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Embbeded 12v dimmers?

hi all,

a very little money project…

does anyone knows if there is a manufacterer constructing low voltage dimmers in 12v ( power from 50w to 100w in 12v) and controllable in 0-10v ?

as those light units should be inside different moving structures on stage , moving all the time, no cable is possible…

i m thinking of 12v car battery, thats for power…

for signal, im wondering if there is no solution to receive by radio or wifi a dmx signal … without pc on board… and decode it to 0-10v… the idea is a max of 150 euros per unit to receivedata , transcieve it in 0-10v .

if any link, any experience, it will be grattefully received ;-)
(i m sure kalle is on hollidays, sounds its not the good period to ask this type of question…)

cheers
christoph

take a look at http://theatrewireless.com/?source=google&gclid=CO64-e-Z5ZQCFRSb1QodUi6uQQ

MANY thanks henny, a real interresting site.

starway is doing a wifi dmx sender-receiver for 115euros the starway DisD 512 HF ( not founded english links)…
so now just to search for economical dmx 12v-dimmers ( rc4 is a bit costy ) or 0-10vcommand dimmers with an economical dmx4all demultiplexor

There are some very cheap radio switches in tool shops (around 10euros) - you can switch on/off your power plug with i.e. lights.
Its done by radio and you could hack it, if you have time and motivation for it as there is a radio sender build in.
Once, I thought about trying it. For sure there are some DIY-sites in the web already done it.

i need to dim, frank. anyway thanks !

dmx transmitting: //for the thread ;-)
i had also a look on the wi d-pen, not really interresting, because they need to be feed in electricty by the dmx device…
stll searching for good analogic 12v dimmer in low cost…

Build your own.
0-10V PWM dimmer should be easy to find.
As it’s only 12V resistive load it should be even simpler.

In simple terms you want your 0-10V line hooked up to one pin of a comparator. To the other you want a sawtooth ramping from 10 to 0V
The output of that drives a FET or similar to switch the duty cycle of the bulb.

The timer could be a 555 or similar.

I attaches a simple patch to explain the theory. You would have to run a much faster timer in real live though.

PWM.v4p (3.9 kB)

not sure thats so easy with 100w in 12v load… but thanks ! ;-)

And why would it not be?

Whatever you end up using it will still use solid state components to do it.

I am no EE so I can’t get you stared with what components you should use but I do know there are many transistors that is 30A+ and that should be enough with proper cooling. But you will have to verify that.

hi david… another friend of mine just had said exactly the same advice as yours ;-) :

And why would it not be?

ok ok ok , i m not an ee, but this is the good challenge…

here is a more complete link for PWM dimmers, i know NOW it works good for dimming in 12V…

really thanks for your help !

cheers
christoph

The hard part would be ether getting the sawtooth to ramp from 10 to 0V or to get the 0-10V signal into the right range. IIRC most generators only use 1/2 or 1/3 of the voltage in amplitude. That is why you see R6 and R7. Or at least I think so.
Maybe searching for a simple sawtooth generator with the right range would be the simplest.

david_web, i m not at all form electronic world…

why would i need a sawtooth, on the schema I just need to input my demultiplexor instead of the 10k potentiometer

?

Me nether.

From what I understand. The sawtooth wave (that is made up of all those components before the comparator U1b) has an amplitude ranging between 1/3 and 2/3.
R6 and R7 puts VR1 into that range so it gives an voltage from 1/3 and 2/3 so it matches up correctly with the amplitude of the sawtooth wave.

If the above is correct you want to convert the 0-10V range to 4-8V range.
Should not be that hard.

best way: ask to a friend to create the adaptation on a beautifull paper… go and buy the requested material and solder it.
i prefer to solder than to try to adapt something i do not possess at all, and that can finish in a burning smoking thing …
;-)
thanks for your help david ! as this is completely chineese for me…
christoph

hi to all…

take a look also here

tinker.it dmx module

i don’t know if could be helpfull…

any way

ciao

alessandro

No problem.
I don’t understand it ether. I’m just good at guessing how it works.

I hope your friend can make it work.
It would be nice if you can post the finished circuit when you get it working.

What is your plan to send the wireless commands?

@david:
plans for data: starway DisD 512 HF dmx sender on stage connected to my data arriving on stage ( less troubles with faradet effects in theatre).
and starway DisD 512 HF in each moving decor and a demultiplexor…
the starway seems not to work really up to 150m.more around 70/80m
there is only 2 channels, and this may be a problem if there are a lot of other equipments around its frequency. but budget will be budget. this should be non sense to put the monney of RVE 6x2kw dimmers in an HF-strong-emetter …

@alessandro: thanks ! didn t know that people uses arduino like this ! but ( helas) to much costy :-(

cheers :-))))

karistouf, i’m planning on using 12V PWM based dimmers too. although i’m not restrained in using wifi or wired connections, my limited budget points in a wired direction, no problem with those wires ;)

still i need to address around 50 dimmers in the end. so far i thought this could be a job for the Wiring board i have lying around but i don’t see myself capable of porting the ArduinoFirmata node to Wiring without insights to the code architecture. at this stage i doubt that it would perform smooth enough anyway using Firmata, the GUI while patching becomes slightly unresponsive. i’d rather have a serial connection between Wiring and vvvv, having Wiring do the PWM part software based onboard, but coding that is completely beyond me. the Wiring website has some nice example using a simple MOSFET based circuit for switching 12V based loads, i assume it should work ok as a PWM based dimmer too.

another way solving this could be DMX, tho still i haven’t come up with an idea on what could dim 12V based loads (around 30-40W each) at the end of the DMX line.

what did you get done on this project?

hi patrick.
the project did’n show up.
But I was planning at the end to use arduino to control little dimmers with mosfet.
and ethernet shield + a bridge RJ45-Wifi.
i m planning to write an artnet lib for arduino if it doesnt exist.

hey christophe,
sounds like this could also be a solution for my project. if you don’t mind, let’s chat some more via skype about this? would be cool!

best, patrick

hi patrick, i will be back at home around monday. would be better to make a skype.
about talking to the arduino, yes i may help you.
have you got something about the technical/artistical aspect of your project to send me ? would be great to know wich option to decide if you have 50 units .