Introduction: Solar Shrub

I'm a solar energy advocate, tinkerer, and enthusiast, but let's face it; solar panels are ugly!

Flat, rectangular panels can only be arranged in so many ways and always look industrial, boring, and out of place. So I decided to build a functional, but more aesthetically pleasing version of a USB solar charger.

I call my creation the "Solar Shrub". It's designed to resemble a round-leafed plant in a flower pot, but unlike a real plant, this one can charge my iPod, iPhone, and any other USB chargeable device!

I used eight 1.5 Volt round solar cells (leaves) attached to shrink-wrapped wires and clothes hangers (stems) to create an array capable of producing 5 Volts at about 300mA. I wired two sets of four cells in series (to get the voltage) and then wired the two arrays together in parallel (to get the current). I stabilized the power by building a 5 Volt Regulator circuit, then added an on/off switch, power LED, and female USB connector.

Now you can build one too! Just follow these instructions, then put it in sunlight, flip the toggle switch, and plug in your favorite USB device!

Step 1: Materials and Tools Used

Materials for Power Circuit:

1 - 7805 Voltage Regulator (Radio Shack #276-1770)
1 - Heat sink for the 7805 (Radio Shack #276-1368)
1 - Hea sink mounting hardware(Radio Shack #276-1373)
1 - Red LED(Radio Shack #276-041)
1 - SPST mini toggle switch(Radio Shack #275-0324)
1 - 22uf capacitor(Radio Shack #272-1026)
1 - .01uf capacitor(Radio Shack #272-1065)
1 - 220 ohm resistor(Radio Shack #271-1313)
1 - 4.7k ohm resistor(Radio Shack #271-1124)
1 - 3.3k ohm resistor(Radio Shack #271-1122)
1 - USB extension cable (Male to Female)
1 - Blocking Diode (1N4001)(Radio Shack #276-1101)
1 - Round Proto Board (Radio Shack #276-004)

Materials for Leaves and Stems:

8 - Round solar cells (hacked from solar garden lights) (Lowe's #379421)
8 - Wire clothes hangers
1 - Roll each of red and black 22 AWG wire (Radio Shack #278-1224)
2 - Pkgs of assorted shrink wrap (Radio Shack #278-1610)
10 - Small wire ties
1 -  Can green spray paint

Misc Materials:

1 - 6" Clay Plastic Self-Watering flower pot (Lowe's #285869)
2 - Metal angle brackets
1 - CD
2 - Plastic standoffs(Radio Shack #276-1381)

Tools:

Soldering Iron
Solder
Wire strippers
Side cutters
Dremel

Step 2: Building the Power Circuit

Most USB devices will charge with 5 Volts and ground delivered on the red and black wires of the USB connector. As I learned from Adafruit's wonderful video at (http://www.adafruit.com/blog/2010/08/03/the-mysteries-of-apple-device-charging-video/), Apple devices won't. You have to trick them by providing specific voltages on the other two wires. In this case, I'm sending approximately 2 Volts on the green and yellow data wires.

I used a round proto board to go with the round theme of the project, but you can just as easily use a square, boring board. I also decided to use jumper wires for the switch and LED so I could easily disconnect them from the circuit board after they were mounted to the flower pot. (What a strange sounding sentence.) You could just as easily hard-wire them to the board.

The circuit is a simple one based on the 7805 5 Volt Regulator with supporting components and a voltage divider to supply the 2 Volts mentioned above.

Assembly:

1. Solder the red wire (this will eventually connect to the positive terminal of the cell array) to the circuit board and to one side of a double-pin plug (for the power switch).
2. Solder in another double-pin plug for the LED and attach it to the open pin of the first plug.
3. Solder in the 220 ohm resistor, which connects the LED plug to ground.
4. Solder in the two capacitors. C1 is polarized so be sure to configure it correctly.
5. Solder in the voltage regulator.
6. Solder in the two resistors, which make up the voltage divider circuit.
7. Cut the USB cable about 6-8 inches from the female end and strip away the insulation and shielding
8. Attach the four wires of the USB cable to the circuit board.
9. Attach the black (GND) wire and create a "ground bus" across the back of the circuit board to link all components.
10. Solder jumper wires w/ female connectors to the switch and LED. Remember to slide some shrink wrap onto the wires before soldering. I've found it's really hard to get it on there afterward!
11. Test the circuit. I like to test things as I go along instead of waiting until the thing is all together. So I attached a 9 Volt battery to the red and black wires and tested the circuit with my iPod. Success!!!

Step 3: Assembling the Base

The base of the Solar Shrub is, of course, a flower pot. I drilled holes for the switch and LED and cut out a slot for the female USB connector. In order to attach the USB connector to the base, I built a mount using a couple of angle brackets, some double-sided tape, and a tie wrap.  I added 2 holes to the base to accommodate the nuts and bolts that hold the connector into place.

I wanted the electronics to be somewhat protected from the elements so I decided to use a CD as kind of a false floor. I mounted the circuit board (upside down) to the bottom of the CD using plastic standoffs. The red and black wire that connect the circuit board to the solar array pass through the center hole of the CD. I also added felt strips around the base to support the CD.

