Hello.
I need to controll a dimmer with 20 channels with a 0-10V analog signal. For this I need 20 analog output pins on my arduino.
Can I use the UNO for this? It has only 14 I/O pins, but topics say, that you can transform the analog input pins into output pins. Or do I have to use a bigger board (And if yes: which?)?
Also... Do I need to use a "filtering circuit" on the PWM pins as shown in this forum?
The Arduino has no analogue outputs. It has some PWM outputs but these are not analogue.
It is unusual for a controller to need an analogue input, are you sure this is what it needs and not a PWM input?
The answer to this question decides which of two solutions you need.
Please provide a link to your controller.
Maybe what the controller needs is 20 potentiometers? If so you could operate 20 digital potentiometers with an Arduino.
...R
Post the datasheet/product page for the dimmer in question please...
Grumpy_Mike:
It is unusual for a controller to need an analogue input, are you sure this is what it needs and not a PWM input?
The answer to this question decides which of two solutions you need.
The dimmer Uses a Analog 0-10V signal. 0-10 V lighting control - Wikipedia
Its a simple DC current which has a voltage between 0 and 10V, which is use to controll exacly one type of light. Our system has 4 areass which each 5 types of light (white,red,green,blue,yellow), so we need 20 outputs
MarkT:
Post the datasheet/product page for the dimmer in question please...
Well... There is non. Its a ,in a workshop, selfbuild dimmer. An Vrey Old one.
You will have to look for an external DAC. This one may not be too useful (just one DAC), but there will be with more outputs available.
As it's I2C you can add as many DACs on just two pins as they have unique addresses available. You'll be addressing them digitally (by writing a value to a register), and get an analog voltage out.
wvmarle:
You will have to look for an external DAC. This one may not be too useful (just one DAC), but there will be with more outputs available.
As it's I2C you can add as many DACs on just two pins as they have unique addresses available. You'll be addressing them digitally (by writing a value to a register), and get an analog voltage out.
A thing might be interesting: At the moment wo have the analog Dimmers and an old system, but in a few years, we might get a new dimmer which uses DMX.
Im primaly focused on controlling the old system, but also I want to take care of the newer Version.
Back to the toppic: So with this thing I could basically controll only 1 channel. I looked for versions with more channels, but couldnt find anything except this one. Also it would be good if the DAC would be small, no huge device. Are there maby shield. I searched, but couldnt find any good ones (I found one which 4 channel, which means i would have needed 5 of them.)
I found this huge list of DAC's, but dont know if they are that what I need
Okaghana:
I found this huge list of DAC's, but dont know if they are that what I need
It's quite easy to narrow it down. You want voltage output, not current, and lots of outputs.
Specs of LTC2668-16 seem to fit:: 16-bit resolution, 16 output channels (almost at your 20! Add a 4-channel one and you're at the 20 you want), 0V-10V output range, small (6x6 mm resp. 5x5 mm). May need some external components.
Is it important which bit version i order. (12 or 16)
Also: Do you have a photo of a thing like this. How big is it? Maybe an guide how you use these things?
Edit: Also there are different version in the shopping window.. whats the difference:
Okaghana:
Is it important which bit version i order. (12 or 16)
Also: Do you have a photo of a thing like this. How big is it? Maybe an guide how you use these things?Edit: Also there are different version in the shopping window.. whats the difference:
I hope you realise all I know is what's in that web site, I never used these chips.
For how to use them: read the spec sheet carefully.
For photo: you can quickly find some images of the package type in Google Images. It's a 6x6 mm QFNL package, maybe 0.5 mm thick - it's tiny. You put half a dozen of those on your finger nail. You may want to look for a breakout board for a QFNL package, or you'll likely have to design your own PCB.
Of course it matters which version you buy! Get the one you need. There may be a price difference, and as you can see in the specs the 12-bit version settles faster at the cost of having a lower resolution. Up to you what you want.
I bet there are more manufacturers that have similar devices around.
This is for a light dimmer? What kind of lights? Incandescent and led work fine with PWM and soft-PWM that a Nano should cover 20 lines without touching RX, TX, Led13 (Uno has 18 unused and RX, TX, LED13). Eyes are not so fast nor do filaments cool as quick as PWM at 500Hz to 1000Hz.
Some lights don't take to any kind of dimmer, not sure about CFL's or tubes or halogen bulbs.
Okaghana:
Is it important which bit version i order. (12 or 16)
Also: Do you have a photo of a thing like this. How big is it? Maybe an guide how you use these things?Edit: Also there are different version in the shopping window.. whats the difference:
You need 20 lines then how about 2 of the 12's?
Unless you can solder such small surface mount chips, you will need them mounted on breakout boards. Try eBay.
GoForSmoke:
You need 20 lines then how about 2 of the 12's?
He was asking about the 12-bit vs. 16-bit modules. They come in 1, 2, 4, 8 and 16 channel DAC. Not 12-channel. Hence my suggestion to look at 16+4 channels.
OP won't need any if the lights work on PWM.
I bet there are more manufacturers that have similar devices around
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Well... I found this one
OK: Here's what im going to do: Ill order an Arduino and test out if it will work without an dac as "GoForSmoke" has suggested. So far, im happy with the answeres i got.
What kind of lights or other things are you using the dimmer with? Some bulbs do NOT take PWM. The rest DO.
I want your project to succeed, we all do!
Arduino Nano has 2 more free pins than Uno. It can plug into a breadboard or female jumper ends slide onto the pins. While Uno has holes, Nano has pins which changes how you connect. You can solder to the pins but after that you won't get the pins clear of solder that oxidizes quickly leaving a poor contact on the pin. I bought DuPont cables with female ends just for adapters (my first was SD adapter) and boards like my Nano.
Check up on what to get before you buy so you get all the pieces you don't already have and they will fit.
I tried something stupid yesterday. I have 12V led disks that in one circuit only one is on at a time. I wanted both on all the time to see the brightness on the wall but when I wired them it was in series and for a while I was not thinking (aka being stupid) and couldn't figure out why I was not getting light.
It's very simple: 12V is not enough force to push through 2 12V led bulbs so no light.
When I changed the wires to parallel, both bulbs got 12V with enough mA to light both bright.
Stupid is a default state for humans. Thinking can change that, pretending to think does not.
AFAIK Nano has 2 extra pins but those can be used for analog read only! They cannot be used as general purpose IO, only input to ADC (or AC) MUX.
That stinks, you can't output on those pins at all. I found an explanation for why from John Wasser,
Some Arduino's have the surface-mount version of the ATmega328P which has two additional analog input pins (6 and 7). Those are ONLY for analog input and can't be used for digital I/O. They are only connected to the input multiplexer of the A/D converter.
With an Uno you would have to use RX and TX to get 20 pins which means no using Serial at the same time.
It is possible with an Uno though, or a Nano/Micro/Mini.
So you have 20 pins that must change twice every 2ms (ON then OFF time for PWM) each and something to say which change their duty cycles (brightness) just when. This is assuming that the lights may be different brightness, same would be easier.
GoForSmoke:
What kind of lights or other things are you using the dimmer with? Some bulbs do NOT take PWM. The rest DO.
Ok: We use a wild variety of Different lights. We use cans, fresnel, and other types, which all together use following bulbs: 75w Reflectors, 150/300w Halogen, par 300w and par 1000w.
Maybe the lights can use RWM, but I'm pretty sure the dimmer cant.
wvmarle:
There may be a price difference, and as you can see in the specs the 12-bit version settles faster at the cost of having a lower resolution. Up to you what you want
Lets say I want to have my brightness divided in 100 steps (I think for our system this is sufficient). Would I need only a 7bit board then?