HydroRed
Well-Known Member
This exactly. But the use of it as a fail safe "shutoff" rather than a temp contoled dimmer unit is a great idea & im sure would help some diy'ers sleep a little better at night.
BOBBY_G
Well-Known Member
go to 350 mA with those for identical effect
SSGrower
Well-Known Member
Alright, so staying in line with the whole managing of a microclimate and as @PurpleBuz wishes for us to use our brains.......
Rabbits hole here I come.....
Sunrise and Sunset by automated control via systems similar to those available from Titan are for certain the route to go in a professional, commercial, production oriented setting, which if I have not made clear by now is nowhere near here (see above reference to rabbits hole)
PWM pulses a signal in the millisecond or less frequency range, this signal then is used to "switch on and off" so fewer photons are generated vs. a straight reduction in current supplied to the cob which will still dim but as I understand can shift the color some.
It is certainly possible Titan or others have this very device but here is the kicker I desire to make it something that goes on the driver(s) I have (wtf you expect me to do with them throw them away?) that will automatically gradually increase either current or change the pulse to allow a gradual increase of light when the unit is first powered then when the light shuts off for the night a gradual decrease in current or change of pulse will dim it down. Since there is such little current draw (comparative to hps or mh) even if just one cob was set up this way temporarily driven by a ups of sorts would it atleast do a fair job of the simulation?
/...... Coming back out of the hole.....
ttystikk
Well-Known Member
I was trying to keep the light level constant and dim only when over temperature.
Airwalker16
Well-Known Member
Sorry didn't realize 72v chips were being used. Bobby g I right. Go with 350 ma.
Airwalker16
Well-Known Member
Just get a "B" version meanwell driver.
fjbudboy
Well-Known Member
I have those same type bulbs. Ime the diffuser was gel coated glass and the pcb radial. Not trying to say you are wrong as my floodlight type bulbs were as you say and most other could be that way as well.
I was thinking about this temp vs dimming pwm idea the other day myself. Using a raspberry pi with a temp probe to control pwm seems like you could do all sorts of stuff. Things like soft start, temp dimming, timer and ?. I dunno how though, but I'm pretty sure its possible.
SSGrower
Well-Known Member
not knowing jack about arduinos or raspberry pi id say I think its proven they can but I know the raspberry pi cant handle an abrupt shutdown without risk of corrupting the OS
ttystikk
Well-Known Member
Yes it could be done, without a doubt.
I think it can also be done with the dimming leads, a thermal sensor and a few other parts at minimal expense. No need to over complicate a thermal dimming circuit.
Abiqua
Well-Known Member
PWM color shift in some white led's is less than 3 steps of the MacAdam elipse...look at my post in the end of that thread...the color shift would be imperceptible to the naked eye....and dimming does NOT seem to create a color shift outside of the datasheet specs and maybe even less...both imperceptible to the naked eye. Now mono colors might have some shift .......green [iridium]......... red [Tj heat]....
Pwm is just pulsed light so quick that the human eye just thinks it is dimmer, but to the plant it may/may not be different...
Pwm is just pulsed light so quick that the human eye just thinks it is dimmer, but to the plant it may/may not be different...
SSGrower
Well-Known Member
I gotta think if I were living under a strobe light I'd be even more special...PWM color shift in some white led's is less than 3 steps of the MacAdam elipse...look at my post in the end of that thread...the color shift would be imperceptible to the naked eye....and dimming does NOT seem to create a color shift outside of the datasheet specs and maybe even less...both imperceptible to the naked eye. Now mono colors might have some shift .......green [iridium]......... red [Tj heat]....
Pwm is just pulsed light so quick that the human eye just thinks it is dimmer, but to the plant it may/may not be different...
I though 1 step on the McAdams was what is humanly perceptible. Much more info for me to absorb on this aspect, as seems more and more things in life
BOBBY_G
Well-Known Member
admittedly out of the loop on the current state of this thread, but is dimming even worth it considering the following:
-trend is to increase number of cobs and run them softer
-that results in less heat, in some cases so much less that its taking the plants out of the ideal temp range
-any array of N cobs can be dimmed in increments of 1/N by simple switching using cheapo temperature switches
-trend is to increase number of cobs and run them softer
-that results in less heat, in some cases so much less that its taking the plants out of the ideal temp range
-any array of N cobs can be dimmed in increments of 1/N by simple switching using cheapo temperature switches
Airwalker16
Well-Known Member
What is this 1 step, 2 step, 3 step, 4 step, 5 step binning I see on Cree's website? It seems that the only difference is the Letter in the part # at the end? What is it exactly?
ttystikk
Well-Known Member
Please elaborate?
BOBBY_G
Well-Known Member
in order of those above
1. obvious fact
2. is heat really so much of a problem that we need to overthink it (i.e controlling it via dimming?)
3. when i say switch off 1/N of the cobs, probably 1/N of the drivers would be more appropriate (well easier, at least)
lets say you have a space of 8 bars with 6 cobs each, each bar on its own 200W driver. at appropriate distance to canopy so that light is relatively uniform (no lenses)
at 85 degrees one of the drivers kicks off with a simple thermostatic switch, and you 'dimmed' from 1600W to 1400W
at 87 degrees you drop another driver and youre at 1200W, etc
as an extension of this build a simple circuit on a B version of the meanwell that uses a few fixed resistors in parallel, some of the relays are triggered by relays to change from 100% to 70% current.
the 'logic' in this case could be as simple as a cheap bimetal wall thermostat
1. obvious fact
2. is heat really so much of a problem that we need to overthink it (i.e controlling it via dimming?)
3. when i say switch off 1/N of the cobs, probably 1/N of the drivers would be more appropriate (well easier, at least)
lets say you have a space of 8 bars with 6 cobs each, each bar on its own 200W driver. at appropriate distance to canopy so that light is relatively uniform (no lenses)
at 85 degrees one of the drivers kicks off with a simple thermostatic switch, and you 'dimmed' from 1600W to 1400W
at 87 degrees you drop another driver and youre at 1200W, etc
as an extension of this build a simple circuit on a B version of the meanwell that uses a few fixed resistors in parallel, some of the relays are triggered by relays to change from 100% to 70% current.
the 'logic' in this case could be as simple as a cheap bimetal wall thermostat
ttystikk
Well-Known Member
I think we're talking about two different overheating situations. I'm being very specific about my desire to control excessive heat buildup in the fixture, at the COB itself, with the aim of protecting the equipment from overheating itself.
This can be the result of various causes, including the space overheating, but I'm looking for a way to control or eliminate the heat generated by the fixture by dimming it or shutting it down as needed, preferably automatically, without the need for a logic circuit.
Therefore, shutting down a chip at a time isn't a viable solution if they're all overheating; the ones left on will continue to overheat.
Dealing with overheating in a space is old hat; there are any number of thermal protection devices for spaces already on the market, just look up 'Chernobyl switch'. They work by being on a trigger cord and using a thermostat, shutting down the trigger cord if temps exceed a given limit.
Airwalker16
Well-Known Member
What is this and what's it for? Does that say Super Sprouter?