The $3 4 channel constant current LED DMX dimmer board ( giveback project )

Just a clarification question after some discussion with other members in chat.

Exactly what components will need to be added to the board to make them functional?
 
The 0.4V will be an internal reference. You just select the resistors so that the formula is true.
 
AAH said:
The 0.4V will be an internal reference. You just select the resistors so that the formula is true.
Click to expand...

I understand your second sentence ... but not the first! What is the internal reference? Something set in the firmware or what?
 
The internal reference of a Constant Current Regulator is set within the architecture of the chip. How it is produced isn't necessarily of a concern, so long as you know what it is to do the calculation.
These chips aren't like a PIC microchip, they won't require a firmware to be flashed.
 
Thanks for the offer MPH. I'll put my hand up for 20. Time will tell if I've ordered 20 too many or 200 too few. :)
 
Re: New home for the 34 project

mrpackethead said:
Hi, Firstly thank-you so much for you support of the 34 project. I never anticipated to have such huge success in such a short time. After some short consideration, i've decided to set up a dedicated forum for the 34 project. This is so that i we can get multiple threads going on this, ie, use cases, application notes, answer your questions, and run the 'co-op' from.

Please sigh up.. Of course the dialouge will continue at ACL, id encourage you you continue to use the ACL forum.. 34 just has its own new home over at December1, where it will be easier to look after. This is not an attempt to overthrow ACL, ACL has a special place, and will continue to be sucessful!
Click to expand...

I'm glad to see the sentiment for ACL, I wish the project well and in line with my open stance still encourage conversation to occur here at ACL.

Phil
 
Would love to sign up for the Dec 1 site, but it won't send me an activation email, and so it won't let me login.

Mark
 
mschell said:
Would love to sign up for the Dec 1 site, but it won't send me an activation email, and so it won't let me login.

Mark
Click to expand...


emails are going out, so maybe its been spam blocked..
 
Hi guys,

After having looked at Fasteddys diagram for the 44's, I'd just like to confirm a few things so I have it all right in my head.

I'd like to be able to run your standard Ray Wu style RGB strip, strings or modules. Is the 44CVA the right board for this? I was thinking mini trees or some sort or corro element.

I see that the boards can be stacked to make say a 48 channel 44CV stack or a 48 channel 44CC stack, is there some sort of order they need to go in for addressing purposes?

How is the DMX side of things hooked up? Cat cable?

Am I right in assuming that I simply feed the required DC supply into the board for whatever is being used, say 5V for the 5V strip?

Lastly, and yes I may sound somewhat retarded , but what can I do with the CC board? Well maybe a better way to ask that question is "what is everybody else using the CC board for?"

I can see the use for the CV boards, but all this constant voltage/current, amps, milliamps and all the other electronics stuff is doing my head in. At this rate I may have it partially understood by Christmas next year!

Thanks guys,

Nathan
 
OK I'll try and answer your questions the best I can

I'd like to be able to run your standard Ray Wu style RGB strip, strings or modules. Is the 44CVA the right board for this? I was thinking mini trees or some sort or corro element.

Thats what I plan to use here too. The CV boards as the pixels, modules and strip have built-in resistors to allow them to work on a certain voltage (i.e. 12 or 5V normally)

I see that the boards can be stacked to make say a 48 channel 44CV stack or a 48 channel 44CC stack, is there some sort of order they need to go in for addressing purposes?

Not really. The first element of the stack needs to be a C?A, i.e. a CVA or CCA as that is the Addressable item. It sets the first DMX address, and you can mix and match any of the CC and CV boards below it in whatever order you want depending on your need.

How is the DMX side of things hooked up? Cat cable?

By default there are no connectors, just connection points. Some see this as a disadvantage, but I see it as an advantage. If you want to provide power via the DMX cables then you can. If you have a seperate power supply, you can use that too. Use 3 pin DMX leads for the DMX - well you can add that, or if like me you use RJ45's then you can make a little lead up. It's up to you how you connect things, same as the outputs - you can use a terminal, hard wire (such as in an item), wire up a 2, 3, 4 or 5 pin plug to it and use that to connect to a light, set of lights or 4 individual lights.

Am I right in assuming that I simply feed the required DC supply into the board for whatever is being used, say 5V for the 5V strip?

Yes, I believe so, but there is a small issue with 5V at the moment in that the boards need 7V in to run. MPH is looking at bypassing the internal voltage regulator in the chip so we can feed 5V directly in. For 12V and above this bypass is not needed, and I'm not sure how the final point will be bridged yet as it was a rather late thing I pointed out to him and he had not realised some will want to run 5V gear off it. It will be a very minor update at most

Lastly, and yes I may sound somewhat retarded , but what can I do with the CC board? Well maybe a better way to ask that question is "what is everybody else using the CC board for?"

Initially, nothing here at all. Later on I want to find some stars, simialar to the Tuppet stars, but just the front, and I'll put a few 4 pin RGB (or seperate R G and B) LED's inside to light it up as a double sided star. Perfect for a small topper on a minitree, or to hang in a larger tree as a rather unique home-made item.

The CC's are a small use item here, but eventually I can see myself using more of them, probably in groups here and there around the yard.
 
CC's would be good for things like the Mighty Minis or perhaps the Rainbow Floods, where there are discrete LEDs on a board with inline resistors that could be bypassed, since the resistors were for constant voltage and meant to regulate the current.

On all the LED strips, modules, etc, there are resistors that CAN'T be bypassed, so that's why the CV's are appropriate for them.
 
mschell said:
CC's would be good for things like the Mighty Minis or perhaps the Rainbow Floods, where there are discrete LEDs on a board with inline resistors that could be bypassed, since the resistors were for constant voltage and meant to regulate the current.

On all the LED strips, modules, etc, there are resistors that CAN'T be bypassed, so that's why the CV's are appropriate for them.
Click to expand...

Actually, you can't use a CC source to drive the MM or RF because they have multiple paths of LEDs (two on the MM and six on the RF) - at least from the connectors going into it. You would need a CC for each path. For instance, on the MM, if you tried to drive it with a set 200mA (each path is 100mA) one of the paths could take more of the current than it can handle, blow the LEDs (or at least one) and then all the current would be pushed down the other path and blow those as well.
 
budude said:
Actually, you can't use a CC source to drive the MM or RF because they have multiple paths of LEDs (two on the MM and six on the RF) - at least from the connectors going into it. You would need a CC for each path. For instance, on the MM, if you tried to drive it with a set 200mA (each path is 100mA) one of the paths could take more of the current than it can handle, blow the LEDs (or at least one) and then all the current would be pushed down the other path and blow those as well.
Click to expand...

You can easily run parallel sections of series LED's from one CC source. The problem is if the LED's are badly mismatched then you could exceed the current rating of the LED's and shorten their life. In most real world setups, the led's will be matches within a few %. The issue becomes if you do lose a LED due to failure of a LED or just a bad cct, then you could overload the other set and hasten their failure too.

A way of minimising the chance of this happening is selecting a supply voltage close to the total Vf of the series LED's. i.e. 7 Green/Blue LED's or 10 red LED's run off 24V - they would not be massively overloaded if you just placed them across 24V minus the drop across the Voltage matching resistor. Yes they would be running overrated, but these are home-made setups, not mission or life critical situations. This change in lights is probably not easy to do to older lights, but would be perfectly adequate for new designs
 
You must log in or register to reply here.
Back
Top