Some PCB design ideas for DIY LDD-L driver based builds

[kegler]

Decided to try my hand at creating a PCB with EasyEDA.

I have a couple of these PWM generator boards. They are available on E-Bay from many sellers in China starting at about $3.50 (Use search terms "PWM Generator" on E-Bay).

This board works well as a PWM source with any of the LDD drivers. Just connect up one of the three PWM outputs to your driver , supply it with +5V and it works as expected.

But I wanted to make it more Plug 'N Play. And I need more than 3 channels for some of my projects. So I created a host PCB that will support two of these modules. Jacks for input power and the PWM outputs are added. Serial Communications to each module are brought out to a Terminal Block for future use (remote connection via either an Arduino w/Network shield or some other method using serial over Ethernet). There are two DC power jacks for use in daisy chaining power from this board to another board/device (such as an Arduino).

The schematic:

and the PCB:

Not a complicated circuit. Since low-cost PCBs are limited to 100mm x 100mm, that became the size. There's room to do more. Connections between the modules and the host are via 3 headers soldered to the bottom of each module and matching sockets on the host board (just like the Arduino/Shields do it).

I have not ordered the initial boards yet.

Comments/Suggestions?

 

[Lingwendil]

Neat idea, might be handy modules to have around for sure. Board looks good so far, although it's hard to tell at the resolution you posted. Maybe post it higher res? When you export the image there should be larger options or PDF even.

Oh- I think the boards are good to go! I've been running one with seven LDDs and an SCW since they came in and it has been flawless. I'll give them another lookover tonight hopefully, then I'll post up design files for the 8up LDD-H PCBs!

 

[Jonathan Troutt]

Id

Neat idea, might be handy modules to have around for sure. Board looks good so far, although it's hard to tell at the resolution you posted. Maybe post it higher res? When you export the image there should be larger options or PDF even.

Oh- I think the boards are good to go! I've been running one with seven LDDs and an SCW since they came in and it has been flawless. I'll give them another lookover tonight hopefully, then I'll post up design files for the 8up LDD-H PCBs!

i would be interested in seeing the ldd-h boards

 

[kegler]

Sorry. This should be better.

 

[Lingwendil]

Looks good. Only thing I might do if it wa mine would be to pull the ground pour further to the edge of the bottom of the board, that way the TRS stereo jacks have a bettter connection to the ground pin. Otherwise looks good, you could probably even fit some drivers on there if you wanted to

 

[kegler]

@Lingwendil

Yeah, the ground pour does tend to get in you way at times, so I have been taking the quick method (whatever my default snap is set to) when restoring it. The final version will have it in the proper place.

As for drivers - not on this particular PCB. As you know my focus is on indoor gardening (veggies) when the weather gets too cold up here at the end of the summer. For my main growing room I will be using 2, 3 maybe more 8up LDD-H boards. Six PWC channels should be enough for my use case. I want to stay modular in this room.

I need to use the LDD-H's as this will be a 48V system. I live in a rural area. Power outages during the winter months happen. I have a pair of 3000VA UPS setups that have 48V battery systems (also have an AC generator). My plans down the road are to be able to connect the lighting directly to the batteries avoiding the conversion loses when converting to/from AC. Also down the road is a solar array that will also be a 48V system.

And for a first board, I want to make sure the connecting headers are all properly spaced for the PWM modules. I am relying on manually measured dimensions - no guarantee they are accurate at this point. I have not found any drawings of this module.

Another requirement for this particular system is that it must have both local and remote control access, hence the bringing out the serial connections for each module. When I say remote access I am only talking about access from my LAN only, not the Internet - security is a concern there. Could do this with an Arduino but will need to use a Mega (with a network shield) as the Nano/Uno only have one serial connection, where as the Mega has four. The Mega will simply act as a web server with a limited command functionality ( get/set current light levels, turn-on/off all lights, etc.) The operational logic will reside on a control panel (written in Java) running on a virtual machine on my server (which runs 7/24).

And yes, I have been watching what Tim & John have been doing with their 16-channel system using the Wemos. If there is a better method available I will consider it. Otherwise its going to be a KISS system.

But I am receptive to doing other designs with them that do include drivers. Once I get my component library completed (on EasyEDA), this should be fairly easy to do. I think a 4up LDD-L PCB with a single PWM module (3 channels) on a 50 x 100mm board, and an 8up LDD-L PCB with dual PWM modules (6 channels) on a 100 x 100mm board are do-able.

- Eliminate the PWM jacks (not needed and they take up a lot of space).
- Eliminate the pull down jumper (but leave the resistor enabled via hardwire).
- Put in a 2x3 or 2X6 (depending on version) PWM Select header for each driver.
- Add a wide input range(7-36V) DC-DC converter for the 5V supply (I like the one John selected - the Murata 78SR-5. However this is a 1.5A output part but at about half the price of a SCW. Will have to check what the PWM module actually draws. But if the 5V is going to be made available externally then the 78SR-5 may be the best choice.)

This would create a simple all-in-one board.
- Plug in the needed drivers
- Plug in the PWM module(s)
- Configure the board (PWM Select)
- Connect the LED strings
- Plug in the power
- Done.

What do you think?

 

[Lingwendil]

8up LDD-H board design file is live- please look this over with a gerber viewer before you have any made, to verify that there are no mistakes... No warranty is implied, however I will help as best I can if you have issues. So far the board works as intended. I haven't found any issues with the first set I had made.

https://github.com/Lingwendil/LDD-L-driver-PCBs-for-Aquarium-LED-lighting

Feel free to use these as you need, and if you have extras please help out those in need by giving out surplus to spread the love.

I have been running a board successfully with seven drivers/one SCW for the last month without issues. It was easy to populate, easy to use, and a great option for lots of control in one board. I'm very pleased!

 

[Ligershark]

are you selling any boards?

 

[Lingwendil]

I could sell a couple of my spares, but I'm not looking to get into more than a few at this time, I just simply don't have the time. What I have is the PCBs but I would have to see if I have enough terminal blocks, pin headers, etc to populate a couple if you wanted them complete.

If anybody wants to have a handful made to sell I have no problem with that, however. I only ask that they don't change the file or remove my info.