Instructables
Picture of Solar Cockroach 2.0

A while back, I made a little instructable on how to make a simple Solar Cockroach vibrobot out of a 1.5V solar cell and a little vibrating motor. People seemed to enjoy making them and I enjoyed giving them away as odd gifts to my friends instead of buying them real birthday gifts.

All was good in the land... until someone in China decided to stop making the little 1.5V solar cells AND the very efficient little motors which were the backbone of our vibrobot. Sadness fell on many a basement workshop. Little motors all over the world stopped vibrating.

Well, after a bit of searching, replacements were found! A better, and slightly more cockroach sized, solar cell was discovered and tested. A more powerful and flexible motor was bought. Now all of those Solar Cockroach lovers out there can get back to making what they love: lead solder covered children's toys.


In this instructable, I'll be showing you how to put together a Solar Cockroach. As stated above, it's a small vibrobot that uses a solar cell to power a little vibrating motor. It's easy to construct and makes a great gift. How easy is it? I had my neighbor's 13 year old son put one together, and he had never soldered before.

Time: 15-30 minutes
Cost: $5-10
Difficulty: Easy

 
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Step 1: What You Need

Supplies:
1x 2V Solar Cell
1x Vibrating Pager Motor
1X Resistor or diode, or other bits of scrap wire.
2x Big Paper Clip
2x Googly Eyes
Magnet Wire

Tools:
Soldering Iron
Solder
Hot Glue Gun
Wire Cutters
Helping Hand - (Optional, but really... handy)

Where to buy:
You can find these 2V solar cells all over the net. eBay has quite a few people selling them in bulk. You can really use any cell you want, but the big factor is the size. The 2V work well in this case, though a small round cell would be fun to turn into a Solar Ladybug.

You can buy the vibrating motors all over the web. They come in various sizes or shapes. If you have an old cell phone or pager you can steal the vibrating motor out of it. This will save you $2.

I sell completed Cockroaches as well as kits on my website, BrownDogGadgets. I also have a variety of solar cells and vibrating motors if you're in the need.

As I said above, you can easily buy or salvage most of these parts.

*** Update. By request I've put together a non soldering version of this kit. It uses laser cut parts which you paint and pop together. Suitable for younger kids.

Step 2: Solar Cells

Picture of Solar Cells

As I mentioned on the parts list, you can use any sort of solar cell for this project, however, there are some things to keep in mind.

While you can find heaps of different types of solar cells on the internet these days, not every cell is equal.

As we're using little motors, we're going to need a certain amount of power. I've found that most of the little vibrating motors you buy online need at least 1.5V and 30mA to trigger. Now, if we were using batteries, we could just find a battery that has those exact specifications, but as we're using solar we have to go above and beyond. When solar panels are rated, they're given a rating at their max power level which usually means noon on a sunny day. As these conditions don't exist all the time, we have to expect that our solar cell will usually be operating at a lower power level than what it's rated for.

The second thing to keep in mind is the size of the solar cell in relation to your motor. The bigger and heavier the cell the stronger the motor you'll need to get it moving.

The key is to find a solar cell that is both small and has a good kick behind it. Salvaging solar cells from old garden lights has worked for me in the past, though often times they lack the current to get the motor started. The ones I prefer to use are some long and skinny 2V 50mA solar cells. They're cheap and easy to find online from quite a few places.

Step 3: Motors

These little motors can be found everywhere. You've probably got several in your house right now. They're in every cell phone and vibrating game controller, and larger versions can be found inside electric toothbrushes.

As they're common enough, you can salvage them from old cell phones and pagers. The only downside is that they can have a large range of power, and some might not be strong enough to meet your needs.

If you need to buy them, look online. I sell them on my website, and so do such sites like All-Electronics and Electronic Goldmine. They can be found for between $1-2. No matter where you get them, just don't get them at Radio Shack. They're a total rip-off.

In the picture you'll see lots of types of motors. There are countless types, but these are some common ones I've picked up for salvaged.

When buying here is what you must keep in mind:

1) Does it have soldering tabs?

You want a motor with tabs, not wire wires. If you get one with wires you'll have no place to solder to.

2) Does it meet my power needs?

You need one that is rated to work at a very low voltage, 1.5V should be your aim. Most will do this just fine but I've occasionally run into some that need 2.5V or even 3V.

3) Is it strong enough?

You can buy some really small vibrating motors, but they're not going to be strong enough move your roach. Ones that are usually 15mm - 20mm long seem to do the trick.

4) Did I just buy a pancake style vibrating motor?

Goodness I hope not. While they work great for certain things, they don't work well for this project.

5) Did I pay too much?

If you're paying more than $3 for a motor you're paying too much, especially when you figure in that shipping is never free. Just buy one off one of the websites above when you're buying some other hobby items. Find a couple of little projects on instructables and make an order. It saves on shipping.

