Introduction: Mr. Buzz, the USB Solar Charger in a Cup

Picture of Mr. Buzz, the USB Solar Charger in a Cup
Mr. Buzz is a solar powered USB charger in a cup! The lightweight and flexible PowerFilm solar panel charges up the 2400mA battery pack so you can recharge your USB device even without the sun.

What's so cool about Mr. Buzz?
  • Uses flexible solar panels that are extremely light, unbreakable and can be mounted on nearly anything.
  • Rechargeable batteries in the cup let you charge / power your device even if the sun isn't out.
  • Total power storage of around 2,500 mA, more than enough for a full iPhone recharge, or multiple recharges for smaller devices, like a shuffle. 
  • Has a USB 'Type A' jack, the same jack that's on your computer, so you can connect to any USB device.
Mr. Buzz is available as a kit from Gadget Gangster.

Step 1: FAQ

Picture of FAQ

What is Mr. Buzz?
Mr. Buzz is a solar powered USB charger. A flexible solar panel (PowerFilm) is used to charge Nimh batteries, so Mr. Buzz can charge up your USB device even if there isn't any sun.

What can I charge with it?
Mr. Buzz uses a 'Type A' USB Jack, the same style USB jack that's on your computer, so it will physically connect to nearly any USB device. That said, some devices don't like being charged by a battery pack or solar panel.

Usually, if you plug your device into your computer and it needs to install software before it begins charging, it will not work. Here's what I've tested:

Apple iPod: Mini, Nano, Shuffle 1G/2G, Classic, Touch, iPhone
Creative Zen Micro
Nintendo DS (with an adapter cable)
Microsoft Zune
ATT Fuze, aka Touch Pro
Motorola S9-HD
PS3 Bluetooth Headset (in holder)
Verizon PPC 6700 (HTC Apache)
Creative Vado
Creative Zen Stone

So far, any device that doesn't work with my usb wall charger will also not work with Mr. Buzz.  I've tried;
PS3 Wireless Controller
Xbox 360 Wireless Controller

How long to does it take to recharge?
It should take the same amount of time as if it were plugged into a wall charger or any other device. To charge my phone from dead to 75% takes 90 minutes (same as a wall charger).

How much juice does it have?
Total power storage is about 2,500 milliamps. This is enough to charge my phone (which has a 1,300 mA battery) about 2 full times. An iPhone's battery is 1,200 mA, so you should about 2 charges, too. Smaller devices (like a shuffle) will recharge many, many times.

What batteries should I use?
You should only use rechargeable AA batteries (Nickel-Metal Hydride).  With 4 batteries, Mr. Buzz provides 4.8v-5.2v.

Do I have to use batteries?
Yes - the solar panel slowly trickle-charges your batteries, and they aren't large enough to directly power your USB device.

Mr. Buzz was designed by James Long at Lil' Brother SMT Assembly.  A kit or bare PCB are available at Gadget Gangster.

Step 2: Preparation: Tools

This is a great project to learn how to solder. It only takes about 15 minutes to put together, too. There are a ton of great instructables on how to solder (one here).

You'll need a few tools to assemble the project;

1 - Soldering Iron and solder. Leaded solder is easier to work with, and a 15-40 watt iron is just fine. A conical or chisel tip works well.

2 - Dikes. Diagonal cutters are used to trim the excess leads from components after soldering them down. 

3 - Batteries. Mr. Buzz needs 4xAA rechargeable NiMh batteries.

Step 3: Preparation: Parts List

Picture of Preparation: Parts List

Here are the parts you'll need to put Mr. Buzz together. If you've ordered the kit from Gadget Gangster, double check to make sure your kit has all the parts listed. If there's anything missing, just email us at;

Eagle 4xAA Battery Box
Mouser Part #
Qty: 1

Mr. Buzz Circuit Board
Source: Gadget Gangster

.1uF Ceramic Capacitor
Qty: 2

100k ohm 1/4W Resistor (Brown - Black - Yellow)
Qty: 2

USB Type A Jack
Mouser Part#
Qty: 1

About 1 Foot of Hookup Wire

3V PowerFilm Solar Panels
Source: PowerFilm
Qty: 2

Not included in the kit are 4xAA rechargeable batteries, which you'll need to provide. 