I drilled two more holes in the CD so I could later mount the leaves and stems to the top of it.

Step 4: Hacking the Garden Lights

The next step is to extract the solar cells from the garden lights. I found that most solar garden lights at my local retailers had square cells. I had to look around quite a bit to find round ones. I bought these at Lowes for around $3.25 each.

They were pretty easy to disassemble:

1. Remove the battery
2. Take out three screws
3. Cut a few wires
4. Pry the cells loose from underneath.

I did this 8 times, of course.

I tested each cell under load to make sure it provided approximately 1.5 Volts.

Step 5: Building the Leaves and Stems

I cut various lengths of red and black wire between 6" and 10" and soldered them onto the 8 cells. Then, I slid 3.0mm shrink wrap over the wires and pushed in a length of clothes hanger wire to reinforce the stems. Once I had all 8 stems together, I spray painted them a nice shade of green (being careful to avoid the tops of the cells).

Step 6: Attaching Stems to the Base

The self-watering flower pot came with a plastic insert that has holes which are spaced out perfectly for the Solar Shrub. So I bent the end of each stem, about an inch from the bottom, to 90 degrees and pushed them through the holes. Then I tie wrapped the hanger ends together to separate and stabilize them.

After I had all of the stems mounted, I wired the cells together in a series-parallel circuit as shown in the schematic. Then, I added a blocking diode to the positive (red) lead. This prevents reverse current through the cells when there is no sun light.

Step 7: Putting It All Together

The last steps are to connect the output wires from the solar array to the red and black power leads on the circuit board, mount the plastic insert to the top of the CD (using 6/32 screws and nuts) and then take the Solar Shrub outside for a test.

The stems are rigid enough (thanks to the 22 AWG wire and the clothes hangers) that you can bend them into any arrangement you like. You can also tilt the cells in any direction you wish; toward the sun for example.

As you can see from the final photo below, IT WORKS!!! I'm now able to charge my iPod, iPhone, and other USB powered devices while enjoying the sunshine!

Comments

author
bhvm (author)2017-05-21

What a lovely way to integrate Nature & tech!

author
jwpookie (author)2016-06-08

Ok, it looks too complicated for me. Would you consider selling me one of these? If so, I would look at the specs of my small pump and you could build it for those specs.

author
mikesoniat (author)jwpookie2016-06-08

Hi,

Sure, send me the specs and I'll see if I can come up with something.

Cheers,
Mike

author
jwpookie (author)2016-06-08

Ok, it looks too complicated for me. Would you consider selling me one of these? If so, I would look at the specs of my small pump and you could build it for those specs.

author
jwpookie (author)2016-06-08

Ok, it looks too complicated for me. Would you consider selling me one of these? If so, I would look at the specs of my small pump and you could build it for those specs.

author
jwpookie (author)2016-06-08

I am looking for a way to power a small water pump for a small fountain. Not a fancy large fountain, just one that trickles for the birds. The problem is that all of the times I try to use the small solar panels that come with those other pumps, they must be directly in the sun, I mean if it is off by even the slightest angle they wont work. Do you think this would work for such a thing?

author
MadanN1 (author)2016-03-16

Great idea! What is the rough cost of the materials?

author
DageshF (author)2016-03-15

Solar panels are not ugly.

author
DennisM81 (author)DageshF2016-03-15

Right. We have to stop repeating those negative mantras which people mindlessly parrot when considering going solar. Not all mounting systems are ugly.

author
DennisM81 (author)2016-03-15

How can you tell when your plant is fully charged?

Oh, and solar panels are not ugly when flush mounted on ZEP Solar mounting hardware.

See: http://www.mycarbonfreeenergy.com

author
DageshF (author)2016-03-15

Solar panels are not ugly.

author
lukesjette (author)2016-01-24

I know it's late to comment but this is legit

author
Akin Yildiz (author)2015-10-01

i like putting electronics inside plant pots as well :) good work

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author
pepy (author)Akin Yildiz2016-01-13

What's that? microcontroller?

author
Akin Yildiz (author)pepy2016-01-13

yes, a wifi microcontroller, https://www.instructables.com/id/DIY-Smart-Plant-p...

.

this plant pot can email you when it is thirsty, too cold/hot, not enough light etc. graphs the data online as well.. please check out the rest of the plant doctor instruments; https://www.instructables.com/id/the-Plant-Doctor-...

FZTBL1HIDUFHLNA.jpeg
author
pepy (author)2016-01-13

nice idea....

author
Wilson DanielP (author)2015-07-02

Awesome project!

Can I power a Arduino-like board with this circuit?

author
GanzC (author)2014-08-25

- power supply : should be 5V+ (7805 dropout voltage), so minimum 7.5V

- LED1: wrong polarisation

- R1: it should be calculated using voltage of power supply , so decide what you want to connect (BTW - LED1 it's a waste of energy!)

- 7805 with heatsink? Do You want to boil wather or charge iPhone ? To Low efficiency, use LDO stabilizer or step down dc/dc converter.

author
Bauke (author)GanzC2015-05-28

Hey GanzC,

Thanks for the info! Can you tell me the difference between both?

