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1  Using Arduino / Microcontrollers / Re: scaling logic signal voltage on: April 17, 2014, 11:40:21 pm
thank you. this has been very insightful... i will opt for using the 74HCT4051! it's exactly what i need.

arschemmel, i apologize and will remember to post the datasheet next time.  smiley-cool
2  Using Arduino / Microcontrollers / Re: scaling logic signal voltage on: April 16, 2014, 07:47:51 pm
so my question doesnt make sense - i apologize.

but i dont see how me misunderstanding a datasheet and asking a question as a result makes me a lazy person.

i am inexperienced, and the title of this thread obviously implies misinterpreted some information i read. but thats what this forum is for - asking questions. right?
3  Using Arduino / Microcontrollers / Re: scaling logic signal voltage on: April 16, 2014, 05:21:31 pm
the way i understand it, it says control LOW voltage should be equal to VSS?

am i wrong?

im very happy if im wrong and my arduino will do the job with no frills!
4  Using Arduino / Microcontrollers / scaling logic signal voltage on: April 16, 2014, 04:27:34 pm
hey list,

so i'd like to use the digital pins of my arduino to switch audio signals on/off using a CMOS4066 chip.

the cmos is powered with -5v and +5v to handle dual ended audio signals - but in order to open/close the CMOS gates i need to pull the control pins from +5v down to -5v.

any idea how i can convert the arduino 0-5v logic signal to something like -5 to +5 ?

thanks!
ú
5  Using Arduino / General Electronics / guitar pickup pre / phase flipper on: April 11, 2014, 06:08:24 pm
hello

i am designing an instrument where i need a preamplifier stage for a guitar pickup, with an arduino controlled CMOS switch that can flip the phase of the buffered/amplified signal.

the switch needs to be a CMOS (i'm using a 4066) for various reasons - so i came up with this circuit combining ideas i found on the internet... it uses both channels of a TL072 IC.

http://i.imgur.com/HM4dIev.jpg

will this design be able to do what i want it to do? i'd love to hear your thoughts on the idea!

thanks for your help,
dataplex
6  Using Arduino / General Electronics / TIP120 vs MJE3055T on: September 18, 2013, 04:39:22 pm
hello,

i have a question - and it is probably a long shot - but a circuit i am building needs a TIP120 transistor to switch a 9v voltage on/off via arduinos digital pins.

i have run out of TIP120's, but found some MJE3055T...

do you think i could make it work?

thank you so much,
ú
7  Community / Exhibition / Gallery / Music In Space - A recent TEDx talk i gave on my Arduino controlled instrument on: July 24, 2013, 08:05:35 am
Just thought i'd share some thoughts on electronic music and it's place in the physical world. More information on the instrument can be found on ulfurhansson.com.

https://www.youtube.com/watch?v=f1XS6lA5REs
8  Using Arduino / Microcontrollers / Re: Standalone Makey Makey on: April 24, 2013, 01:50:04 pm
okay, that would work.... hmmm.... any idea how i would do that? i cant find anything on the subject.... it seems i would have to change the address codes and whatnot...
9  Using Arduino / Microcontrollers / Re: Standalone Makey Makey on: April 24, 2013, 11:11:53 am
@fungus

i cant fit my arduino mega inside the instrument im making... thats why a tiny MPR121 or a makey makey would make the most sense.

is there a way to use the makey makey as a standalone ardunio, controlling 18 logic pins?

10  Using Arduino / Microcontrollers / Standalone Makey Makey on: April 24, 2013, 10:37:04 am
hey

i need to make a 18 key touch sensitive musical keyboard.

i tried the MPR121 and it works great, but it only offers 12 electrodes. i cannot use the capsense library because they keyboard has to be far away from the arduino... the long wires mess with the capacitance readings.

so, the makey makey sounds like a great solution to my problems, but i need to be able to use it without a computer.

can anyone think of a solution where the makey makey can run in standalone mode, with each of the 18 electrodes switching 18 arduino pins on/off?

any thoughts would be greatly appreciated....
thanks !!
11  Using Arduino / General Electronics / Re: NJM2521 audio switch help on: January 17, 2013, 05:53:52 pm
to clarify what kind of instrument this is:

the switch is a part of a musical instrument, where each channel is one note, controlled by a keyboard.

there will be 12 stereo LM1876 amp chips, giving me 24 notes to play with. the outputs of the amp chips dont go to speakers, but rather they go to 24 coils that drive steel strings through magnetic actuation. (its a harp)

the solenoids drive the 24 harp strings by a feedback loop (the input is a piezo pickup, on the bridge - through a preamp)

i have made a similar instrument before, seen here :: ulfurhansson.com.

thats why i need to be able to turn the channels on/off very rapidly, through a digital interface (the arduino)!

so, clicks and pops are fine - they actually could help the strings to start vibrating.

i got the chips from fedex today - for some reason this setup is NOT WORKING



any thoughts on what i might be doing wrong?

here is the datasheet : http://semicon.njr.co.jp/eng/PDF/NJM2521_E.pdf
12  Using Arduino / General Electronics / Re: NJM2521 audio switch help on: January 14, 2013, 01:55:11 pm
because this PCB is a part of a musical instrument, where each channel is one note, controlled by a keyboard. there will be 12 stereo amp chips, giving me 24 notes to play with.

thats why i need to be able to turn the channels on/off very rapidly, through a digital interface (the arduino)!

updated pcb with ground fill ::
13  Using Arduino / General Electronics / Re: NJM2521 audio switch help on: January 14, 2013, 01:09:26 pm
thanks for the reply!

i would be using pin 4 only for a stereo signal, right? mono signal and i would use pin one and pin 8 for ground?

like so:


(PCB is mirrored for printing)
14  Using Arduino / General Electronics / NJM2521 audio switch help on: January 13, 2013, 08:30:30 pm
hey guys

i want to use this IC to switch a line level audio signal on/off, before it goes into a more powerful LM1876 amp :: http://semicon.njr.co.jp/eng/PDF/NJM2521_E.pdf

could anyone help me draw a simple schematic where the arduino digital pins do the switching? im worried about current draw, and don't really understand the test circuit demonstrated in the datasheet...

thank you!
ulfur
15  Using Arduino / LEDs and Multiplexing / Re: LM1876 mute function on: January 11, 2013, 09:47:16 pm
@magician thanks! im using a split power supply, so that wont be a problem. 100kresistors it is then...
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