Step 4: Make It: Step I

Picture of Make It: Step I

Ready to begin? Building Mr. Buzz is easy. Let's start with the resistors.

Take the 2 resistors (100k ohm, marked Brown - Black - Yellow), bend the leads at a 90 degree angle and insert them into R1 and R2.

Flip over the pcb, solder down the parts and trim off the excess leads.

Step 5: Make It: Step II

Picture of Make It: Step II

Take the two Ceramic capacitors and insert them into C1 and C2. These caps aren't polarized, so it doesn't matter which direction they go in the pcb.

Flip over the board, solder them down and trim off the excess leads. Save one of the excess leads for the next step.

Step 6: Make It: Step III

Picture of Make It: Step III

With the bit of excess lead you saved from the last step, you're going to bridge a connection on the board.

Bend the wire in a 'U' shape, and insert one end in the hole marked 'NoREG', the other end goes in the middle hole.

Why is this jumper here? If you want to use Mr. Buzz with a bigger solar panel or another power source, you can do so with this circuit board! You just jump the middle hole to 'Reg' and jump the two holes in the 'REG Enable' box. You would then add a voltage regulator at U1.

You'll want to use a 5V regulator.  NOTE: The pinouts for the regulator aren't compatible with the 78xx regulators, you'll want to use something like this, instead.

Step 7: Make It: Step IV

Picture of Make It: Step IV

We're almost done with the board - we just need to add the USB jack. Take a look at the photo. Drop the USB jack in the board, flip it over and solder it down.

Step 8: Make It: Step V

Picture of Make It: Step V

Add the battery box as indicated in the photo. The red wire goes in the hole marked '+' and the black wire goes in the hole marked '-'.

Step 9: Make It: Step VI

Picture of Make It: Step VI

Now, let's work on the panel.

First: Set the 2 panels on the table, exactly as shown. Note that each panel is polarized, the pattern on the panel (the repeating 'T' pattern) shows you the correct polarity.

Take a bit of hookup wire (or some of the extra leads you've trimmed off) and set it on the panels, as shown on the photo. This wire is going to be used to connect the panels in series.

With your soldering iron in one hand and some solder in the other, solder the extra wire straight to the copper 'braid' on the panel. There's a very thin film over the copper braid - don't worry about it, your solder will melt right through it and adhere to the copper braid. Once you've got it affixed to the first panel, connect the other end to the other panel, as shown in the photo.

Take the remaining hookup wire and cut it in half (2x 6 inch lengths). You'll use this wire to connect the panel to the Mr. Buzz circuit board.

Step 10: Make It: Step VII

Picture of Make It: Step VII

Finally, connect the panel to the circuit board. Note on the photo how the panel connects.

That's it - You're all done!

Usage and Mounting
I suggest you join the 2 panels with a bit of scotch tape - it will make them more rigid. To mount it, you can tape it directly to a surface, use double-stick tape, or just let it hang freely. PowerFilm is very durable and flexible - I wouldn't fold it or crush it, but it will curve around a soda can, coffee cup, or on a backpack.

To use Mr. Buzz, just add your rechargeable batteries and flip the 'on' switch on the battery back and plug your device in. Charging should start immediately. Also, if you're not charging Mr. Buzz's batteries or charging your USB device, you should flip the battery switch to 'off'. If you don't, the batteries will slowly lose their charge.

Step 11: Downloads

I hope you enjoy Mr. Buzz! Let me know what you think by commenting on this instructable or sending me an email at

There's no software for Mr. Buzz, but here's a simplified schematic:
Diptrace format - jpg

And here's the board layout
Diptrace format - jpg

Buy the kit or Circuit Board from Gadget Gangster


awaite76 (author)2017-02-26

I realize that this project is a bit dated, but I was wondering if anyone happens to have the original schematic for the Mr. Buz circuit board? It seems that the original site / link do not work.


JeenJogi (author)2012-05-16

Commercial Solar Panels are Expensive!
Fact: It will take you more than 10 years to pay back
Solution: Using Surplus Solar Cells You can get pay back in 1-2 years
There is an Engineer from Chicago his name is John Sommer
He explain it All in his diy solar panels Blog Search for him using Google
Type "top diy solar panels" Open the first Result.
Note: Ignore the adds at the top.

susie (author)2009-12-10

This gives me cognitive dissonance. Seems like it should be something you can heat your coffee with...I don't totally get why you'd want a charger in a cup vs. it being packaged some other way. Am I missing something??

