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Topic: Control 230V dimmable bulbs (Read 1 time) previous topic - next topic

ktkt

Hello,

To complete a lightning project I'll need to control 3 circuits each with with different kind of dimmable bulbs, I've no major issues on programming, but what for interfacing Arduino with 3 independent 230V controllers ?

Thanks a lot.

Magician

Do you have a specification on controllers or link to ?


Grumpy_Mike

Basically you need to send some PWM signals out to the controllers. However, depending on what the controller needs you might have to put the PWM signal trough a transistor.

jackrae

3 off SSRs rated for logic level input.  Then drive them using PWM

marco180

I have the same problem with my project. I think you should use a high-voltage transistor, but i don't know which one. There are lots of different types of transistors, and i only know about low-voltage ones.

If somebody knows something about what type of transistor could we use... :~

jackrae

#5
May 03, 2011, 02:54 pm Last Edit: May 03, 2011, 03:02 pm by jackrae Reason: 1
On the basis that the lamps are 230 volt AC you cannot use a transistor - they are DC only.  For this application you would need a triac.  However, considering that one is working with lethal voltage levels and the skill or knowledge levels are minimal (or non-existant) then using SSR devices as the interface is the safest way to go.  These are relatively inexpensive (compared to either funeral costs or house rebuilding)

See the attached as an example.  
http://cgi.ebay.co.uk/Relay-3-Amp-SSR-Solid-State-RP1A23D3-Carlo-Gavazzi-NEW-/230614964838?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item35b1b91a66

E-bay sellers have lots of different rated units but the above is neat and possibly suitable for your application

SSRs have relatively slow turn-on  and turn-off characteristics so rather than using the fast Arduino PWM output you may have to create your own PWM signal with relatively low switching speeds.  Anything around 25Hz will not be noticable to the average human eye. 

Grumpy_Mike

The problem is that the SSR only can turn on every cycle so if you give them anything faster than the mains (50 or 60HZ) then it will be on all the time. Anything slower and there will be erratic flickering as there will be a beat between the PWM and the mains.
Some SSRs are meant to be dimmed, these are called phase angle controllers. You generate PWM and then smooth it so it is DC before applying it to the SSR input. Some SSRs require 10V so you need to pass the PWM through a transistor before smoothing it and applying it to the SSR.

(SSR - Solid State Relay)

ktkt

Do you have a specification on controllers or link to ?

Not yet and it's part of my issue as there are a lot available with diferent specs, nothing found specific for Arduino.

marco180

Thank you very much for the information. I didn't know anything about SSR (nor its existance). I've been searching something about these components and i found a lot with many different prices.

Does SSR operates like a normal (electromechanic) relay? If I generate a PWM signal, can i connect it directly to the SSR in order to take control of the output signal (AC)?

Sorry if my english level is bad. I hope you understand me.

Grumpy_Mike

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nothing found specific for Arduino.

No these devices are universal, most makers of them have never heard of the arduino.

Quote
Does SSR operates like a normal (electromechanic) relay?

No it uses a device called a Triac.

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If I generate a PWM signal, can i connect it directly to the SSR in order to take control of the output signal (AC)?

No. Only some SSRs have phase angle control. Then it needs the PWM filtering before feeding it into the SSR. See this link all about PWM:-
http://www.thebox.myzen.co.uk/Tutorial/PWM.html

Quote
Do you have a specification on controllers or link to ?

This link shows some:-
http://uk.farnell.com/jsp/search/browse.jsp;jsessionid=WAHSKPFBJVUQWCQLCIPZNFQ?N=0&Ntk=gensearch_001&Ntt=SSR+phase+angle&Ntx=mode+matchallpartial&suggestions=false&ref=globalsearch&_requestid=717784
They are expensive because they will handle a lot of current. There are cheaper devices that handle less current. Depending where you are in the world look at your local electronics distributor.

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