Jump to content
AlanM

Interested in Apex/RK controlled d120's?

229 posts / 32867 viewsLast Reply

Recommended Posts

I'm working on a circuit to use an Arduino Uno and a digital potentiometer to allow an Apex to do dimming on a D120.  Is this something folks would be interested in?  Would cost about $40-50 for parts to control 6 channels of D120's, so 3 D120 units total.

 

Edit:  Would do this: 

 

http://arduino.cc/en/Tutorial/SPIDigitalPot

 

with the chip shown in that article.  Apparently the D120's use a 10k potentiometer to do the dimming, so the AD5206 has 6 channels of 10k resistors.

Edited by AlanM

Share this post


Link to post
Share on other sites

Well, the 5206 has 6 pots, 12 D120's have a total of 24 pots, so you'd need 4 of em and 4 arduino boards.  Wouldn't need that many channels on the apex though because those supply a voltage rather than a resistance.  Actually, maybe I'll take apart my D120 and see what voltage is across that pot to see if a voltage would just work.

Share this post


Link to post
Share on other sites

um, yes alan... i'd be VERY interested for my own lights and all those folks that has asked about them to have a solution to share.

 

that'd be great if you could figure it out and program the board accordingly. if you need some test items or a financial sponsor, let me know as i'd love to help you on this project!

Edited by monkiboy

Share this post


Link to post
Share on other sites

If the ReefKeeper Lite Plus has analog outputs it seems like it should work just fine.  This would just be replacing the knobs with a digital one that's addressable from an Arduino.  I'm going to do a little bit of teardown of my D120 to make sure the forum guys talking about attempting this know what they're talking about. 

 

I think it would involve de-soldering the pots from the D120, but maybe I could just put the ditigal pot in parallel with the knob and add a little socket to connect a controller.  Then you'd just turn on the knobs to minimum brightness and leave it there while the controller did the rest.  If you wanted it all the way off you'd have to switch off the socket it was connected to.

Share this post


Link to post
Share on other sites

some of the troubles that were found where shared power and wiring between the fans and the potentiometers. one would have to provide a new power supply for the fans as well. there's a couple hurdles that has prevented this from working in the past so i'm eager to see what you can do!

Share this post


Link to post
Share on other sites

right.  I have it open now, and I can see that the board the pot is connected to is a bit more complicated than just providing a dimming voltage.

Share this post


Link to post
Share on other sites

I'd be interested in working with you to make it work on the Reef Angel.  Happy to loan you equipment, assist, collaborate, etc. to make it successful.  LMK

 

Thx

 

Ross

Share this post


Link to post
Share on other sites

OK.  So here is the pic of the potentiometer board:

 

2895475d-04b7-48fa-90a9-386eb95003f0_zps

 

The pot is a 5-pin one which has an on off switch which are the two pins under the AMC and the 3 pins just over the surface mount resistors on the bottom vary the resistance.  I'd planned to replace that pot with a digital one.  It seems to be a 500k Ohm one.  But then I saw the VDIM+ and the VDIM- which I've labeled Pin1 and Pin2.  When the lights are on all the way dim I get 0.5V across those, when they're on all the way bright I get 9.8V across those. 

 

There are 4 wires coming out of this little board going into the driver which I think are vdim+, vdim-, fan, and ground.  I think if I just put a 0-10V signal on the first two pins from the Apex or ReefKeeper I could dim these things and leave the pot alone.  No arduino or digital pot needed. 

 

Marco, was there a place where people were trying to hack these things and ran into fan problems?  I could see a problem if it was actually running some current through these vdim+ and vdim- pins, but at least on mine the fan speed doesn't seem to vary with the dimmer knob.  I can at least put a little pot on a 9V battery to see if I can dim them that way so I don't risk drawing too much current from my Apex.

