Bowlero

To continue my DIY Solar Lantern project, I’ll now talk about the charging module. This is composed of the Nicad battery, Solar Cell, and a diode.

Charging Module

A diode is an electronic component that allows current to flow to one side but not the other way. For solar charging, we would be using a diode to allow current to pass from the solar cell to the battery.

However, during night time when there is no sun, a small current goes from the battery to the solar cell. This is what we would like to prevent and the diode blocks that current.

This is a simple charging circuit but it does not protect the battery from over charging. Maybe in the future, I’ll design something that would automatically switch off the charging process once the battery voltage goes to a pre-determined value. But for now, I’ll just make my DIY solar lantern as simple as possible.

Overcharging is the number 1 cause of battery damage. So for now, I’ll just have to estimate the number of hours I’ll leave my solar lantern under the sun.

The Solar Cell

I’ll be using a mini solar module (solar cell) which has an output voltage of 5v and a current of about 70mA at full sunlight. (This makes about 0.35watts of power).

How long does it take to charge the battery?

This depends on the capacity of the battery. In my case, I have a 280mAh Nicad battery. If my battery is fully depleted, it would take around (280mA/70mA= 4 hours) to fully charge.

Putting it all Together

First is to make a hole at the center of the canister cover. This is where the wire from the solar cell would pass through. I outlined the underside of the solar cell with a double adhesive tape so it will stick well on the cover. This also protects the solar lantern from getting rain so that water won’t go into the center hole where the wire goes. (It is not water proof though so I don’t suggest leaving yours outside if it rains). I might put some silicon someday (the one used in making aquariums) to make it waterproof.

On the underside, I also added a double adhesive tape to close the center hole where the wire passed through. I added some more double adhesive tape and then press down my Nicad battery. I then drilled a hole for the switch.

To be continued….

Technorati Tags: diy, diy solar lantern, solar lantern, solar gadget, solar led lights, solar powered light

One of my project ideas which I have been wanting to do for quite some time now is to make my own solar powered lantern. It basically works something like a solar garden light but it doesn’t automatically turn on when its dark.

Parts list:

• solar cell
• Nicad/Nimh rechargeable battery
• terminal block
• resistor
• diode
• double sided tape
• a switch
• wires
• LEDs
• transparent plastic canister

Tools needed:

• soldering iron
• multi meter (to measure voltage/current)
• wire cutter
• precision screwdriver
• drill
• pliers

Basic Theory of Operation

The solar lantern is composed of 2 main modules. The charging module, and the lighting module. The lighting system would be an LED or a number of LEDs connected to a power source. The charging system would be a way to charge the battery via small solar cell.

Lighting module

This diagram shows how the lighting circuit works. The LED is passed through a resistor to limit the voltage/current that will pass through the LED. It is then connected to the battery.

How to compute for the value of the resistor.

The value of the resistor will depend on what LED you will be using and how much voltage is your power source. A typical LED needs about 15mA of current (0.015A).

In my case, I have a 3.6v Nicad battery, however once fully charged it goes to about 3.9v. Now a typical white LED has a voltage drop of about 3.4v so if I were to compute for the value of the resistor, it would be like this.

3.9v – 3.4v = 0.5v

Using V=IR

R=V/I = 0.5/0.015 = 33 ohms.

Watts = V * I = 0.0075 watts

Find a resistor with the next higher value available in your local electronics store. A 1/4 watt resistor will do.

Series or Parallel LEDs?

In my case, since my battery has only enough voltage for 1 LED, I don’t have a choice but to make a parallel connection. In my research on the internet, most advise not to wire LEDs in parallel. According to some of the articles I read, it is because parallel LEDs causes unstable current distribution. Some LEDs will get more current than it can take. Parallel LEDs can be done only if each LED has is own resistor.
As for now, I don’t have enough resistors so I will kinda violate this for a moment. Worst case is I’ll bust some of the LEDs which would be ok for now since it is not that expensive.

What I’ll be doing is to use 6 LEDs and I would make a parallel connection. Each LED requires about 15mA so the total current needed is 0.015A * 6 so that would be 0.09A or 90mA of current.

Using the V=IR formula again this is the resistor value I need

3.9v-3.4v= 0.5 volts needed to be dropped by the resistor

R=V/I = 0.5v/0.09A = 5.5 or 6 ohms.

Now to give a little allowance, I would use a resistor higher than 6 ohms but lower than the 33 ohms I computed if it were just 1 LED. I happen to have a 27ohm resistor so I’ll use that one.

To be continued…..

diy, solar lantern, diy solar lantern, solar powered lamp, solar flashlight, solar gadget

Technorati Tags: diy, solar lantern, diy solar lantern, solar powered lamp, solar flashlight, solar gadget

Fedora Core 9 Alpha is now available. Note that this isn’t the final FC9 release. This is the Alpha release.

Some of highlights of Fedora 9 Alpha:

• GNOME 2.21 Development Release
• KDE 4.0
• Firefox 3 Beta 2
• Support for resizing ext2, ext3 and NTFS partitions during install
• Support for creating and installing to encrypted filesystems
• PackageKit
• Kernel 2.6.24

And numerous other improvements and enhancements.

The final release is set to happen on April 29, 2008. Should you want more details of the release schedule of FC9, check this out.

The Alpha release is available both through our mirroring system and
via bittorrent.

