How to make a cell phone step by step

Our reporter builds a handcrafted cellphone using
widely available parts and online instructions
SUDDENLY, my phone rings. It chirps out a tinny
version of what sounds like the Christmas carol Angels
We Have Heard on High . I am giddy with amazement.
On the fifth floor of the MIT Media Lab in Cambridge,
Massachusetts, David Mellis has just plugged in the
mobile phone I spent all afternoon soldering together.
That's right: I just built a cellphone. By hand.
Mellis is a graduate student in the High-Low Tech lab, a
group of engineering evangelists trying to bring
technology know-how to people who perhaps thought
it was out of reach. In 2005, he helped found Arduino ,
a company that makes easy-to-program
microprocessors and sells them on simple circuit
boards. The idea is to help people make electronic
products without needing a degree in computer
science.
They're popular among hobbyists, hackers and the sort
of people who end up working at the Media Lab but
they're hardly mainstream. Mellis wondered if he could
take the idea further.
"The tricky thing is getting it beyond the people who
are already doing electronics stuff," he says. So he
decided to see if he could design consumer electronics
that you can make yourself and actually use. He started
with radios, speakers and computer mice before
making the leap to the ultimate consumer device: the
cellphone .
Mellis shows me how to melt the soft metal solder onto
the circuit board he designed and how to use the metal
to attach resistors and capacitors about the size of a
few grains of salt. I'm nervous at first – I've never
soldered anything in my life. That makes me a good test
subject, Mellis says.
"I'm interested in trying to open up the process to
people who haven't really done this stuff before," he
says.
Soldering felt a little like doing a colour-by-numbers
painting – I was filling in spaces on the circuit board,
but my understanding of how the parts fit together was
pretty sparse. And a lot of components were still out of
my control. I used Mellis's software, for instance, which
gives the phone capabilities similar to that of a 10-year-
old Nokia phone: it can make and receive calls and
texts, store up to 255 phone numbers, and has a clock.
The whole thing costs about $100 in parts, excluding
the SIM card. Nearly all of the components came from
online electronics or hobbyist shops, he says, and the
instructions and source code are available on his
website . However, the GSM module, which connects the
phone to the cellular network and translates audio
signals to the speaker and microphone, came from a
Chinese e-commerce website.
The back of the phone has spaces for working parts: the
GSM module; a microcontroller, which brings signals
from the GSM module to the buttons and screen; a
matchstick-sized antenna; and a SIM card holder.
I bought the SIM card, with its month-to-month data-
free plan, from the T Mobile store – connecting to the
network is one thing I can't do myself.
When it was time to laser cut the case, I used Mellis's
designs. That means my phone is identical to his
prototype, which he has been using as his mobile
phone for the past three months. The end result is a
little coarse and chunky, but ends up about the size and
thickness of my Android smartphone. I'm already
thinking of ways to make it my own. I could knit it a
case. I could paint it. I could design a new cover and
have it laser cut myself.
I'm also thinking of ways I could use it. One of Mellis's
labmates wants to make a phone with a single button
for his grandma to call him. Another says that if she
ever has kids, she'll give them a phone that only calls
her.
I'm not ready to throw away my smartphone just yet.
But I might start taking this phone on holiday, so I can
escape Facebook and email but still make calls. And
because I built it, I'm starting to grow quite attached