Putting it in your car cup holder wouldn't charge that's not a reason for it to be in a cup.

Off the top of my head a solar charger that can screw onto a Gorilla tripod that I could clamp onto a roof rack while driving, clamp on a table near the window etc. would be something I might use.

tn. (author)susie2011-06-21

strange - when i read "charger in a coffee cup" i thought "wow - that'd be great at the office or on the go". i totally didn't get "gee - that's a lame idea", so thank you for that.

that being said, the whole point of this website is imagination - if you don't like the coffee cup, put it in an altoids tin or heck, an empty pasta box if you want.

Gadget Gangster (author)susie2009-12-10

Ha!  It will NOT warm your coffee. 

I put it in a cup because it was the first thing I thought of , but I use it on a window sill (and it works fine there).

But you can mount it on just about anything - a hat, directly on a window, or not even mount it at all - up to you.

monte the magnificent (author)2010-10-21

Quick Question: On the Gadget Gangster page it says the resistors have a 1/2 W limit but in this instructable it is listed at 1/4 W. Does it matter which one uses to build the charger? Thanks and great instructable.

No, it doesn't matter. 1/4W (or smaller) is just fine.

Jr Hacking kid (author)2009-12-09

What if i want to use a bigger solar panel what voltage is needed to charge this upp and dose the kit come with everythin except the battery?

Yes - Kit comes with everything but the batteries.

If you use a larger panel and it's also 6V, you'll be fine.  If you want to use a higher voltage panel, you'll need to add a regulator.  

There's a space for it on the board, but the regulator isn't part of the kit.  You can use this one.

The voltage regulator , You Have on your site Is this the one?

Yep - same one.

ohk XD

Yea i left this project for a while until i found it sitting on the side

Well its the summer time to finish my solar bag build

oh ohk thank you that helped me out so where i put the jumper i place the regulator in there right?

xiaoyang88 (author)2010-02-26

 Hello nmcclana! I have been looking for the recommended LDO regulator, but there is no online retailer based in the UK. Mouser currently has the recommended regulator on back order. Could you please help me find another regulator? I have bought a MPT6-150 to replace the original panels. Also, if I want to put in a diode, where should I put it? Thank you for you help.

snotty (author)2009-12-11

All this project really needs is a diode to keep the batteries from draining through the panel when it's dark.

Of course this would drop the voltage a bit so we'd need a slightly higher voltage panel. Maybe a 6 volt panel like the Powerfilm MPT6-75 would work.

Who can recommend a panel and diode to perfect this elegant charger?

Jr Hacking kid (author)snotty2010-01-12

hmm i placed a 1n4007 dioed

 Hello Jr Hacking kid, I want to place a diode to prevent the batteries from draining  as well. Can you tell me where i should place the diode on this circuit board? Thank you!!

Jr Hacking kid (author)2010-02-07

its been a month since i have this kit! And it works great but since my wires keep on breaking im going to upgrade it so right now it is not working and being upgraded ill be bck with more pics bye

Jr Hacking kid (author)2010-01-12

I got my Kit as a gift from My cousin My Kit was #238 And Here is some pics of my finished kit Ill up greade it some time soon To a 6v 200mAh solar cell and placed in my bag but i just placed it in a cup becuze why not follow the orginal first then make it unquic So here you go!!!

Jr Hacking kid (author)2010-01-06
hmm you should sell that
lDO RegulatorPower5V800mA 
part in the store product page too
XDleader555 (author)2009-12-25

The solar cells are not working... I can charge using the batteries though. Nice ible

The solar panels won't charge anything by themselves (they only produce 50mAH @ 6V).  But they'll trickle charge your battery, so your battery can do the charging. 

but there is no voltage when i put the solar film in the light and test it with a volt meter. I soldered the wires to it, what am i doing wrong?

Gadget Gangster (author)2009-12-27

I've updated the 'ible to reflect also using a regulator (this step, in particular).  I recommend using the MPT6-150, you can run them in parallel to get more mah, too - the regulator I recommend is more than enough - about 800mA. 

