Cheapest way for wireless DMX control of a 3 ch (1 RGB channel) portable item?

[taybrynn]

I've got a project going where I'm going to run a small number of RGB modules using a portable display item ... power by an onboard 12v LiON DC power pack. 

Thus far, its been working using a cheap 3ch RGB controller (located inside the portable display item) which I can then control using a wireless remote control.  This is cool, but I'd really like to be able to have the computer control these items and have them be "instantly in the show" when powered up and worn by my kids.

My question is: how would I take this to the next level and actually have DMX (?) control over these portable display items, using wireless DMX and some simple controller capable of controlling 1 (or more) RGB modules ?

I really just need to control each item as a single channel, but ideally as an RGB (3 channel) item.  A bonus would be the ability to control every module in the item, but thats not a requirement.

Any ideas / thoughts?  Am I missing something really obvious, because it seems like there is already something that could do this ... but ideally it would be done cheaply.

[chrisatpsu]

Lynx wireless txrx... one in transmit mode near the dongle and one in rx mode near your 3channel controller

[taybrynn]

Good idea and thanks!  

After doing some research (on other options) ... I think that is the most economical way to do this.

Especially since I will probably already have a lynx tx/rx out there in tx mode ...

That would leave me with just a tx/rx (per mobile display item) and put them in rx mode and pair them each
with a simple $8 3ch DMX controller.

Since I will only have a 12v LiON battery pack,  I need a way to power the 6v to the tx/rx as well.

Seems like I could go with a cheapo 6v battery pack like this?  Any idea how long 4 batteries would run the tx/rx ?
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There are also some rechargeable NiMH 6v batteries, mianly for RC and phones ... that might work.

[bcstuff]

I just curious why you would need to use 2 TX/RX?

Could you not use the TX/RX  you were planning to use in your display and then use a modified EX/RX as the receiver?

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Also, could you leave off the LEDs as people had mentioned modding for the wireless SSR4 DMX to reduce power draw?

Just some thoughts...

Brian

[chrisatpsu]

because he's powering a 3 channel dmx controller that runs on dc. the ssr4 would require a child to be hooked up to 120v AC.  may not be a good idea.

[rrowan]

The LE/RX won't work because the 3 channel dmx  controller is a sealed unit and it has no access to modified it like the SSR-4, MR-16, etc

Cheers

Rick R.

[taybrynn]

Thanks all.  Great advice as usual.

I think I'll go with the Lynx tx/rx solution.

Just wish I had bought a couple more tx/rx kits in COOP !!! 

[bcstuff]

Ok let me start with the statement: My understanding of electronics is limited...
I would like to better understand and maybe help taybrynn in the process.

Firs, by no means was I suggesting to use the ssr4 with AC 120 volts. It was only an example where LEDs were removed in an application to reduce power draw.

Ok now the Ex/RX when modified has 3 wires connecting it to something else (i.e. MR16, SSR4).

A voltage wire (6 volts I believe)
A ground wire
and connection to the where the RS485 chip socket (which is removed) pin 1 which is the Reciever Output.

Is this not DMX data across this one line?
 
Could you not feed this into the input side of the sealed 3 channel controller

I may not have a grasp of how things work, and don't mean to seem like I am hijacking taybrynn's thread, but just curious and trying to understand.

Brian

[n1ist]

DMX uses an electrical standard called RS485.  This uses two wires, where the voltage difference between the two wires signals a "0" or "1" (there's also a ground to for shielding and to keep common-mode voltages reasonable, but that's not part of the signalling).  This is what gets sent over the CAT5/RJ45 cables, or XLR for commercial DMX, and is what the TX/RX outputs.

Inside devices that listen to DMX, there's a chip (MAX485, SN75176, or similar) that converts this differential signalling to a logic level (one wire, 0 and 3V (or so) for "0" and "1") that the PIC or other processor wants.

The EX/RX skips the differential RS485 step, and outputs the logic level signal directly.  It's to simplify things and reduce cost; no need to take logic level, convert to differential, and back to logic level to go the few inches from EX/RX to DMX device.

Since your modules are sealed, and are expecting differential DMX, you can't use the EX/RX without adding the other parts to make it a TX/RX.

/mike

[bcstuff]

Ahh, Thanks for the clarification mike.

Makes sense now.

Brian

[chrisatpsu]

in theory it should work, but when connecting it to non lynx hardware, it hasnt been proven, and might not work.  for example, the led's needed to be removed to work with a ssr4 for when the transformer is maxed out.  as far as somone else's equipment, the transformer might be at the max for running a controller. taxing it with more mA requirements might make it just not work. as a better chance for success, the tx rx in receive mode (RX) would be a good choice for trying to get existing hardware to work. I don't atk people's views on here, so please don't take it as that. I was just giving an example of what the OP could use as a easy work around into his current design. I don't believe my examples are the only way, and I really do welcome other's ideas, as I would also learn from it.  Also by opening his 3 channel controller, it might void any warranty he might still have on it.

[rm357]

I'm just thinking out loud...

I've been wondering if the the firmware for the LE RX or TX/RX could be reprogrammed to output the 512 DMX channel stream as pixel-data and fed directly into the end of a smart string...  Theoretically you could control 170 nodes, but that would require power injection to keep from overloading the wiring.


RM

[taybrynn]

I will try this out and let you know if it works.  For now I need to build the second tx/rx ...