<![CDATA[ChipMusic.org - Arduinoboy question]]> https://chipmusic.org/forums/topic/4527/arduinoboy-question/ Mon, 27 Jun 2011 10:33:36 +0000 PunBB <![CDATA[Re: Arduinoboy question]]> https://chipmusic.org/forums/post/71324/#p71324 2PLAYER says:

Ya 220 works just fine. Thanks for the info on improved signal quality. I will surely be using this

]]> Mon, 27 Jun 2011 10:33:36 +0000 https://chipmusic.org/forums/post/71324/#p71324 <![CDATA[Re: Arduinoboy question]]> https://chipmusic.org/forums/post/71183/#p71183 nitro2k01 says:

Actually, I realize the extra resistor was a 4.7k, for those who might be in need of that fix.

http://blog.gg8.se/wordpress/2009/07/26 … -glitches/

]]> Sat, 25 Jun 2011 19:27:00 +0000 https://chipmusic.org/forums/post/71183/#p71183 <![CDATA[Re: Arduinoboy question]]> https://chipmusic.org/forums/post/71123/#p71123 2PLAYER says:

Ah great, thanks. If I can find a 40-50ohm resistor I'll plop it in series otherwise I'll just go ahead with the 220. Thanks nitro

]]> Sat, 25 Jun 2011 04:26:57 +0000 https://chipmusic.org/forums/post/71123/#p71123 <![CDATA[Re: Arduinoboy question]]> https://chipmusic.org/forums/post/71121/#p71121 nitro2k01 says:

kitsch: Actually, you've misread what he said. He said he had 220 ohms but not 270 ohms. 220 ohms is used as the limiting resistor while 270 ohms is used on the secondary side as a pullup. I once played around a lot with that to find that adding a 1.2k (IIRC) resistor from pin 7 (the unconnected pin) to ground could improve signal quality when stealing power from over the link cable. However, I didn't document the tolerances for the 270 ohm resistor. My bet is that 220 ohms will work OK.

]]> Sat, 25 Jun 2011 02:39:24 +0000 https://chipmusic.org/forums/post/71121/#p71121 <![CDATA[Re: Arduinoboy question]]> https://chipmusic.org/forums/post/71118/#p71118 2PLAYER says:

Hah yea I should have remembered I could throw some in series or parallel to get the right resistance. I had been looking at some other schematics for midi in and they had used 280ohm. Wasn't too sure on the amperage so it's why I asked here.

]]> Sat, 25 Jun 2011 02:06:44 +0000 https://chipmusic.org/forums/post/71118/#p71118 <![CDATA[Re: Arduinoboy question]]> https://chipmusic.org/forums/post/71114/#p71114 kitsch says:

If = 12mA

Rl - 270ohm

Vcc is 5V.

its the limiting resistor.  from the 6n138/6n139 datasheets.

there was a handy website i came across that had a table for the different optocouplers and the limiting resistors needed (and an explanation why), but i can't find it at all now hmm

edit - with the x0xb0x i remember this resistor was suggested to be changed if MIDI wan't working right.  this was so long ago, i don't even remember the opto it uses...  but, it should be able to be done.  6n138 is super common, there are a lot of alternate wirings available online but the suggested and most common all use 270ohm for the limiting resistor (to compliment the MIDI requirements i suppose)

]]> Sat, 25 Jun 2011 00:35:25 +0000 https://chipmusic.org/forums/post/71114/#p71114 <![CDATA[Re: Arduinoboy question]]> https://chipmusic.org/forums/post/71111/#p71111 Alley Beach says:

funny shit, that what happend to me too! haha, what i did is get a 220 resister and a 47 ohm resistor and just link them together =]
worked for me =]

]]> Sat, 25 Jun 2011 00:19:13 +0000 https://chipmusic.org/forums/post/71111/#p71111 <![CDATA[Arduinoboy question]]> https://chipmusic.org/forums/post/71079/#p71079 2PLAYER says:

So i have all the parts for my arduinoboy except for the 270ohm resistor (backorder). My question is this: can you swap that out for a lower/higher ohm resistor like another 220 (which i have a ton of) or will this just screw up how the arduino reads the signal?

]]> Fri, 24 Jun 2011 19:12:36 +0000 https://chipmusic.org/forums/post/71079/#p71079