MP3 trigger and LMNC Big Button problem

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ripvanwinkle
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MP3 trigger and LMNC Big Button problem

Post by ripvanwinkle » Tue Jun 16, 2020 10:37 am

Hi,
First of all I'm new to this forum so maybe I've not searched enough but I've tried and I didn't find the right solution for my problem.

So I decided to build LMNC Big Button sequencer and in addition to this I've build Sparkun's mp3 trigger device. The main problem is that mp3 trigger seems to constantly triggering by Arduino even when there is no actual signal coming. Big Button gives stable 0.2v when there is no action, and when I give some sequence I see this on multimeter by various voltage jumping all positive so I'm guessing that the Big Button is OK. I'm guessing that there is a problem with my "inspired LMNC wav trigger" thing.

So, are there any solutions to this problem? I am battling with this thing for days :bang: I AM NOT an advanced builder i'm only beginner both with programming and DIY building so also it can affect but I don't see any bad soldering and error. I really appreciate any advice from you guys.

PS; Recently I've searched that Tsunami trigger works by shorting inputs or via 3.3 positive voltage (I think that mp3 trigger also), but I have no idea what to do with this thing.

KSS
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Re: MP3 trigger and LMNC Big Button problem

Post by KSS » Tue Jun 16, 2020 9:56 pm

Sorry I don't have an answer for you but I DO want to say Welcome to Muffwiggler, ripvanwinkle!
I'm sure someone will be by shortly to answer your question!

Synthiq
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Re: MP3 trigger and LMNC Big Button problem

Post by Synthiq » Wed Jun 17, 2020 3:36 pm

The trigger inputs are active low. If the sequencer has active high outputs, the signals should be inverted. A hardware solution would be to add a npn transistor for each trigger input with emitter to ground collector to trigger input and drive the base from the sequencer via a ~100kohm resistor. It may also be possible to invert the signal in the Arduino code, but be aware that at least trig4 and trig5 can't handle 5V signals and could be damaged if driven from a 5V Arduino but would work fine with a 3.3V Arduino.

ripvanwinkle
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Re: MP3 trigger and LMNC Big Button problem

Post by ripvanwinkle » Tue Jun 30, 2020 3:03 pm

Synthiq, thanks for the advice! For the past few days I kinda abandoned this project but now I'm back. Do you recommended some specific kind of npn transistor? Curently I'm only have some BC547 B 's. They're gonna do the work?

Synthiq
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Re: MP3 trigger and LMNC Big Button problem

Post by Synthiq » Tue Jun 30, 2020 4:33 pm

In this application the transistor type is hardly critical so a BC547B is fine.

ripvanwinkle
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Re: MP3 trigger and LMNC Big Button problem

Post by ripvanwinkle » Wed Jul 01, 2020 3:54 am

Thank you for the answer! I think it’s gonna work.

ripvanwinkle
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Re: MP3 trigger and LMNC Big Button problem

Post by ripvanwinkle » Sat Jul 04, 2020 9:24 am

Hi Synthiq, I added a transistor and resistor combination as you recommended and after some tests I find out, that the trigger input is kinda "numb" for ex. when I put a sequence, a trigger device only notice one signal of the ten. The sequencer sends a voltage between ~0.01 v and 0.03 v and the board receiving signal is Sparkfun mp3 trigger which as you said have active low inputs. The sequencer have now a PRO MICRO board due to other issues. So, do you think that the resistor value from 100kohm should be changed to a different one or should another hardvare solution may be added? I'm a little bit more better in soldering than programming but if the second option is better I may try it.

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Eloc
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Re: MP3 trigger and LMNC Big Button problem

Post by Eloc » Sat Jul 04, 2020 10:43 am

If I were you, I would try to test things individually to identify where the problem is. I would disconnect the sequencer from the MP3 Trigger device. I would connect a simple toggle switch to one of the MP3 triggers inputs and connect this to a confirmed 3.3V source on one side of the switch and ground on the other, and check that the device is consistently triggered by this switch (and whether it is active low or high). Then I would check the output of the Sequencer, either with a multimeter (if the output is slow enough), with an oscilloscope if you have one, or by connecting an LED with a suitable resistor (say 1K) as a simple visual aid. That way you can check the polarity and function of each thing to see where the problem lies.

Also if you do indeed need to invert the trigger, look up 'NPN transistor inverter' or 'NPN NOT Gate' to make sure that you've wired that up correctly. Really you need two resistors, one connected to the base from your sequencer, and one between the collector and V+ (3.3V)

ripvanwinkle
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Re: MP3 trigger and LMNC Big Button problem

Post by ripvanwinkle » Sat Jul 04, 2020 11:45 am

First of all thanks for reply. So I did most things as you mentioned above. Unfortunately I don't have an osciloscope but for both devices I installed LED's with 1k resistors. Both devices light up like crazy when I increase bpm, so I think signals are correct. Before npn inverter I tried adding 2M resistor and 100nf capacitor in pararell with zener diode and resistor for protection. This solution wroked really good until I increased speed - then I think this solution wasn't responsive enough for such a high speed. When it comes to the mp3 trigger itself - the device generally works by short to ground but I'm sure also can trigger by positive voltage -

"trigger inputs: Logic level 3.3V–5.0V, active low inputs, w/ internal pull-ups (connector provides individual grounds, allowing switches or jumpers to be connected directly to each trigger input)" - INFO FROM THE SITE (mp3 trigger board).

So for example when you push button you can trigger the sample and when you hold the button the sample start all overand so on. And besides all of that this trigger can react to rapid signals - i tried shorting cables very rapidly like a momentary switch would do and it works like it should be.

THANKS FOR INVESTING YOUR TIME IN THIS READING - that means a lot. I hope that my message is clear becaouse I'm not native and I can make some grammar mistakes and also if I'm asking easy questions - sorry I'm a beginner in all that stuff.

AND PS: If someone knows sparkfun's boards and all that stuff and you recommend me programming trigger board via 5v FTDI, I can try this but then I would want to be shure that this solution woulkd work.

fg
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Re: MP3 trigger and LMNC Big Button problem

Post by fg » Sat Jul 04, 2020 12:16 pm

did you try to reduce your capacitor to gain speed ?

ripvanwinkle
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Re: MP3 trigger and LMNC Big Button problem

Post by ripvanwinkle » Sat Jul 04, 2020 12:41 pm

When I first make the attempt to make capacitor with resistor in pararell I add a 10uf and 1M but this didn't work(mp3 trigger making sample start over and over without any signal from sequencer - like in scenario when I put jack directly to board). When I put 2M and 100nf everything started working except when I increase to fast bpm. Right now I'm going to make 2M and 10nf. Thanks, thiswhole pararell concept is most effective right now but I'm trying different methods also.

ripvanwinkle
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Re: MP3 trigger and LMNC Big Button problem

Post by ripvanwinkle » Sat Jul 04, 2020 1:18 pm

Ok right now I use 2M resistor and 10nf capacitor. I think now works like it should be. Thank you for helping me. When I'll put everything together and everything will be working as it should I let you know.

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