Introduction: Make an Automatic Plant Light

Picture of Make an Automatic Plant Light

This light helps your plants grow.

I got the idea from the Garduino, but nothing is taken from it. The schematic and the program are mine.

This plant light gives your plants 4 additional hours of light per day. When it gets dark, it turns on and after 4 hours of darkness, the light turns out. The light restarts when it detects light.

Step 1: Parts

Picture of Parts

You will need:

1x ATTiny26
1x 5V Wall adapter
3x Red LEDs
1x 30ohm resistor
1x 20 ohm resistor
1x 100kohm resistor
1x 50kohm resistor
1x power socket
1x power plug

plant container

Step 2: The Pot

Picture of The Pot

I used a plastic container and drilled two holes in the side. The wire goes inside those holes.
You should use some imagination and make one with the materials at hand.

Step 3: Electronics

Picture of Electronics

You can't see it on the schematic, but the + of the adapter goes to Vcc and the - to GND.
The plug helps to make the light more mobile.

Step 4: Software

You should already know, how to upload a program. I've uploaded the .c and .hex files.

In the source, the 14400 (in seconds = 4 hours) tells after how many seconds it automatically turns off. You can change this number if you want.

Step 5: Putting It Together

Picture of Putting It Together

I hot glued the board to the pot. The brown shielding on the top is to prevent the leds from turning themselves back off. That would lead to continuous blinking.

There's foam in the pot to provide a solid base for your plants. Maybe it's a better idea to use soil.

Step 6: Planting

Picture of Planting

Add some water into the pot. Try finding a plant, that loves a lot of light and put the seeds inside and leave it to grow.


chrwei (author)2009-03-12

add a solar panel and a battery and ditch the wall-wart for extra awesomeness

awang8 (author)chrwei2009-03-12

But then you'll need sun to shine on it and if the sun's shining on it then it's won't need growth lights... Not awesomeness... More like weirdness...

chrwei (author)awang82009-03-13

uh, sun shines during the day, charges battery, sun goes down, lights run off battery.... never seen a solar landscaping light?

awang8 (author)chrwei2009-03-17

The main purpose of this is to grow plants indoors. If you're taking it outdoors than it won't need growth lights because it's already exposed to the required spectrum for the required amout of time.

poiihy (author)awang82015-06-01

No, the purpose of this is to give plants 4 extra hours of light.

chrwei (author)awang82009-03-18

solar panels work inside too

awang8 (author)chrwei2009-03-21

Uhh... No they don't.

pullinsb (author)awang82009-03-26

Uhh... yes they do. Ever used a calculator with a solar panel on it? Most of the time a person will use them at their table/desk and not outside. Solar panels work inside because they turn light into electricity (hence the name photovoltaics). Of course the light would be more intense outside. Why not use this near a window, inside, where it gets the natural sunlight they crave and then your LEDs will give the extra 4hours. All in all, great i'ble.

nick_hunter (author)pullinsb2011-06-16

Indoor light also works on solar calculators.

DemonDomen (author)awang82009-03-23

Actually, the purpose of this project is to add 4 additional hours of light. The plant gets the natural amount of light plus 4.

awang8 (author)DemonDomen2009-03-23

But plants grow best with the natural amount of light. If you add more light it's not organic because the leafs are forcing the plant to take extra nutrients... Unneeded nutrients...

chrwei (author)awang82009-04-06

but a tomato growing in December can't get the the correct amount of natural light

awang8 (author)chrwei2009-04-07

Yes it can! It's summer in December!

DemonDomen (author)awang82009-05-03


awang8 (author)DemonDomen2009-06-07


Derin (author)awang82009-04-06

And if you grow a potato,then the plant will be a couch potato!

awang8 (author)Derin2009-04-07

Why not grow potatoes inside a couch-shaped container? Not a couch potato, a potato couch!

godfreyandthandi (author)chrwei2009-03-14

just use some capacitors?

Not as good as batteries.

Akin Yildiz (author)2014-04-29

hello DemonDomen, very smart design. what if you used a better light source... check out my design! we can add automatic watering too...

love & peace

ASCAS (author)2011-08-22

You do know that there is a cheaper and easier way to to this. I made a circuit that only uses 4 components.
1 - LDR
1 - NPN Transistor
1 - Resistor
1 - LED

DemonDomen (author)ASCAS2011-09-13

Your LED would glow all night, but mine turns off after 4 hours of darkness.

