Anyone doing an arduino controller?

i got burnt there also then i got andrew's aleast his has a memory feature. now back to regulating power from the arduino to 10v pwm. i have my idea on how how to do it, but i need to know if the arduino's 5v output is constant and what draw can the pwm handle
jeff
 
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Not sure what you mean by "constant." It's ~500Hz 5v PWM (basically, it's 5v when on and 0v when off, but the REAL values for on and off can vary a bit based on supply voltage and load on the pin, etc.)

Any Arduino GPIO pin can source or sink 40mA max. If you need more than that, you can just use the pin to drive a transistor. That's what I'm doing on my ELN shield, but the transistor is switching 10v instead of 5v. I'm sure there are other ways to do it but that's what I'm working on. :)
 
I just saw on one of the forum that if we use the 10v PSU for the arduino then it can put out the 10v PWM to control the meanwell (P). Can anyone confirm this? I've not yet received the driver.
 
The Arduino itself only operates 5v (or 3.3v on some clone boards). The PWM will always only output that voltage (or something very close to it, depending on loads, etc.) when it's "on".

If someone is supplying 10v, they're probably talking about pre-regulator; not running the whole board at 10v. And, they're probably using a transistor on the output of a PWM pin to switch that "raw" 10v, which is then supplied to the driver. That's basically what I'm doing, but instead of relying on having a 10v source that's well regulated, my shield uses the Vin pin (which is upstream of the regulator) and has a 10v regulator to supply the signal for the ELNs. It's a VLDO regulator, so you can use anything above about 10.5v on Vin and it'll work. Arduino Duemilanove boards call for a "recommended" range of 7 - 12v input and a maximum limit of 20v, so you'd basically want to use 10.5 - 12v input.
 
I had another idea for that as well. Although I'm not using the 10v to power the arduino.

Couldn't you power the arduino with a 5v wall wart. Get a 10v reg and hook it up to your led power supply? It wouldn't be terribly efficient I guess, but you're only using it to drive a pwm signal. Than just use der_wille_zur_macht's transistor from the arduino to switch it. It adds another part, but keeps you down to 2 power supplies and adds in 1 extra part.
 
Andrew, it depends on the type of LED driver. The Meanwell ELN series are "all in one" in that they contain an AC/DC power supply and a dimmable constant current LED driver in one package. So we don't have access to the LEDs "power supply" to use for powering the external dimming circuitry. Hence we have to come up with the 10v source on our own.

Putting the 10v reg on the shield restricts the useful range of power supplies you can use for the Arduino, but it prevents you from needing a second supply - if you use something above 10.5v it can supply the Arduino's reg and the shield's reg.
 
I like that idea. My current power supply hums because I haven't put an optocoupler in yet.

I guess I've got more research to do.
 
Ahh. That's right. But if you power the arduino with 10v you can use a transistor.

The arduino turns the transistor on which is powered by your 10v power supply.
 
So even if we supply with 10v to power the board, the PWM signal is still output 5v?
Click to expand...

Yes. The PWM output from the chip is basically equivalent to the chip's Vcc. Since the default configuration on the Duemilanove board is to run the AVR at +5v, that's what the PWM pins put out. You have to keep in mind that EVERYTHING on the Duemilanove board (and nearly ALL compatibles) is "downstream" of the onboard voltage regulator, except the "Vin" pin (which connects directly to the power source you plug into the jack), and some of the power circuitry. In other words, other than the Vin pin, everything on the board is +5v.

The few exceptions to the above rule are the Arduino clones that are specifically designed to run at 3.3v.
 
vnguyen said:
This is what I saw on the arduino site:
http://www.arduino.cc/playground/Learning/WhatAdapter
So even if we supply with 10v to power the board, the PWM signal is still output 5v?
Click to expand...

yes. arduino has a built in voltage reg because the atmega chip runs on 5v.

all is not lost though. dwzm is trying to amplify the signal using a transistor, I tried using an op amp (which didn't work for me). we can also use ICs like digital pots which can regulate a higher voltage source based on input from the arduino. there are many ways to skin a cat
 
Thanks guys! Now I got stuck with this! Hopefully someone will come up with the easy solution as I don't know much about of this stuff and trying to learn here.
 
I wouldn't say stuck with it. I may actually take that route because they have the AC built in.

If I get time I'll put a schematic up of what dwzm is talking about.
 
eln_shield.gif


This is the schematic for the shield as I'm prototyping it. I have the components, and just got notice form the board house that the PCBs are shipped (from China, so it'll take a little while to get here).

Once it's fully tested I'll post the EAGLE project if others want to use it. (Releasing the EAGLE files under Creative Commons BY-SA 3.0).
 
hehe, or dwzm has it done already.

Right now I'm using lm317's with a mosfet that's switched by the arduino. It's not the best solution, but it's cheap and works well.
 
andrew1056 said:
hehe, or dwzm has it done already.

Right now I'm using lm317's with a mosfet that's switched by the arduino. It's not the best solution, but it's cheap and works well.
Click to expand...
I've seen someone using mosfet to control the LED but he's using the buckpuck (only need 5v instead of 10v).
 
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