Can I make this black box led apex dimmable?

[Michael Lane]

You are exactly correct on all of your assumptions. I saw that board 5v to 3.3v converter earlier in this thread and was thinking that was the solution. Looks like that little board is capable of up to 5 channels which is great. The only issue is trying to get it into my hands quickly. So basically I'll be going from the apex 0-10v to the stevesled 0-5v pwm converter to that little tiny 3.3v converter on the HV1-4 inputs. I just dont like the idea of stacking converters normally. Last thing is do I have to grab a true common ground at each converter

Forgot to mention - you do need a common ground everywhere.

 

[Lvgmman]

If you have resistors on hand, you could make a simple single direction level shifter using a voltage divider.

So didn't fully think this through. The level shifter board mentioned up higher needs a reference source on both sides. I can get a 3.3v source by setting the timer to 100% on power up but the 5v source is a different story. I need all 4 - 10v variable speed ports so that eliminates using one to get a constant 5v pwm signal from the Steve's led board. I have the parts here and tried just going from the Steve's led board to the driver which actually works but the light seems to flicker when it's anything below 100% on. I haven't spent a lot of time troubleshooting it yet so I may have an update later.

This diagram is a bit out of my understanding so if this question seems dumb I apologize. As I'm reading this the 1kHz is the 5v PWM signal then a 1k ohm resistor, capture the 3.3v signal here, line continues to a 2k ohm resistor that's connected to a ground? Also what wattage are we talking with these resistors?

So purely a practical wiring explanation

Apex 10v to Steve's led pwm converter to 1k ohm (1/2w?) Resistor to driver dimmer + with a 2k ohm resistor tied to the fixture ground?

 

[Lvgmman]

Ok I take it all back issue was I was starting the apex at 0v which was a fast way to tick the light off since minimum is .1v so it was wigging out when the timer was turning it on at the apex was turning it off. The ramp works with one variation when programming on the apex. You have to go from 1 to 60% on the ramp as that's the full range of 0.1v to 3.3v. I'm going to mess with it a little more but it appears to be working. As an FYI I asked Steve's led too and they said they use their board for 3.3v as well without much explanation but I figured the limitation would be on the ramp percentages which appears to be true (1-60% = .1v to 3.3v).

 

[oreo54]

PWM ramping doesn't work that way..
Output is usually either 3.3V or 5V (most common though 10V PWM is around)

roughly speaking the output is EITHER 3.3V or 0V (or below a threshold voltage) ..

Any change in voltage is just a metering average.. i.e @ 5V PWM and 50% duty cycle your meter would read ON average 2.5V..
PWM "output" to driver..this period is controlled by the timing chip on the little board which is set by the pot..
Now there are other things like doe the driver itself convert that to an analog voltage internally..but that is a different story..
basic R/C circuit or fancier..

Point is that a PWM output only has 2 states.. on (at a SET X voltage)/off (0 voltage)..

Another example..
https://jeelabs.org/2011/11/08/fixing-the-arduinos-pwm/

 

[Lvgmman]

I get that but metered at 59% from the apex is exactly 3.3v on my meter after the Steve's led board. The ballast doesn't seem to care about the actual pwm voltage it only seems to care if its between .1 and 3.3v. I get that it's still pulsing 5v but in this specific case the ballast doesn't seem to care.

 

[Lvgmman]

Delete

 

[oreo54]

Meter it at 100% (pure DC) and that is what the PWM output is..
any other voltages are unimportant..

I get that but metered at 59% from the apex is exactly 3.3v

Assuming linearity the 10V analog signal from the apex means it should output 5.9V (@ 59%) to steves board.
by the magic of electronics this should output from Steves board either a 3.3V @ 59% duty cycle or 5V @ 59% duty cycle..

IF your meter averages ( a few can do Max voltage which would mean it registers 3.3V regardless of duty cycle
which may be what you are seeing)
then @5V it would look like 2.95V to the meter
@ 3.3V it would look like 1.95V.. or roughly..not sure of the exact conversion here..

Same w/ the driver IF it outputs PWM in proportion to the PWM signal.
A driver outputting, say 32V at 100% will look like it's outputting 16V at 50% dim.. but it's not..


If the driver can handle a range of PWM voltages it doesn't matter
50% at 5V PWM should be equal output on the driver as 50% of 3.3V (PWM) or X volts in the range of acceptance to the driver..

At least as I understand this..

Example of driver output w/ 50% PWM signal from a controller..

Point,, again, is generally there are no "in between" voltages except at the analog out of the Apex..
THERE are different types of drivers though that might change current vs changing duty cycle but increasingly uncommon.. I believe..


Hmm I guess some drivers do smooth out the DC voltage at the driver to LED end (assuming something like a R/C cicuit on the output). Not sure this is very common anymore either..