In Fedoraproject.org here’s the download link:

http://fedoraproject.org/get-prerelease

For direct http access to a local mirror:
http://download.fedoraproject.org/pub/fedora/linux/releases/test/9-Alpha/

For a list of mirrors carrying the content and the various protocols
they support:
http://mirrors.fedoraproject.org/publiclist/Fedora/9-Alpha/

For bittorrent:
http://torrent.fedoraproject.org/

Method 1 (Long Method)

mysqldump -u USER -pPASSWORD DATABASE > filename.sql

copy the file to the new host and restore using

mysql -u USER -pPASSWORD DATABASE < filename.sql

Method 2 (short method)

mysqldump –opt –compress –user=USERHERE –password=PWHERE
–host=SOURCE.HOST.HERE SOURCE_DB_NAME | mysql –user=USERHERE
–password=PWHERE –host=TARGET.HOST.HERE -D TARGET_DB_NAME -C
TARGET_DB_NAME

I was installing ISPConfig to a Fedora Core 7 Installation but when I rebooted, it shows a black screen with a cursor that appears to be “busy”. Logging in remotely via ssh seems to be working but when I check out which process was “hanging” by issuing the “top” command, I see that gdmgreeter seems to be using up a lot of CPU resource. About 70% to 90%.

After searching google for “ISPconfig conflict” “ispconfig gdmgreeter” “ispconfig hang” and similar keywords, the solution I found that worked best was to create/edit the file called “/etc/sysconfig/desktop”

vi /etc/sysconfig/desktop

and add the following two lines to the file /etc/sysconfig/desktop

DESKTOP=”GNOME”
DISPLAYMANAGER=”KDE”
After reboot, everything works properly. I believe this solution also works for Fedora Core 8. Leave a comment if it worked for you.

I just got an email from paypal announcing a new feature which most of us would really be happy about. Now we can withdraw paypal funds directly to your Philippine Bank Account.

Previously, we can only withdraw to a credit/debit card but now, directly to your savings/current account.

There is no fees when withdrawing funds greater than PHP7,000.00 Anything less than that, there’s a PHP50 charge. Not bad if you ask me. PHP50 is still cheaper than remittance fees.

Here’s a rundown of the procedure and here’s a list of the 9digit bank codes you will need when you register.

I was reading about wikia and I found out that they will be having a beta launch on Jan 7. We’ll, it is already January 7 so I tried going to the site to check it out.

The search results seem pretty ok for me so I wondered if search engine spammers were already getting a hold of some pretty valuable keywords like “viagra”.

I then went to http://alpha.search.wikia.com/ and keyed in “viagra” and lo and behold, there was an image at the right side of the screen with a title “People Matching Viagra”. The guy looks very familiar to me and it looks like one of the famous people in the SEO community.

I then moved my mouse over the image and then it says “Matt Cutts”.

Geez! I don’t know if this is some prank or what but I think the search engine war between Google and Wikia has started!!!

I wonder how would Matt Cutts respond to this? Will he put Jimmy Whales photo in google images? (http://images.google.com/images?q=viagra)

Technorati Tags: wikia, viagra, matt cutts, seo, search engine, search engine war, matt, cutts, wikia search

A successful business man was growing old and knew it was time to choose a successor to take over the business.

One man, named Jim, was there that day and he, like the others, received a seed. He went home and excitedly, told his wife the story. She helped him get a pot, soil and he planted the seed. Every day, he would water it and watch to see if it had grown. After about three weeks, some of the other executives began to talk about their seeds and the plants that were beginning to grow.
Jim kept checking his seed, but nothing ever grew.Three weeks, four weeks, five weeks went by, still nothing.By now, others were talking about their plants, but Jim didn’t have a plant and he felt like a failure.

Moral:
If you plant honesty, you will reap trust

So, be careful what you plant now; it will determine what you will reap later.

Are you faced with this message when you use DNSreport from dnsreport.com or dnsstuff.com?

It seems like DNSreport is no longer free. Well, you’re in luck because you are about to see how to make a workaround. With this workaround, you can do multiple dnsreport queries in a day.

Free DNSReport – DNS Report Workaround Procedure for Firefox

1. Click Tools > Options

2. Under the cookies segment, click the Exceptions button

3. Type dnsreport.com and click block.

4. Do another one for dnsstuff.com and click block again

5. click close

6. Click Show CookiesÂ

7. type dnsstuff

8. click remove cookieÂ

9. keep on clicking remove cookie until all dnsstuff.com cookies are deleted.

10. click Close.

11. Enjoy your new found freedom to use dnsreport

I was able to successfully withdraw funds to my HSBC credit card. If you haven’t applied for the Paypal Expanded Use, you can still withdraw but there is a limit to both sending and receiving.
I tried using my HSBC Visa Card and enrolled it for the Paypal Expanded Use last Oct 6. I tried doing a widthrawal from Paypal to Visa just to see if it will work without the Paypal Expanded Use code yet.

The nice thing about using HSBC is you can check for your Paypal expanded use code online via Internet Banking. No need to call some customer service representative who is not yet familiar with Paypal and the Expanded Use Number.

Here’s a screen shot of my account with the paypal transactions.

I tried withdrawing USD50. There was a USD5.00 charge per withdrawal. What was credited to my Visa Card is PHP1,9665.15 only. So the exchange rate used by HSBC was PHP43.69 : USD1.00 Still quite low if you ask me but hey, I got my money from paypal and that’s what matters.

The credit card company will treat this as a payment to your credit card. If you don’t have a balance on your credit card, then you will have an overpayment. If you really wanted to withdraw your money, you need to do a Cash Advance.

Using debit card I think is better since the funds goes to your bank account that is linked to your debit card. No need to do cash advance. Just go to your ATM and withdraw.
Today, I tried keying in my expanded use number and it works fine. At last, I can transfer larger amounts to my local paypal account.