DIY iPhone Charger

Finally, after a few weeks of waiting, I’ve managed to proof that my iPhone charger concept works! Special thanks to Jia Ying who helped me buy components from Pudu. Here’s how to build your own iPhone charger:



All you need are the 4 resistors stated above. I have modified some values of the resistors because of some miscalculation. Connect them as shown and provide the circuit with a regulated 5v supply. Get a female USB plug and connect it as shown to the circuit. Make sure the positive and negative terminals are connected correctly. The D+ and D- pins have low currents so connecting them wrongly may not blow up your iPhone.

Once you are done, triple-check your circuit. Use a voltmeter to make sure everything is correct. Then plug in your iPhone and you should be greeted with the charging chime, indicating that your iPhone is now charging properly.

Practical application: In-car iPhone charger.

A normal cheap car USB charger.

I have tons of USB car chargers lying around because it seems like every device that I buy comes with one free. These chargers are very simple in construction. They take in 12V and they output a regulated 5V to the USB ports. These cheap chargers will not work with the iPhone because the D+ and D- pins are not connected. I can remember at least one incident when I need to charge my iPhone but couldn’t because I didn’t have the proper car charger.

This charger is a bit special because it uses switching (pulse width modulation) to get 5V from 12V.

So with the circuit diagram above, I constructed the voltage divider circuit and put it into the charger. It’s wrapped in tape to prevent it from shorting.

It works!

Now I can charge my iPhone when I’m traveling long distances.

Other practical applications: External battery.

Get a high capacity battery (8.4v @ 3000mah for example) and use a 7805 to regulate it to 5v. Then feed it to the circuit above and you’ll be able to charge your iPhone when you’re not in a car or near a wall socket. If you use 6 AA batteries (9v), you can charge your iPhone anyplace where you can find batteries. That’s almost anywhere in the world! The days of running out of juice is over!

Disclaimer: I will not be responsible if you destroy you iPhone with the information posted here. I have tested the circuit and it works perfectly with my iPhone. If you plan to build this circuit, please triple-check everything before plugging your iPhone in. Happy charging!

Update: DIY iPhone 3G charger. Also explained: why the iPhone charges when reference voltages are applied. Continue reading

World's First Self-Replicating 3D Printer

If the title doesn’t send a shiver down your spine, you should watch the Matrix Trilogy again and maybe Virus, which is a very old movie about an outer space virus taking over an advanced research lab and building robots using other robots. The future belongs to the machines. It takes a human 9 months to reproduce one, or maybe two or three (in the case of twins and triplets). They didn’t mention, but I think it will take the 3D printer less than 10 days to replicate itself. Once there are 2, they will be able to make another 2 simultaneously. And they will follow the pattern of cell replication until they take over the world.


The RepRap (Replicating Rapid-prototyper) printer and its “child”.

Maybe that’s a little far-fetched. Machines need to be self-aware first before they will replicate themselves and plot against the humans. So far the best AI I’ve seen is probably a chess playing computer. We’ve still got a long way to go.

Now the interesting thing about RepRap is that it’s open source. That means anyone can own it for free. If I have a RepRap, I can print you one RepRap for free! The goal of the project is to “build more and better RepRaps.”

However, RepRap can only make up to 60% of its parts only. The other 40% like motors, electronic circuits and steel tubings need to be sourced from elsewhere. And human interaction is needed to put the parts together to make a new RepRap. So in a way, it cannot self-replicate and over-run the human population yet. But with the help of robotic arms and printers capable of printing electronic circuits, it just might happen. Currently there are 7 known RepRaps around the world.

Some parts to build a new RepRap.

So what does all this means for us? RepRap, being an open source 3D printer, is very cheap to manufacture. Everyone can now own a 3D printer if they want. But why would you want a 3D printer? Easy, so you can build more 3D printers. With more 3D printers, you’ll be able to make things faster. And the great thing about it is that it doesn’t cost a lot to “replicate” another one.

The completed RepRap.

For more practical applications, take a look at the examples below:

A pair of shoes made by RepRap. It took 1 day to make.

Custom made iPod holder to fit your car.

Make extra shot glasses if you have extra guests coming.

Make spare parts for your other devices when they break down.

The applications are limitless. I can an object on my computer and if you like it, you can instantly print it out using your 3D printer, even if you’re halfway around the world! Now how cool is that. Continue reading

Catch of the Day

Since I live near the airport, I suspect that planes will fly obscenely near my area when coming in for a landing. I got this shot when I was cycling out looking for the perfect sunset.

It was very close. I can hear the 4 turboprops clearly, chopping through the still evening air. Man, I wish I had a Nikon D40 with a 55-200mm lens then.

High-tech bait for fishing. I’ve even seen some bait with those “glow sticks” to attract fishes at night. Continue reading

Saving Our Earth

With the earth warming up rapidly due to increased CO2 emissions, it will only be a matter of time before our earth succumb to global warming. Polar ice caps will melt and low lying areas will be flooded. Plant and animal species will go extinct, unable to cope with the changes to the environment. We’re facing a very grave situation here.

Global warming is caused by CO2 emissions.

There are of course many ways to deal with global warming. The reduction of CO2 output will help to stabilize the CO2 content in the atmosphere. Plants will be able to convert the excess CO2 back into oxygen through photosynthesis. Without the excessive CO2 in the atmosphere the earth’s temperature will slowly return to normal.

But if the amount of CO2 released to the atmosphere cannot be controlled then we need to find a way to take away the CO2 faster than we can produce them. This can be done by planting more trees or creating a device that can extract and store the CO2 elsewhere (e.g. Underground). Inventing a device to store CO2 might not be such a great idea because a machine of such scale will probably require massive amounts of energy to operate. With current technology, such energy is only available through the burning of fossil fuels. That means more CO2 will be released and a waste of energy that can be used for other processes.

What we need is something that will take away CO2 without consuming large amounts of energy. Something that doesn’t require lots of raw material to construct. Something that is self-sustaining and require little maintenance. Something that will not harm the environment.

The answer is pretty obvious. Nature had one of the most efficient air purifiers in the world. Trees. Perfected through million of years of evolution, with the help of sunlight trees will convert CO2 and water into oxygen and food. Not a lot of money is needed to plant trees. After planting, maintenance is minimal. Large trees will last over a century. They don’t pollute, they don’t destroy the environment and when they die, they are 100% recyclable.

Trees blanket the mountains of Langkawi.

So it seems very obvious, no? Our Kedah Menteri Besar Azizan Abdul Razak is doing just the exact opposite. He’s proposing to cut down 1 million trees at the Ulu Muda forest reserve area to increase the government’s coffers to fund development projects. Let me ask you something Menteri Besar. What’s the use of development if people are going to suffer in the future when the environment is destroyed.

If he had said this during 1908, I would have brushed it aside. It’s now freaking 2008! Which century is he living in? Everyone’s planting trees now and addressing environmental issues. Global warming is serious. Didn’t anyone tell him about it? Sure, he might not live long enough to feel the effects of global warming, but he should at least think of his children.

I don’t even know how to explain this. You’re supposed to be preserving the trees.

Development should compliment the environment, not destroy it. It didn’t come as a surprise when local environmental groups and NGOs voiced out against the proposal. The felling of the trees will earn the government RM100 million. In the process, the government has to spend money on felling the trees. Helicopters will be used to lift the trees out after they have been cut to reduce the damage to surrounding areas. I’d like to imagine the cost of lifting 1 million trees using helicopters. And not to mention the 400KM road that has to be constructed to transport the logs out. If the logging activity doesn’t destroy the environment, the building of that road will.

For our sake, I hope this proposal doesn’t go through. Continue reading