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1  Using Arduino / Audio / loop single sound on the WTV020-SD-16P on: July 04, 2013, 07:53:20 am
I have been playing around a bit with this sound module, both in standalone mode and using the-rebel-agent´s library.http://forum.arduino.cc/index.php?topic=117009.0

I am trying to figure out a way to retrigger the playback of a sound when it´s finished, to loop a single sound (I am aware it will not loop perfectly, I am mainly interested in just repeating the sound).
One way that works is using the asyncPlayVoice with a delay that corresponds to the sound length, but I was hoping to have a more general code that works with any sound without having to specify the length.
I tried using playVoice (which plays the sound to the end before moving on in the code) and then check the busyPin. When the playVoice has finished, I detect the pin to be low, but I am not able to retrigger any sound either using the asyncPlayVoice or the playVoice command. I also tried with reset first, but nothing happens. I added a serialcheck so I know that the code is checking the pinstate and detecting that it´s low.

Also, is there any way of looping a single sound when using the module without arduino? I assume it´s only possible to use the next/prev control?

2  Using Arduino / LEDs and Multiplexing / Re: buckpuck and tlc5940 on: August 30, 2012, 07:01:41 am
Have you connected the Ref pin of the buckpuck to +5v? (Assuming this is the buck puck: http://www.luxdrive.com/content/3021-BuckPuck.pdf)
I tried it, and it doesn´t work.
The vref out is mainly used together with a switch or potentiometer, as it only outputs 20mA.

Do you have this working on your end?

Often constant current drivers cannot pull down as far as a transistor.  I have had similar problems with the M5451 chip.  Check out the TLC5940 datasheet (or test it with a multimeter) to see how far it can pull.  If it cannot pull down far enough it won't register as a logic 0.  A solution is to feed the TLC into the base of a PNP transistor to get a hard pull down.
I am probably misunderstanding something, but since I am able to dim normal LEDs, as well as powerLEDs (using a circuit based on the LM317 chip which also uses a pull-up resistor), I would expect it to be able to pull down far enough?
3  Using Arduino / LEDs and Multiplexing / Re: buckpuck and tlc5940 on: August 29, 2012, 10:22:43 am
I hook it up as in the image from https://code.google.com/p/tlc5940arduino/
I have replaced the 2k resistor with the 68 k resistor, one of the outputs from the tlc goes to the ctl-in of the buckpuck, as well as through the 10k resistor to +5v. vin and vout on the buckpuck connected to an external power supply, led+ and led - to the led, common ground between tlc and buckpuck (either led - or vin, doesnt seem to make a difference).

hc
4  Using Arduino / LEDs and Multiplexing / Re: buckpuck and tlc5940 on: August 29, 2012, 08:04:58 am
Changing the value of the iref resistor didn´t help unfortunately. The powerled connected to the buckpuck stays on the whole time, while the other 5mm leds connected directly to the tlc outputs work as expected (using the basic use example).

hc
5  Using Arduino / LEDs and Multiplexing / Re: buckpuck and tlc5940 on: August 28, 2012, 04:19:07 pm
thanks for the answer!
I already had a 10k pullup resistor, but had a very different value for the iref, 2k, which I used for a different project. I will try the value you suggested and see if I have better luck with it then.

hc
6  Using Arduino / LEDs and Multiplexing / buckpuck and tlc5940 on: August 27, 2012, 04:05:58 am
Hi,
I have some buckpucks (3023) which I ideally would like to control with the tlc5940. It works fine with arduino pwm output to the ctl input of the buckpuck, so I assumed it would be quite easy to get it to work with the tlc5940 outputs as well, but so far no luck.

Anybody on the forum with experience with this combination?

best,
hc
7  Using Arduino / LEDs and Multiplexing / Re: TLC5940 p-channel mosfet dimming curve on: November 23, 2011, 02:04:48 pm
I just wanted to confirm that the last sketch I linked to (using the 2nd circuit without the zener) works fine when controlled from an arduino.
My components
3w white led (700mA)
q1 small npn transistor 2N5088BU
q2 powerfet n-channel FQP50N06L
r1 100k
r3 .75 ohm 2w

From the description at Instructables:
"
- Q2 (a power NFET) is used as a variable resistor. Q2 starts out turned on by R1.

- Q1 (a small NPN) is used as an over-current sensing switch, and R3 is the "sense resistor" or "set resistor" that triggers Q1 when too much current is flowing.

- The main current flow is through the LED's, through Q2, and through R3. When too much current flows through R3, Q1 will start to turn on, which starts turning off Q2. Turning off Q2 reduces the current through the LED's and R3. So we've created a "feedback loop", which continuously monitors the LED current and keeps it exactly at the set point at all times. transistors are clever, huh!

- R1 has high resistance, so that when Q1 starts turning on, it easily overpowers R1.

