Picture of $3 Emergency Solar Radio

In honor of all my good friends still over in Japan I've decided to create an Instructable for a $3 Emergency Solar Radio. It's a great thing in case of tsunami, nuclear melt down, or zombie invasion. Plus it's really cute when put into an Altoids tin.

My plan is to send this as a (slightly) joke birthday gift to a good friend of mine living in California, who just so happens to be freaking out about possible nuclear clouds. This will also be really nice for her when she starts going camping again this summer.

The design is very simple and only takes about 45 minutes to put together, less if you know what you're doing.

If you'd rather not make one yourself, I'll probably be throwing up a couple completed ones as well as most of the parts over at my website BrownDogGadgets.com.

Step 1: What you need

Picture of What you need

I bought all the supplies I needed from my local $1 Store. (If in Japan, a 100 Yen store.)

To buy:
1x FM Radio
2x Solar Garden Light
1x Diode ($1 for 100 of them online, or take one out of any random junk pile)

If your local $1 Store isn't as cool as mine, you can probably find these things locally, online (like at my website BrownDogGadgets.com), or from a trash bin.

Soldering Iron
Wire Strippers

Altoids Tin
Hot Glue
Mini Speakers ($1 Store, or take apart old headphones)

Support Me By Buying Some Parts...

If you can't find solar cells or cheap AAA batteries, I have quite a few on my website BrownDogGadgets.com. The same solar cells I use to make my Solar Cockroach would work great for this project. You could also slap on a bigger, more powerful cell onto the outside of the tin like these nice 4.5 volt cells.

I also some AAA battery holders and very cheap AAA batteries for sale that have a much higher capacity than the ones you'd find in your average solar light.

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Femetheus15 days ago

I used the same radio, but the wires connecting to the battery came off the plastic case as I was removing the housing, and now I can't get them back on. How are these little wires affixed originally when the radio comes from the store, with glue? Or am I just better off buying another little radio to start again?

T0BY2 months ago

This is a beautifully elegant little radio. You have done very well to make it for so little money, I am very impressed!

Colaris2 months ago

If it's powered by the Sun do you need the batteries?

GrantK43 months ago

Where did you get that one type of radio? I looked everywhere, and the only place I found it was Alibaba, but it was only in 5000 piece bulk package. I am in North Carolina, if there are any specific stores that have it here.

MatamoriJon4 months ago

Hey nice instructable, i have a few questions though.

First, can i use a solar cell from a calculator?

Second, does it have to be a specific diode?

Third, can i use normal batteries instead of those used for solar cells?

Fourth, whats the diode for?

JoshuaZimmerman (author)  MatamoriJon3 months ago

1) No, not strong enough by a mile.

2) 1N914 is the standard and super common one to use.

3) No, you need rechargeables so they can recharge. Regular batteries will... possibly leak or explode.

I could (almost) make one of these following these instructions. I even have everything I need already. I was going to say except for the diode, but odds are there are some floating around here somewhere...

Just one question: Why do you have to throw the solar cell away if you break off the solder point? Can't you just re-solder it? I know this was already asked, but I don't see an answer, and I was wondering the same thing.

JoshuaZimmerman (author)  ThisIsMyNameOK6 months ago

With these type of cells if you break off the solder point, then there is no way to make a connection. If you use better solar cells you'll have an easier time. I was just using super cheap recycled $1 Store solar cells. Spending $5 on a better solar cell will make life a lot better.

Ah... I see. Thank you for your reply. I know nothing about these kinds of things and it just seemed like it was wasteful to throw it away.

klmyles6 months ago

Would a Digitally Tuned radio work??

(see this one I found - http://www.dollargeneral.com/product/index.jsp?pro...

JoshuaZimmerman (author)  klmyles6 months ago


christina.liittle made it!8 months ago



Super well done!

Skeleton key97 made it!1 year ago

i made it!!!!!! hahaa. its easy enough

JoshuaZimmerman (author)  Skeleton key976 months ago


wazy8011 year ago
why do you have to drill on step 7?????

To make a hole for an earphone jack

Oh,my radio is the same as yours.

Just FYI, the reason that this works and receives a signal through the Altoids tin is because the headphones are the antenna. If you use speakers, you might need a separate FM antenna. Hope this helps.

kfrancis911 year ago

If you break off the solder point from the solar cell, couldn't you just solder it back on?

josuchav1 year ago

you misspelt goggles

ajensen271 year ago
found 2 separate lights around the house. one has a 2/3 aa battery and its panel puts out 1.2v and the other has a AA battery and its panel puts out .95-.97 volts sitting under 40w bulb(it was night out). which panel do i use and how many. also do i need the diode?
Kirbsome!4 years ago
Quick tip:
When buying solar powered lights for this, look for blue solar panels.
They are usually higher quality than the dark brown ones.
thanks good to know
JoshuaZimmerman (author)  Kirbsome!4 years ago
Very true. Those CIS are dark brown and very high quality...
This has got to be one of the single most coolest things on instructables!
wazy8011 year ago
what kind of tap do I use o step 8???
Nhoj162 years ago
I just began making this when I realized I'm out of diodes. Will it still function without one?
Nhoj162 years ago
Cool project! I think I have all that I need to make this laying around so I'll definitely do it.
Jacky P2 years ago
What diode do I use?
i suggest a schematic diagram for the project. please to make things simple
Whatat does the diode do in the circuit? Just curious
Orkekum2 years ago
awesome idea and well written, i can buy cheap radio with a scan button and a return one
JoshuaZimmerman (author) 4 years ago
Just because I'm a teacher doesn't mean that I'm not human.

With feelings to be hurt...

teachers are awesome c:
deanes2 years ago
Altoid tins are neat, but maybe an easier more practical project would be to just add the charging panels directly to the radio case? Or, maybe the panels glued to a plastic pocket-shaped sheet and connected by a sturdy wire to the radio battery compartment. Then you would have a solar charging case for the radio.
JoshuaZimmerman (author)  deanes2 years ago
Probably, but this is rather bare bones. Plus cute. You gotta factor in the cute aspect.
DAND4 years ago
What type of diode did you use?
static DAND2 years ago
 The current carrying capability, the voltage rating and the voltage drop across the diode are considerations. Too much current can harm the diode, too much over voltage drop, the batteries may not fully charge. Nominal figures; for the silicon diode used here is .7 V, for the Schottky diode it's .2 V. In most solar application the Schottky is preferred, but one can't walk into radio shack and buy one. In low powered projects like this, it's easier to add an extra salvage solar cell, and used the more readily available silicone diode. No precision is required on the voltage rating here as long as it's higher than the battery voltage, the voltage rating is important if the diode will see a reverse bias as part as normal desired operation.
JoshuaZimmerman (author)  DAND4 years ago
1N914. Very common. You can find them everywhere.
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