Seedling mister and led light bar

refriedbeano

refriedbeano

Active Member
Hey guys! I just finished designing a prototype and currently in the process of 3D printing/laser cutting everything together. I'm growing everything outdoors and wanted to make a system to grow seedlings in the shade in a cloche (https://www.amazon.com/dp/B09HDZ7ST9/?coliid=I36C8N35EUETCY&colid=3XYYO22BJZV3&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it). Its not as easy as you would think. First the top layer dries out relatively quickly. And I can't just throw it under the sun, so the seedlings get lanky. So I found some time to design this seedling light, which uses an arduino to control a mist pump and the led lights. The led lights will be run off of batteries and a small solar panel.
This is my first time growing plants under led lights. I just assume I won't need too many watts to keep the plants from getting lanky, I choose 3 watt leds, royal blue, and will have about 10 of them. For the misting system I bought some cheap misting nozzles and 3D printed a bunch of tubing connectors to route the water lines. I'm using a ball and socket design to guide the tubing/mister above the plants.
For the electronics, its just an arduino and 2 relays, with an rtc module (real time clock) to time out the misting/lighting events. I'm thinking of running the lights at a max of 20 watts for about 5 hours a day (more or less). Misting 3 times a day. Oh, and I will also be featuring a .91" OLED display and using a current sensor to keep track of whats going on when I'm away.
I should have everything ready by this weekend. I really like the look of the led's with the cheap lenses from amazon (https://www.amazon.com/gp/product/B0BR95HMGV/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1) I think I may have lucked out with this project.
 

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1212ham

Well-Known Member
refriedbeano said:
Hey guys! I just finished designing a prototype and currently in the process of 3D printing/laser cutting everything together. I'm growing everything outdoors and wanted to make a system to grow seedlings in the shade in a cloche (https://www.amazon.com/dp/B09HDZ7ST9/?coliid=I36C8N35EUETCY&colid=3XYYO22BJZV3&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it). Its not as easy as you would think. First the top layer dries out relatively quickly. And I can't just throw it under the sun, so the seedlings get lanky. So I found some time to design this seedling light, which uses an arduino to control a mist pump and the led lights. The led lights will be run off of batteries and a small solar panel.
This is my first time growing plants under led lights. I just assume I won't need too many watts to keep the plants from getting lanky, I choose 3 watt leds, royal blue, and will have about 10 of them. For the misting system I bought some cheap misting nozzles and 3D printed a bunch of tubing connectors to route the water lines. I'm using a ball and socket design to guide the tubing/mister above the plants.
For the electronics, its just an arduino and 2 relays, with an rtc module (real time clock) to time out the misting/lighting events. I'm thinking of running the lights at a max of 20 watts for about 5 hours a day (more or less). Misting 3 times a day. Oh, and I will also be featuring a .91" OLED display and using a current sensor to keep track of whats going on when I'm away.
I should have everything ready by this weekend. I really like the look of the led's with the cheap lenses from amazon (https://www.amazon.com/gp/product/B0BR95HMGV/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1) I think I may have lucked out with this project.
Click to expand...
Lenses are out of favor with LED. They just focus the light into narrower beams, not a good way to light a plant.
I suggest white light and off the self LED strips. Many of us built lights with these, Samsung and others. Then the light manufactures copied us.

27 watts for $8.40

 
refriedbeano

refriedbeano

Active Member
1212ham said:
Lenses are out of favor with LED. They just focus the light into narrower beams, not a good way to light a plant.
I suggest white light and off the self LED strips. Many of us built lights with these, Samsung and others. Then the light manufactures copied us.
Click to expand...
Thanks for the reply. I wanted to do this off the grid, and with just as many watts as i can get away with. So it has to be individual LED's spread out to cover the grow space. I am a little confused about whether I need the lenses or not. I'm just going to try this configuration out since I like the look of the lenses and it'll probably allow me to keep the lights higher up, so I can mist the plants better.
 
refriedbeano

refriedbeano

Active Member
I finally deployed the mister-light. I ended up going with just 2 misters because my pump is on the small side, but this prototype is just more of something I'm putting out there than something that is 100% workable. The big question is going to be, will 20 watts of blue light be enough to grow seedlings in the shade? I'm only running the lights for about 4 hours from 8pm to midnight.
Some more details of my setup: I'm using 10 3 watt leds with 5 in series, and putting 400mA through them. To control the led current I'm just limiting the voltage to 14.5, any higher than that and the current goes way up and they might burn out on me ( I burned a few out within just a few tens of seconds on 2 amps). The device is being run on 4S4P 18650 batteries, with a voltage range of 12-16. I plan on using a 20watt solar panel to keep them charged up, but I didn't really do any calculations just yet.
The electronics is just a real time clock (RTC), arduino, an INA3221 current/voltage sensor (but it didn't really prove too usefull), and a small OLED screen. The code was really simple- I just use the RTC to time the lights and the pump.
Tomorrow I'm going to plant my last two seeds of auto's. Its really a shame the ants killed all my seedlings a few weeks ago. I'm also going to plant some tobacco, which is the real reason I built the mister-light. I'm also thinking this will be good to start up a food growing program soon, with microgreens.
Of course I'm already planning the next design of the mister-light. Starting with the adjustable spray nozzles, going out the bottom instead of the side. And I'll need to get a larger, but still cheap pump. And also I want to add a few buttons to manually turn on and off the pump and light. Also, to drive the led's I'm looking into using lm317, which is a voltage regulator that can be used as a constant current device up to 400mA, but it will cost you about 3 watts in heat. But first I want to make sure this thing works, i.e. the seedlings don't get leggy in the shade.
 

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