ASCAS (author)DemonDomen2011-09-14

oh so thats why you used a IC chip. You know that mosfets works good too :)))for a adjustable timer with a light sensor :))) other than that nice job :D

narendralkcrazy (author)2011-09-12

like this...

drgnflyz (author)2011-07-24

I am going to adapt this (along with the solar panel and battery) to give my chickens the extra 4 hours of light they need (inside their small coop) during the winter so that they will continue to lay eggs! Thank you for the instructable!

Zhelnot (author)2010-08-05

can u show me the sketches?

albylovesscience (author)2009-08-03

what are the plants growing ln

awang8 (author)2009-06-07

I'll be using this for my hydroponics system i'm going to set up one day... One day... I'll be making some heavy modifications. Basically, it means I won't be using a microcontroller. I'll use one of those power timer thingys and that also saves the hassle of running your wall-wart 24/7.

kanikedude03 (author)2009-04-23

can someone give me an example of the correct leds to use from mouser. They have so many different types of leds, and i'm not sure exactly what i need. Red LEDs is a bit general. haha

Jon316 (author)2009-04-26

the ATTiny26 dat your asking for is it a LM324 Quad Op Amp i saw dis one in radio shack and it looks like the one that is demonstrated in the pic

DemonDomen (author)Jon3162009-05-01

No. The ATTiny26 is a microcontroller, the LM324 is an amplifier.

awang8 (author)2009-03-06

Are you sure red LEDs are enough? I thought you're supposed to use a mixture of red, white, ultraviolet and infrared.

DemonDomen (author)awang82009-03-08

Red is included in white. I agree on the UV and IR part, but I'd have to buy the leds.

awang8 (author)DemonDomen2009-03-08

Oh wait, yeah. White has a mixture of all colours. Forgot.

Once someone told me you need green lights to grow plants. Totally disagree!

El Chucko Norris (author)awang82009-03-09

green lights are the worst the color of the plants reflects green light so they would die in only green light. red is best

Thanks for sorting this all out guys - i was going to ask if red LEDs were enough myself, but i've just read all this and now im sorted. cheers lads

awang8 (author)jamwaffles2009-03-12

In conclusion, red, blue, ultraviolet and infrared make a perfect greenhouse growth light.

jamwaffles (author)awang82009-03-13

w00t lol. is the infrared there for heat (whiche you dont get out of LEDs) or for the plant for some reason?

Derin (author)jamwaffles2009-04-06

The IR here is not the heat type of IR,it is the light type.

jamwaffles (author)Derin2009-04-07

aah right. i knew my physics teacher is really a loony :P thanks for clearing that up

awang8 (author)jamwaffles2009-03-17

Plant's absorb IR.

bdelanghe (author)awang82009-03-12

Red LED's should work great to supplement a little extra light. A few blue LEDs wouldn't hurt seeing as plants absorb that part of the spectrum. Green lights will do nothing. And IR and UV will actually damage the plants.

awang8 (author)bdelanghe2009-03-12

I disagree. Plants absorb UV and IR as well as blue and red. The sun naturally emits UV and IR and if it damages the plant then... Well... Your garden would be dead if that theory was true.

shamanwhitewolf (author)2009-03-13

Since we're using LEDs, I wonder if we can use a potato to power the light, thus feeding its own growth (still requiring nutrients, of course). Citrus and others could work also.

Not mine, but an example of bio-power:

eyalww (author)2009-03-12

SO COOL i'm so going to do this one... thanx!!!

headlessbubble (author)2009-03-11

sweet I want to try this

merseyless (author)2009-03-07

the simpler way to do this is with a transistor, light dependant resistor and a light emitting diode... but that doesn't have the added awesomeness of having to programme!

DemonDomen (author)merseyless2009-03-08

If you want, I can send you the schematic I made a while ago. I uses two transistors, a photoresistor and leds. The reason I used an AVR is that it is a lot easier and I can add the possibility, that the led turns off after 4 hours.

zaketus (author)2009-03-01

Is there a particular reason why you used red LEDs instead of for example white LEDs? Improvement idea: How about adding line or few of code to make it sense darkness instead of passing shadow? So when it senses "oh there's not much light" it'll keep measuring amount of light for 5-10s and if there is still dark -> turn on the leds. This way LEDs wont turn on for example when cat walks infront of the sensor. Anyway, great project.

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