Step 4: Cut the resistor

Picture of Cut the resistor
solarroachv2-04.jpg

The first step is to cut the resistor. Take some wire cutters and cut the legs off of the resistor.

Go as close to the middle as possible.

Throw away the middle and keep the legs.

Step 5: Bend the legs

Picture of Bend the legs
solarroachv2-07.jpg

I'm using a slightly non-standard motor, one that doesn't have the usual soldering tabs on it. If you've got a motor with usual soldering tabs you can skip this parts.

Because of the type of tabs I have on my motor I need to bend one of my wires. To do this I just take some pliers, grip the very end of one of the resistor legs, and bend at a 90 degree angle.

I only do this on one.

Again, if you've got regular solder tabs you won't need to do this.

Step 6: Solder the motor

The easiest way to solder the motor is to use a "Helping Hand" style holder. You can find these at any electronics store.

Now before you start to solder you must keep in mind that these are small motors and can easily melt if you "over" solder them. You want to put your iron on for a count of three, quickly apply the solder, and pull away. You don't need much solder to make a good connection and I'd hate to see you waste your $2 motor.

First, put the motor into a clip so that the rotating end is inside the clip, and the soldering bits are sticking out.

Second, put the resistor leg in the other clip. Line up the two so they're touching.

Because I'm using a nonstandard motor, my soldering point is the round metal bit on the rear of the motor. This is where I press up my little 90 degree bend bit.

(You can see me soldering a more "standard" motor in my old guide. It's really not complicated.)

Third, line up the solder on one side of the wire next to your solder point.. Then put the soldering iron a little ways up the wire. The heat will flow down and this helps prevent you from overheating and destroying the motor.

The solder should start to flow rather quickly, within a 5 or 6 seconds. If it doesn't, pull away. You want to quickly add solder and get out of there as soon as possible!

Fourth, you'll add the second resistor leg. On a standard vibrating motor you'd just add it to the other little tab, but this is where I like my non-standard motor better. My second tab is the entire outer shell.

So for me I just line up the second wire so it is touching the outer metal shell and then solder the wire on. This allows me more freedom in tight situations.

At this point you should have a motor with two short wires attached to it. Before moving on you should really test out your motor. The most simple way is to just grab a battery and touch the two legs to the ends (a small flat coin battery works best). If the motor starts to vibrate then you're golden, if not then you may have melted you motor. Or you have a bad battery.

Step 7: Solder the solar cell

Now that your motor is all wired up you can solder it to the solar cell.

Just lay the solar cell down and align the wires so that they touch the cell's solder points. It does not matter which wires goes to the positive point and which goes to the negative point.

You'll also want to determine how far you want the motor to stick out of your roach. I like keeping my motor under the solar cell, so they're not sticking out the rear, which means that I don't use the full length of the wire.

Place your soldering iron tip so it is touching both the wire and the solder point, while keeping your solder on the other side. You don't need to go overboard with solder, just bit will do.

Repeat this on the other side.

Once dry, turn your solar cell over just to make sure everything is sticking. If you'd like, you can go outside and test it out. Under bright sun your motor should turn.

Step 8: Cut the paper clips

Picture of Cut the paper clips
solarroachv2-18.jpg
solarroachv2-19.jpg

Using your wire cutters again, cut the large paper clips.

You want to make two sets of even legs.

Just watch out, these things do tend to fly around when you cut them.

Step 9: Glue the legs

Picture of Glue the legs
solarroachv2-21.jpg
solarroachv2-22.jpg

Put your solar panel face down, so the motor is up in the air.

Use your "Helping Hand" again to hold on set of legs.

In one hand grip your hot glue gun, in the other hold the second set of legs.

Now liberally apply hot glue.

Wait for it to melt.

I personally like to have the front legs at an angle so that the back of my roach is higher than the front of my roach. How you do things is up to you.

Step 10: Apply the anntena

Picture of Apply the anntena

Fold your thin magnet wire in half.

Place it in the front middle of your solar cell. It helps to hold onto it.

Apply some hot glue.

Wait for it to dry.

Step 11: Apply eyes

Picture of Apply eyes
solarroachv2-25.jpg

I enjoy giving my roach eyes. It just looks way more cute.

To do this I first apply a little bit of hot glue to the bottom on my solar cell, to the right or left of the antenna.

I then take one eye and smear some glue onto it and move it around to the front.

This way the eye is looking forward yet is really glued to the bottom on the solar cell.

Do this for the second eye as well.

Step 12: Enjoy!

You're done! Now have a roach party!

Take it outside and see it wiggle. Remember you're going to need either some strong sun or a really insanely strong light. When I made the video of a bunch of them on a table it was around 2 on a decently sunny day. When a cloud blocked out the sun they stopped working.