Share this post


Link to post
Share on other sites

Marco, was there a place where people were trying to hack these things and ran into fan problems?  I could see a problem if it was actually running some current through these vdim+ and vdim- pins, but at least on mine the fan speed doesn't seem to vary with the dimmer knob.  I can at least put a little pot on a 9V battery to see if I can dim them that way so I don't risk drawing too much current from my Apex.

yeah, but it was on the greensun units which use a non-resistance based driver and actually not come with 0-10v and then the ajm reef units which i think are the greensun rebranded/resold on the michiganreefers thread. then in conversations with evergrow engineers, they have been asking ME questions which seems very backwards as i'm not even 1/5 the technical person you sound to be and they should be. evergrow states they should have a solution in a month or so but they've been saying that for eight months so i eagerly await your results. let me know if i can help somehow or put you in contact with their engineering team once you have a solution or for information.

Share this post


Link to post
Share on other sites

Ok. Will try some stuff tomorrow. Will just twist in some wires for now and if it works will make a cleaner solution. That can be put back to factory config easier.

Share this post


Link to post
Share on other sites

I'll be keeping an eye on this, I could even get it to work with my old Aquacontroller and AquaSurf module I think.

 If this turns out it could work with older Aquacontrollers (i.e. AC3)...please do tell

Share this post


Link to post
Share on other sites

haha, well I let the magic smoke out of the little circuit board pictured above doing some testing with a battery.  Hmm.  I should be more careful.  Still playing with it.

Share this post


Link to post
Share on other sites

haha, well I let the magic smoke out of the little circuit board pictured above doing some testing with a battery.  Hmm.  I should be more careful.  Still playing with it.

haha, still good to go i presume?

Share this post


Link to post
Share on other sites

That channel still sort of works.  And I've got one from the other channel to be more careful with.  I'm pretty confident that I can figure it out, and once I figure it out I won't need this pot, so it should be fine.

Share this post


Link to post
Share on other sites

So I had my electronics engineer look at this problem a little while ago as I'm also interested in having my D120's controlled by an Apex.  There seem to be 2 issues:

 

1) separating the pot dimming functions from other functions such as fan and whatever else is going on with that board

2) converting a voltage into a resistance to replace the pot dimming functions

 

The first is the harder problem that requires a bit of reverse engineering (and probably loss of magic smoke :laugh: ).  The second is easier and will involves a couple of FETs like these: http://www.digikey.com/product-detail/en/H11F1SR2M/H11F1SR2MCT-ND/1794001

 

I have some schematics that can address the 2nd problem so if the first problem gets solved, let me know and we can work together!

Share this post


Link to post
Share on other sites

OK.  I think I know how the little circuit board with the pot works.  Or at least I think I do.  It actually uses a change in current to dim the driver.  I was measuring a 0-10V difference across the pinouts when dimming to 0 or to max power, but that was an Ohm's Law effect of what was happening with the current.  Took me a while to figure out why they needed a little transistor on that board (the tiny square black thing in the middle with V+ on top of it).

 

So it's not as easy as just supplying 0-10V on those two pins.  I'd have to supply a fixed current along there, which isn't so easy.  I'll pull the pot off the board, see what the rating is, and see if I can't drive it from a ditigal pot like I'd originally planned.

 

DaveS, I could be wrong, but I think it's easy to do number 1 above.  I snipped the two wires that control the dimming, the bottom two on the far right in my picture, and the light was happily on full bright and the fans were running. 

 

Replacing an a physical pot with a digital one won't necessarily work.  Sometimes the digital pot gets pissed if the loads connected to the output resistance pins are referenced to a way different voltage than the signal and control inputs to the digital pot chip.  That FET is probably a better way to do it than with a digital pot and arduino board etc.  Could do it on one chip if you got one that would give you the right input and output ranges.

Share this post


Link to post
Share on other sites

By the way, digital pot won't work either because it's a 500k Ohm pot, which doesn't exist as a digital one, so it would have to be something more exotic.

Share this post


Link to post
Share on other sites

Right. I think theyre probably doing something cheap and reliable, but just not something Im familiar with. Our electrical engineer here was puzzled by the circuit. Sent me home with more things to measure on the working one.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...