- The result is that Q2 acts like a resistor, and its resistance is always perfectly set to keep the LED current correct. Any excess power is burned in Q2. Thus for maximum efficiency, we want to configure our LED string so that it is close to the power supply voltage. It will work fine if we don't do this, we'll just waste power. this is really the only downside of this circuit compared to a step-down switching regulator!"

The benefits of porting this to the TLC5940 is higher resolution (4095 steps vs 255) and a lot of channels running from a single arduino.

So, anybody up for the challenge of modifying this for the tlc5940?
I only assume this would involve a p-channel mosfet, but I am not clever enough to figure this out by myself.
 
8  Using Arduino / LEDs and Multiplexing / Re: TLC5940 p-channel mosfet dimming curve on: November 23, 2011, 01:05:33 pm
So what you are implying is that all the simpler solutions, like the one below, are flawed solutions?
http://www.instructables.com/id/Circuits-for-using-High-Power-LED-s/step8/a-little-micro-makes-all-the-difference/

I would have liked to see a version of the above instructable adapted for the tlc5940.
9  Using Arduino / LEDs and Multiplexing / Re: TLC5940 p-channel mosfet dimming curve on: November 23, 2011, 12:20:25 pm
If somebody on the forum has made something similar to what Mike describes, it would be great if they could share their circuit.

There are so many posts describing bits and pieces of a circuit, but it´s hard to know if it actually works before someone has designed, built and tested the complete circuit.
10  Using Arduino / LEDs and Multiplexing / Re: TLC5940 p-channel mosfet dimming curve on: November 23, 2011, 12:10:59 pm
the tip 122 is a NPN resistor
11  Using Arduino / LEDs and Multiplexing / Re: TLC5940 p-channel mosfet dimming curve on: November 23, 2011, 12:00:02 pm
If I don´t remember wrong you trashed my LM317 circuit as well, and that has been working pretty good for two years  smiley

The strange thing about my new circuit is that no components get particularly hot even after leaving the led on full for 10 minutes, I still haven´t fried any leds, it worked with +5v (the old one needed +9 because of the voltage drop from the LM317), and the only thing I am unhappy about is the dimming curve. Oh well.

I would love to get constructive criticism/suggestions for improvement/simplification of my old circuit, so here is a simplified diagram (hope this one is drawn correctly) of that one.

and you can check out an image of the actual dimmer here (actually two connected together for a total of 32 channels):
http://www.flickr.com/photos/hcgilje/3945006625/in/set-72157622330769436

Both the transistors and the voltage regulators got pretty hot in this setup (the board is resting on two long heatsinks for the LM317s), and a few channels have died, maybe because I should have used resistors with higher effect?

12  Using Arduino / LEDs and Multiplexing / Re: TLC5940 p-channel mosfet dimming curve on: November 23, 2011, 11:22:21 am
For the record, here is the corrected schematic:

13  Using Arduino / LEDs and Multiplexing / Re: TLC5940 p-channel mosfet dimming curve on: November 23, 2011, 11:17:43 am
excuse my omnigraffle sloppiness. The LED is connected the right way.

I don´t see how my circuit is different from this one here (from Odisej), which is also based on 3w leds :

http://arduino.cc/forum/index.php/topic,52672.0.html

I would love to see the definite power led circuit for the tlc5940.

The inverted values is not a big problem, no, but it would be great to know that I have a circuit that get´s the maximum out of my leds.

hc



14  Using Arduino / LEDs and Multiplexing / TLC5940 p-channel mosfet dimming curve on: November 23, 2011, 09:49:49 am
I´ve made a circuit using a tlc5940 and a p-channel mosfet to control a 3W powerled.
This is the circuit:


It works, but has one big problem: the dimming curve makes it more or less useless for my purposes of slowly fading in and out the light.

Two years ago I made a similar circuit based on the LM317 and a transistor, which worked quite ok, but which wasn´t very power-efficient and had the problem of the inverted output (4095 off, 0 on). This circuit made perfect fades though.

To illustrate, when using the p-ch mosfet circuit, changing from 1 to 2 (in the 4095 range) makes the light incredibly much brighter than 1. This would correspond to maybe about 50 steps using my old circuit.

I have tried with four different mosfets, giving more or less the same result (irf5305,irf9z24n,irf9510,irf9610).

So, is this an expected effect of using a p-channel mosfet or is there something I can do with my circuit to improve this?

hc
15  Using Arduino / Networking, Protocols, and Devices / Re: hooking a midi nano kontroller to arduino on: March 18, 2011, 11:06:27 am
I guess my attempt was slightly optimistic. After more googling I came across an article on Make which explains how to this:
http://blog.makezine.com/archive/2010/11/usbhacking.html
Basically I need a usb host shield, so I just placed an order on Circuits@home:
http://www.circuitsathome.com/products-page/arduino-shields/usb-host-shield-2-0-for-arduino/
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