Once you get the hang of it these things are really quick to make. You can probably speed make one in 10-15 minutes. My 13 year old neighbor boy made one in 20 minutes his first time.

I hope this guide and video were helpful. These things are fun to make and are an awesome "first robot" project for kids.

If you'd like a kit or just some random parts you can get them off my website, BrownDogGadgets.com, or off any number of other electrical parts websites. Though keep in mind that 34% of all BrownDogGadgets sales go into doggie treats for one lazy labrador.

*** Update: A non soldering version of the project is now available. It's much better for younger Makers and students.

JAYK01 year ago
You can also get a 1.5v motor from a hex bug
Ploopy1 year ago
Cool
Sorry, bad reading ... Is the resistor really important ? I think you can use a paper clip to make the legs.
Hello, I was wondering what kind of resistor is it ? is it a strong one ? How many ohm ?
I Built it (Battery version) http://wp.me/p15tGa-7d

hey I love the detail and the quality of the pictures of this instructable! Well done and very inspirational. I just made my little version of a vibrating robot here :) I hope you'll enjoy it !

JoshuaZimmerman (author)  cesar harada2 years ago
Cool beans! That looks like insane fun!
So Cute!!!
What's the motor for?
JoshuaZimmerman (author)  papertiger072 years ago
It makes the roach vibrate....
Just so you know roaches have 6 legs, as do all insects. Regardless these are really cute. I want to make one to bug my mom.
hrodriguez72 years ago
not to be mean or anything, but resistors are kinda expensive.
to cut off the wire of the thing just to get the wire is something I woudn't do


I guess it all verries from person to person.
JoshuaZimmerman (author)  hrodriguez72 years ago
They cost 1 cent each when you buy 100 resistors at a time. Buy them off eBay, not Radio Shack.
yeah,(no offense, Radioshack), I relized Radioshack isn't exactly the best place to buy matireal.

I once built a beatlebot and bought stuff at Radioshack and the thing ended up costing $34.00!
JoshuaZimmerman (author)  hrodriguez72 years ago
Exactly. Never buy from Radio shack. Just find a few projects you want to try and go order the parts off an online place. The $5 in shipping is nothing compared the the massive amount of money you'll save from not buying from Radio Shack.

(That being said there are a couple of nice items they make that I do buy from them at a high price, but only because no one else has them.
hrodriguez72 years ago
(you must be going insane now)
how much do "Helping hands" cost?
JoshuaZimmerman (author)  hrodriguez72 years ago
$5-10 most places. Or you could build your own. There are many instructables that show how.
Okay!
Thanks for tolerating my comments
I like this idea for my first bot project. But I can't seem to find the blue-cased motor that you recommend. Are there any others that fill the bill? Or can you tell me how to identify the desired motor if I try to cannibalize a cell phone or such instrument? Thanks.
JoshuaZimmerman (author)  tomgriffin422 years ago
Those blue motors are no longer sold. The ones I use work just fine as well, most any vibrating motors will. I have them on my website.

Just take apart an old (broken) cell phone and you can't miss the motor.
hrodriguez72 years ago
( i hope you're not annoyed with all my comments)
I still dont understand why you can't use the motars that already have wires
JoshuaZimmerman (author)  hrodriguez72 years ago
The wired motors will not work BECAUSE this project needs stiff wires, whereas wired motors have floppy wires. The vibrations would not travel through the floppy wire. You could, however, just use regular solid core wire when soldering.
hrodriguez72 years ago
in the kits that you guys sell, do you pack inthe kinda motars that your using,
or the fancy blue ones.
Any idea if these blinky solar keychains produce enough juice? I see them sold quite cheaply at retail or given out free as promotional logo items. http://www.greenbaba.com/Solar-Gadget/C011-Solar-Key-Chain.html
JoshuaZimmerman (author)  xenobiologista2 years ago
No idea. I'm going to venture to guess no.
First thought: the Orang Asli kids will like this! My friends and I are visiting (every few months or so) some rural indigenous people's communities that aren't connected to the grid. Their school's only power source is solar panels so we have been trying to teach them about solar. This might be a fun toy for a hands-on workshop to show them how electricity works and basic assembly techniques.
Awesome job, Josh!
batonas2 years ago
nice little robot I gues I could build it in 5min but it would be more fun if cockroach would go into dark (like thay usualy do), that would be two morors to photosensors and some forward directing bristle legs, I gues that would be the 3.0 version.
JoshuaZimmerman (author)  batonas2 years ago
Just find a little 1.5V rechargeable battery and wire it in. You can do this, but it does greatly increase the difficulty of the project and takes away from the "newbie" nature of it.
dksergey2 years ago
Robot Lover2 years ago
I like the simplicity of this project! It's so easy that it could be built by a 1st grader while still being a satisfying project for an adult! love it!