any test about?
Hello
I wish you can reply to me,
My question is:
Can I get an analog values from this sensor? My project is an artificial hand and i want a feedback sensor so that once the holds something, the motor stops, please help
You didn't have to travel all the way to Japan in order to find coins with holes you know. The Danish krone 1, 2 and 5 coins also have holes in the them, the Norwegian krone has holes too! :)
they probably hate their monarchs cause they're punching through their heads :D
Haha, no monarchs on them! The ones that do, don't have the hole ;-)
PuchMaxi1988 my (Dutch) coins are Euro coins with the King on one side of them (or the former Queen) and have no holes :)
See the absolute ratings section for IRQ
VSS - 0.3 to VDD + 0.3
Hence the pull-up to only 3.3v.
Easy thing to miss, most open collector/drain outputs don't usually have much head room. An easy trap for you young players as Dave would say.
Im sure that if you use adafruits libary you have to use fruit as the sensors.
is it moultitouchable?
Yes, it is :)
Great video as always =)
The coins are 50Yen Japanese coins though ;D
nin0bb Oops! Sensible Japanese people ツツ
not sure its the best time to re-release the stylophone! those tones remind me of very old games where they were just simple beeps with a simple base 10 offset, not real musical notes of the later games
you could make a phone dialer
so much for one day :D
Hi everyone, I'm making a 12 capacitive sensors and I've got the Uno with Adafruit MPR121 (12 capacitive touch sensors). I want to make each sensors act like the computer keyboard. ("awsedftgyhuj" keys) in order to instruments on Ableton Live for example. However I don't know about programming at all. Would someone help me?
Lolz! I never realized that I needed 3.3v on the low side and 5v on the high side on the level converter.
en.wikipedia.org/wiki/Musical_note#Note_frequency_.28hertz.29
There you have the relation of the frequencies and the notes
Can you give me this MPR121 library, please?
Vaya, pensé que eran monedas de 5 duros :(
Somewhere online right now a Japanese super far right group is planning what they should do for this great insult against their currency. ;)
donpalmera Dammit, I should have used the Norwegian Krone instead!
Julian Ilett As a Norwegian, I approve ;)
maybe Norway has such a far right group as well :D
its japanese 50 yen coin.....
Fake project that's why the final result is not shown.