Thanks!

author
ccandido (author)2015-04-21

Congrats from Brazilian Mirante Lab ... http://mirantelab.wordpress.com

author
aurasolar (author)2015-04-15

This is too beautiful as useful. This solar charger can be used as table decoration. Thanks.

author
LelandG (author)2014-09-08

Would you be able to add a battery, so that it could charge the battery and then plug the device in to charge later when the sun goes down? I'm thinking this would be great for camping, you could put it out next to your tent or whatever and let it charge the battery, then charge your phone later when the sun goes down.

author
mikesoniat (author)LelandG2014-09-09

Yes, that's exactly what I did (and more) in my Solar Shrub II. Check it out

https://www.instructables.com/id/Solar-Shrub-II/

author
ahalya (author)2014-02-13

I need one. How much will it cost if I ask you to make one for me

author
Wolfbane221 (author)2013-12-02

Im trying to make a multiple usb charger station with 5v2a outputs on each one.. is there a circuit I could replicate for each? Power would come from a wall outlet

author
Jobo17 (author)2013-08-15

dude, i looked it up and the circuit alone was over $30

author
mikesoniat (author)Jobo172013-08-15

Well, I had most of the standard components laying around; caps, resistors, diodes, LEDs. Some were certainly purchased in bulk. I just referenced the Radio Shack numbers to specify the right part.

author
geewizard (author)2013-06-22

Great project! I built it according to what you had except i can not get a steady 2V out. When i try to charge a device it charges for a split second then turns off then turns on again and so on. Any suggestions? I tried to add another cap to keep that voltage up but with no success.

author
mikesoniat (author)geewizard2013-06-25

This original version of the Solar Shrub had the limitation that it only charges when in direct sunlight. It's also important that the cells are wired in the correct configuration to give you more than 5 volts. Otherwise, the regulator cannot produce a steady output.

For a more robust design, please take a look at the Solar Shrub II (my second attempt) [https://www.instructables.com/id/Solar-Shrub-II/] it has more power and an internal lithium battery. So it can store a charge and be used with little or no sunlight. Cheers!

author
out-of-the-box (author)2013-05-22

I love this!I have seen a few usb chargers and made a few. I love the personal touches made to this. very unique!

author

Thanks! Have you checked out my latest one? I've improved my original design quite a bit. Here's a link to Solar Shrub II https://www.instructables.com/id/Solar-Shrub-II/

author
BrownDogGadgets (author)2012-07-31

Very nice! Did you ever consider throwing in a super capacitor into the mix in order to store up some charge or smooth out the power flow?

author

Thanks, Joshua! Can you elaborate on that idea? I'm always interested in improving my gadgets.

author

No problem. As solar power is not 100% constant it helps to have some sort of storage in the mix to smooth out the incoming power flow. Or, if for nothing else, a random cloud comes by.

More or less you could add about 6V worth of super capacitor after the 5V regulator (you always want more cap than you'll need). The super caps wouldn't store an insane amount of power, but enough to keep things moving smoothly.

Or add a bunch of AAA rechargeable (5 or 6 of them actually) before the 5V regulator.

Send me a PM. I received a whole bunch of random super caps as samples awhile back and they're just taking up space. I'd be happy to send you a couple for this project.

author
SelkeyMoonbeam (author)2012-07-31

You should enter this in the Hurricane Lasers Contest! https://www.instructables.com/contest/hurricanelasers/

author

Thanks for the heads up Moon Beam!

author
MacOSJoey (author)2012-07-27

Very cool and astethically appealing! One question: Is it waterproof? Could I leave it outside like a regular plant, or will any water fry the circuits?

author
mikesoniat (author)MacOSJoey2012-07-27

Thanks for your comment! I don't think it's weatherproof, but it could be pretty easily. Since the electronics are hidden beneath the CD, I think if you put some silicon sealer around it and in the center, it should be able to withstand a bit of weather.

If you like it, please vote for me in the Green Tech Contest!

author
Dapper Hippo (author)mikesoniat2012-07-28

The spray-on plastic dip you can get at Home Depot could waterproof the components even if water got in the pot.

author
mikesoniat (author)Dapper Hippo2012-07-30

I'll have to give that a look. Thanks!

author
vincent7520 (author)2012-07-29

where do I cast my vote ??

author
mikesoniat (author)vincent75202012-07-29

Hi Vincent, you can vote from the Green Tech Contest "Entries" screen. Here's link: https://www.instructables.com/contest/greentech2012/?show=ENTRIES

Thanks!

author
vincent7520 (author)mikesoniat2012-07-29

Done !…
Glad I did it too : you made my day !…

author
mikesoniat (author)vincent75202012-07-30

Thanks for your vote!

author
ChrysN (author)2012-07-27

Great job, that looks really cool.

author
mikesoniat (author)ChrysN2012-07-27

Thanks! Please vote for me in the Green Tech Contest!

author
ChrysN (author)mikesoniat2012-07-27

Voted!

author
mikesoniat (author)ChrysN2012-07-29

Awesome, Chrys! Thank you!

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