Back from the shelf and new prototype coming up

A project log for MoAgriS: Modular Agriculture System

Growing food crops and other plants in small indoor spaces using established containers like regular plant pots and very little money.

Prof. FartsparkleProf. Fartsparkle 12/20/2018 at 13:090 Comments

I had to put the project aside for the past 6 months, unfortunately, due to a high workload at the office and a long vacation in-between.

In the past few weeks I got more and more requests from friends and strangers if I could help them re-create at least the basic lighting setup to start growing food plants in doors. That gave me motivation to dive back into it.

Even better LCSC approached me a few weeks ago to help me out with components and PCBs.

This was a great fit as the main LED driver (PT4115) is from a Chinese producer and hard to get from trust-able western distributors. LCSC is one of the few reliable source that stock it. Getting all the other jellybean components from LCSC instead of AliExpress make the repeat-ability a lot better as well, its actually not that easy, with a reasonably long BOM, to get all the exact same components again from AliExpress as a lot of vendors just sell generic stock and tend to change manufacturers if one can't deliver for a while.
Here is the full BOM if anyone is interested:

Given that I don't have to order every components in fixed multiples made the actual per piece cost a lot cheaper as well.
So thats nice. If that new design proves to be successful I may sell a few kits in the future if enough people are interested.

Here a render of the new LED board design.

During my testing in the summer I tried out various configuration. 2x3W, 2x5W, 2x1W. Anything larger than 1W was dying after a few weeks even with heatsinks attached directly to the heatsink pad of the LED.
1W LEDs work alright but the light output is a little too small so I went back and added a third LED to the module and made it slightly larger.
With 2oz copper boards I'm fairly confident to keep the LEDs well below their max temp. specs.

I also tested  the communication via SDI-12 over the single wire and had great success with that.

I will post my test results once the boards and components arrive and I had the time to solder them up. Which will probably happen in the first week of January, until then I'm busy attending 35C3. I will be at the Hackaday assembly if anyone want to say hi.

You can find the new design files in my GitHub repo: