Science Fair Experiment

meowmixcat15 · Post by **meowmixcat15** » Sun Jan 09, 2005 4:46 pm

I need to know how to build a solar-powered computer using an old laptop that still works. Please help!

meowmixcat15 · Post by **meowmixcat15** » Sun Jan 09, 2005 4:51 pm

Please Help me! I need to Know how to do this thing! Im Desperate!

meowmixcat15 · Post by **meowmixcat15** » Sun Jan 09, 2005 5:33 pm

Im not that desperate, but my project is do Thursday and I can't get the computer to work! I need to know if I should keep the computer and say it didnt work in my results or eliminate it and just use my solar-powered oven (I built both!). Please help me if you can! Thanx!

davidmoilanen · Post by **davidmoilanen** » Mon Jan 10, 2005 9:44 am

If you've already built a solar powered oven, it shouldn't be too difficult to hook your solar cell up to the computer. I assume that you have a solar cell that's powering your oven. As far as I know, laptops usually run on DC power which is the same power that a battery or a solar cell puts out. That's why when you hook your laptop up to a regular power outlet, the power cord has that strange box thing in the middle of it. That's the inverter which converts AC power to DC power. So the idea is that somehow you need to connect your solar cell to the power input of your computer. Like a battery, your solar cell should have a + terminal and a - terminal. The power input for your computer also has part of it which should be connected to the + wire and part of it which should be connected to the - wire. I'm not sure which part is which but if you can get access to a voltmeter you can probably figure it out. Often the middle part is the + part and the outside is the - part. Once you figure out which is which you should be able to hook up your wires from the solar cell to each part of the power input. Hopefully your solar cell can produce enough current to power the computer. If it doesn't produce enough current you may not be able to power the computer.

Hope that helps

meowmixcat15 · Post by **meowmixcat15** » Mon Jan 10, 2005 1:34 pm

I dont think I have a solar cell. How do u tell if u have one or not? [/size]

htb · Post by **htb** » Mon Jan 10, 2005 11:57 pm

meowmixcat15 wrote:I dont think I have a solar cell. How do u tell if u have one or not? [/size]

first off- you really can't expect a detailed reply in less than 60 minutes since most of us are professionals or students and are quite busy: you had 3 posts begging for help in less than this time period. Furthermore, I'd suggest that you not wait until the last minute since you'll need a good understanding of the components required for a solar powered device. You're not likely to get much sympathy if you ask for someone to do all of your research for you, rather than doing it yourself.

A solar cell is a device that converts light energy into electric current- you've probably seen them on solar calculators or as the black panels that look like "wings" on satellites. Here are some places to learn about solar cells- I did a google search for these and it's really easy to find more information if you need it. Let us know if you need additional help:

http://www.howstuffworks.com/solar-cell.htm (this was the first hit on a google search for "solar cell", and a good starting point)
http://www.nrel.gov/clean_energy/photovoltaic.html
http://www.solarcellsales.com/

htb

shijun · Post by **shijun** » Tue Jan 11, 2005 12:09 pm

Hi Meowmixcat15,

I just would like to give you a couple of pointers about making posts in the Ask an Expert Forum:

1) Please do some research on your own and give your question an initial try. Start with a simple internet search using one of the search engines e.g. Google.

2) Please describe clearly what you are doing and what you have found so far. It's MUCH easier for one of our volunteer scientists to help you if he/she has something concrete to work with and a sign that you have given a good shot at attempting to find the answer.

3) Do not wait until the last minute so you sound so desperate. Like htb said, it's hard for someone to help you if it's obvious that you have been procrastinating or are just lazy. Our volunteers are humans too (not machines who crunch out answers), and please work with them like how you work with a personal tutor. Give a good effort, ask questions, and keep trying! Believe me, you'll go much farther...

4) Instead of dashing off short posts with questions one after another, please give some thought first to what you are writing and present your questions and ideas clearly and concisely (just like how you write for a school assignment). This message board is not IM, and again, it's just so much easier (and more considerate on your part) on our Experts when they don't have to keep on replying to a continuous stream of questions that show little thought.

5) Finally, please keep in mind that the easier you make it for our Experts to help you, the more you'll be helped! Just put yourself in their shoes and you'll see what I am talking about.

Good Luck!

Shijun

meowmixcat15 · Post by **meowmixcat15** » Tue Jan 11, 2005 8:17 pm

shijun wrote: 1) Please do some research on your own and give your question an initial try. Start with a simple internet search using one of the search engines e.g. Google.

3) Do not wait until the last minute so you sound so desperate. Like htb said, it's hard for someone to help you if it's obvious that you have been procrastinating or are just lazy. Our volunteers are humans too (not machines who crunch out answers), and please work with them like how you work with a personal tutor. Give a good effort, ask questions, and keep trying! Believe me, you'll go much farther...

I did do research but it didn't say that I needed a solar cell and I didn't know what a solar cell was when my first reply came back and said that I needed a solar cell. Thank you all who replied and helped me out. You are right. I shouldn't have waited till the last minute for my project, but I did work on it a lot and did not procrasinate for the most part. Thank you all again and I hope my questions and replies I've got have helped others.

meowmixcat15 · Post by **meowmixcat15** » Wed Jan 12, 2005 6:55 am

I have built my solar powered computer correctly and I have attached the solar panel, but it still doesn't work! I don't know what went wrong! I followed all directions and double-checked everything and it still didn't work! What could go wrong in building a solar powered computer?

hzatz · Post by **hzatz** » Wed Jan 12, 2005 12:49 pm

Assuming that you've attached the solar cell correctly (+ to +, - to -), there are several details to watch out for:

Does the voltage output of the solar cell match the voltage required by the computer? The solar cell would probably need to generate 90-150% of the voltage that the computer was expecting.

Does the solar cell generate enough current to charge or run the computer? Solar cells generally don't generate a lot of current, unless they're rather large and expensive. That's why they aren't used more commonly for this sort of thing.

Is the solar cell receiving enough light to generate the voltage and current mentioned above?

The computer's charger should specify how many volts it needs. You can use a voltmeter to find out what the solar cell is generating.

meowmixcat15 · Post by **meowmixcat15** » Thu Jan 13, 2005 10:01 am

I don't know if my computer has a solar cell or not. How would you be able to get one? What store could you find it at Thanx! meowmixcat15

davidkallman2 · Post by **davidkallman2** » Thu Jan 13, 2005 7:17 pm

Hi meowmixcat15,

You can usually spot a built-in solar cell/battery as a small gray panel on top of the powered device. If the device does not have a built-in battery, you'll have to use an add-on battery. A general electronics store, such as, Radio Shack, should have add-on solar cell/batteries. If they do, though, I don't know if they will provide enough power for the application you have in mind.

In that case, a specialiality retailer may be required. I don't know how to help here. Anyone else have any suggestions? [I'm trying to help out here (since no one was responding), based on things I've heard; this is beyond my normal area of expertise, so please use with caution.][/u][/i]

EDS · Post by **EDS** » Thu Jan 13, 2005 11:15 pm

Hi Meowmix,

I'm afraid I don't understand quite what you're doing. In one post you say that you've attached a solar panel to the computer, but later you say you aren't sure if you have a solar panel. You'll probably have to go into more detail about what equipment you have and what you've done with it before you can get a response detailed enough to be helpful.

I can say that for most ordinary computers, trying to power one with a solar cell is going to be hard to do. You'll probably need a large, expensive solar panel, something that's a couple of square feet in area and costs a few hundred dollars if you buy it new. (You might be able to find a deal at a used electronics store, a ham radio swap meet, or online. I can offer some suggestions if you want.) An ordinary laptop computer requires many tens of watts to run. A small solar panel like you can buy at radio shack for a few dollars will probably only put out a fraction of a watt.

An alternative may be to use a small solar cell to charge a battery. By charging a battery for days and then using it for a few minutes, you could run a computer using a smaller and much cheaper solar panel. But you'll still need a big battery and some electronic components.

Putting that kind of thing together will take considerable engineering skill and a fair bit of money. (I'd guess a minimum of something like 40 bucks if you buy cheapest possible parts, already own the required tools, and build everything yourself, much more if you need to buy tools or a pre-assembled battery charger.)

Unless you have a well stocked tool cabinet and some previous experience with electronics, this is a going to be a very big and expensive project and may take months to complete.

Some alternatives might be powering a much smaller device with a solar panel. Battery powered clocks, calculators, and things like that would be a lot easier.

meowmixcat15 · Post by **meowmixcat15** » Sat Jan 15, 2005 9:15 pm

Hey everyone! Thank you so much for all your help! Unforunately, I couldn't find a solar cell battery, but I did finish my project. Even though the computer didn't work, which was a bummer, I still did a good job. I will post my grade as soon as I get it and tell you everything that I did as soon as possible. Also, if anyone wants my help or needs advice just post your topic under Physical Science and Math and put your topic as "meowmixcat15 question." Thank you everyone who helped me and I hope I can help others also!

Meowmixcat15

meowmixcat15 · Post by **meowmixcat15** » Mon Jan 31, 2005 3:06 pm

I would like to let everyone know i got a B!

I know i can do better

but what are you going to do, right? Thanks again for all the help! I really appreciate it!