Ohh Yea i am sorry for deliting it idid it by accdent  cliked on it and didnt read it lol

But for thos who are wondering Wtf we are talking about  READ BELOW!

i think im going to get either two of these and solder them parallel so i get 200mah
POWERFILM,MPT6-150 rating at 6v and 100mah each

POWERFILM,P7.2-75 rating att 7.2v and 100mah

what do you think is better?

Ohk Thank you verry much! XD

Ill be ording this some time soon!

Jr Hacking kid (author)2009-12-26

What size starbucks cup did you put it in?

Venti?  The smallest one.  It would work in a bigger cup, of course. 

snotty (author)2009-12-11

Nice simple project!

What are the capacitors for?
What do they do?

Jayefuu (author)2009-12-08

Ummm... In step 1 your talk about how much "juice" it has. You use milliamps to quantify the amount of charge it can store. Amps are a unit of current, do you mean ampere-hours? mAh?

PKM (author)Jayefuu2009-12-08

Further to what Jayefuu said:

Milliamps are not a measure of energy, they are a measure of current.
Neither are milliamp-hours a measure of energy, unless multiplied by a voltage.  I don't know if that's the ~6V AA pack or the 5V USB output. 
You also can't compare milliamp-hours between different batteries with different voltages.  Your iPod battery is a lithium at 3.7V, for which 1200mAh is less energy than 1200mAh in your 4 AAs.
(Technically "power storage" is wrong as well, you store energy, but in this case it's obvious what you mean)

Please don't think I'm just criticising out of pedantry- it's because what you have written is incorrect and very ambiguous.  If it was just given out of interest it wouldn't be so bad but it's actually important for what you are building.  It's like giving dimensions for how to build something in feet instead of square feet- I could assume you mean square feet, but that isn't what you said and I might be wrong.

On top of this, I have seen people do completely the wrong calculation for LED resistors or battery capacities by using the wrong quantities, and coincidentally not blow anything up because they were in the right area.  I'd hate to wreck an iPod by trying to charge it with 1300 mA :)

CameronSS (author)PKM2009-12-11

I don't know if that's the ~6V AA pack or the 5V USB output.

It's pretty close to a 5V AA pack, actually. These are NiMH batteries, not alkalines, so they're rated for 1.2V, not 1.5V. 4*1.2=4.8V, and slightly more when fully charged. It still needs clarification, but the total energy storage won't change a whole lot.

Gadget Gangster (author)PKM2009-12-08

You are correct, it is mA/h, and it's not meaningful unless the output voltage is also provided.  I do provide the output voltage in step 1 (the faq), it's 4.8v-5.2v.  In the intro, I was just trying to summarize. I was thinking most people would figure that a USB charger would provide USB-level voltage, but I specified it, just in case.  An iPod's internal battery is 3.7v, but the internal circuitry chargers it from the usb +5v.         

MePerson (author)2009-12-10

 Now all you have to do is combine this and the Roof Coffee Cup

HEY YOU (author)2009-12-10

Nice Instructable!!

I thought it was a solar powered coffee cup


grandtippler (author)2009-12-08

 Great idea, I need one of these.

lemonie (author)2009-12-08

Wouldn't the angle be better with the cup stood upside-down?


Gadget Gangster (author)lemonie2009-12-08

I actually tested several different mounting types (Mounting on a cup is only one idea). 

I didn't notice a significant performance difference when the cup was flipped upside down, and I like how the USB cable comes out of the cup spout.  It probably depends on the sun's position, ambient light, etc. 

But it can be mounted to nearly anything, I tested a hat brim, backpack and a laptop bag. 

lemonie (author)Gadget Gangster2009-12-08

Hat-brim? Now that's a good idea - mount a cooling-fan - summer-wear!


dxmonger (author)2009-12-08

The solar panels in this DIY are available through PowerFilm at:

Or on the PowerFilm Solar store at Amazon.

They have many other types of flexible solar modules.

Gadget Gangster (author)dxmonger2009-12-08

Yeah, I included that link in the parts list.  They have a variety of different sizes and voltages.  For Mr Buzz, I used 2 of the small 3v panels to keep the cost of the kit down and to make it easier to mount on more stuff. 

Rigid panels have a higher conversion efficiency, but I didn't want to use something that might break.  The PowerFilm is very durable - it has a similar consistency / feel of an old overhead projector transparency film. 

Doctor What (author)2009-12-08

I like the idea.

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