DMX-sensing Relay?
- Thread startermicrostar
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jtweigandt
Well-Known Member
Mac Hosehead
Well-Known Member
Seems like you can still buy stuff: http://northlightdmx.com/DMXtoRelay.htm
microstar
Well-Known Member
My use case:
I have two sources of DMX in a small theatre. A conventional 48-channel console with manual faders and a Fleenor PRE-10A remote preset panel.
All the lights are conventional, but I am going to install some DMX "strip lights" to light a cyc, which probably won't get used a whole lot. I don't want the cyc lights to be powered up 365 days a year and the breaker panel that supplies them is not convenient to get to so there needs to be a DMX-controlled AC power relay to turn them off without human intervention (or they won't get turned off).
I could devote one channel on the console to activate a standard DMX relay but that relies on a fader being left up (and I think we know someone will forget to do that).
Also, the DMX stream is still being sent from the console even if all faders are down. When power to the console is turned off (no DMX), the PRE-10A automatically comes on line. The same channel number on the console then has to be recorded into whatever scenes the cyc is used in on the PRE-10A. The "OFF" button on the PRE-10A does cleverly stop the DMX stream from that device.
So.... power could be automatically switched IF the relay device could sense when there was no longer a DMX stream from either controller, as the occupants would have to turn off all the stage/house lights at some point when they left the building.
I have two sources of DMX in a small theatre. A conventional 48-channel console with manual faders and a Fleenor PRE-10A remote preset panel.
All the lights are conventional, but I am going to install some DMX "strip lights" to light a cyc, which probably won't get used a whole lot. I don't want the cyc lights to be powered up 365 days a year and the breaker panel that supplies them is not convenient to get to so there needs to be a DMX-controlled AC power relay to turn them off without human intervention (or they won't get turned off).
I could devote one channel on the console to activate a standard DMX relay but that relies on a fader being left up (and I think we know someone will forget to do that).
Also, the DMX stream is still being sent from the console even if all faders are down. When power to the console is turned off (no DMX), the PRE-10A automatically comes on line. The same channel number on the console then has to be recorded into whatever scenes the cyc is used in on the PRE-10A. The "OFF" button on the PRE-10A does cleverly stop the DMX stream from that device.
So.... power could be automatically switched IF the relay device could sense when there was no longer a DMX stream from either controller, as the occupants would have to turn off all the stage/house lights at some point when they left the building.
microstar
Well-Known Member
I saw their website was still active a year or two ago after I found out the owner had died. Thinking someone had taken it over, I ordered some stuff. No communication and no merchandise. I should have called first but didn't. PayPal refunded my money.
microstar
Well-Known Member
Great info, thanks so much!
The Netron RP2 offers that and a TON more. Two relay channels. Power monitoring, auto scheduler, auto sequencer, True1 compatible connectors, and it's priced lower than CS Relay (though just $1 online price difference)
https://obsidiancontrol.com/rp2
https://obsidiancontrol.com/rp2
microstar
Well-Known Member
So in my quest to come up with a DMX-sensing relay by spending $500 in my labor vs. $296 for the ETC CSR-D unit, I have built the following light-sensing relay circuit
which turns on a relay when light hits the LDR (Light Dependent Resistor). It works quite well.
My idea is to use the classic DIY LED DMX tester circuit which uses two inverse LED's across pins 2 and 3 of the DMX line to provide the light to trigger the relay via the LDR. Thus the presence of DMX will trigger the relay.
The LED's do provide enough light to trigger the relay circuit when driven by the DMX signal. But, the LED's strobe or pulse in response to the DMX
and are dependent on the DMX rate and number of channels active (as they are designed to do!), which makes the relay chatter in response to the pulsing.
Any ideas on how to get around this problem other than spending the $296 of actual cash? Could a capacitor or inductor be used in either circuit to acceptably
slow down the pulsing for example?
which turns on a relay when light hits the LDR (Light Dependent Resistor). It works quite well.
My idea is to use the classic DIY LED DMX tester circuit which uses two inverse LED's across pins 2 and 3 of the DMX line to provide the light to trigger the relay via the LDR. Thus the presence of DMX will trigger the relay.
The LED's do provide enough light to trigger the relay circuit when driven by the DMX signal. But, the LED's strobe or pulse in response to the DMX
and are dependent on the DMX rate and number of channels active (as they are designed to do!), which makes the relay chatter in response to the pulsing.
Any ideas on how to get around this problem other than spending the $296 of actual cash? Could a capacitor or inductor be used in either circuit to acceptably
slow down the pulsing for example?
jtweigandt
Well-Known Member
Do tell... is that a page out of a Forest Mims Radio Shack book?
I think I still have one somewhere.
Chain the pulse that activates the relay to trigger a good ole 555 timer. The timer would switch everything off if not tickled before your pre determined interval.
Fun to cobble together, but I'm not sure I'd want to trust my show to MY work in this regard.. YMMV.
or use this as the sending signal from the booth to raise money to pay for the commercial solution
https://www.amazon.com/dp/B08VJ7KB85/?tag=controlbooth-20
I think I still have one somewhere.
Chain the pulse that activates the relay to trigger a good ole 555 timer. The timer would switch everything off if not tickled before your pre determined interval.
Fun to cobble together, but I'm not sure I'd want to trust my show to MY work in this regard.. YMMV.
or use this as the sending signal from the booth to raise money to pay for the commercial solution
https://www.amazon.com/dp/B08VJ7KB85/?tag=controlbooth-20
Last edited:
Mac Hosehead
Well-Known Member
jtweigandt
Well-Known Member
jtweigandt
Well-Known Member
You like the 555 or the coin op?
Mac Hosehead
Well-Known Member
Need a card reader version.You like the 555 or the coin op?
Here is a better way to add time delay to circuit:
microstar
Well-Known Member
microstar
Well-Known Member
I tried this and it didn't stop the chattering, BUT, I changed the capacitor to 10mfd and it seems to work great...very solid relay triggering.
Will continue testing with a different number of channels up at different levels to make sure it will perform consistently.
Then will have to take it from a breadboard to something more permanent; I've got some small generic pc boards.
Thank you very much for your help!
Mac Hosehead
Well-Known Member
Hah, it's good to know it works with 10mfd cap. Something else that should increase the time delay is adding a diode to the output of the the op-amp. As it is now, when the circuit is in the "off" state then the capacitor will discharge through both the transistor and the op-amp. Adding a diode should make it only discharge through the transistor and add to the delay.
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