The Sharkbot-Arduino Mega link

Fifteen-year-old Angad Daryani has developed a number of open source projects in recent years, including an e-reader for the blind, a solar-powered boat, an automated gardening system (Garduino) and Sharkbot, a 3D printer powered by the Atmel-based Arduino Mega (ATmega1280).

Daryani, who is also the co-founder of Makers Asylum in Mumbai, recently told DNA that he plans on making SharkBot the most affordable 3D printer in India.

“We have designed almost every part ourselves. We will have different models of SharkBot at different prices- but the goal is to sell 3D printers and expose everyone to 3D printing at a very low cost,” he explained.

 “The logistics and business of Sharkbot will be handled by my dad’s nationwide computer peripherals company – Kunhar Peripherals. We have offices all over the country and thus we are looking at creating a nationwide revolution.”

Daryani also noted that he specifically chose an Arduino Mega to power the SharkBot.

“One needs a lot of I/O pins for a 3D printer. [You] need pins to drive 4-5 stepper motors, 2 mosphets, a graphic lcd, a digital encoder and several other sensors and switches,” he said. “The board we have developed is an all in one, single sided PCB board for 2,000 INR. It’s [specifically designed to] control 3D printers.”

Last, but certainly not least, Daryani emphasized that he will not be only be focusing on the SharkBot, but rather, looking to create a Maker Movement revolution in India.

“Everything that I make, is open sourced so that everyone else can learn how it works or re-make it,” he concluded.

ATmega32 in your home-built DNA sequencer

The May 2013 issue of Circuit Cellar magazine has a great article by Fergus Dixon, who uses an Atmel ATmega32 microcontroller to operate a DNA sequencer.

One of the dozen ways to sequence DNA is to apply a reagent to the DNA sample. If the reagent reacts with the base pair on the end of the DNA strand it splits the pair and emits a tiny burst of light. If it is a double pair the burst of light is twice as strong. Then you just work your way up the DNA strand “zipper,” breaking the pairs and recording which of the 4 pairs you just broke. Now you understand why it took years to sequence even a short DNA strand.

Here is a control board from a DNA sequencer designed by Fergus Dixon

Fergus had the usual engineering fun you might expect when doing something this cool. The flat-black box he housed the light sensor in had a tiny hole. Light variance in the room showed up as noise. He had to figure out a method to drive stepper motors so they were smooth and got to 3000 RPM. He designed reagent solenoid injector drivers that worked off of 100V pulses, while also fiddling with the SPI ports. My consultant buddy John Haggis swears that any serial interface will take up 6-person months of labor.

I used to laugh at that – but I now think he is right. You have to get the hardware working, develop protocols, test for exception conditions – yeah, I can see six months just getting two devices to talk to each other.

You can see that Circuit Cellar has some great articles. The same May 2013 issue has an article on a wi-fi connected energy monitor, a serial port to SPI programmer, a G-code CNC router, a MIDI communication device, and a reprint of a radiation monitor – like a Geiger counter.

Now I can’t show you these articles on-line, since Circuit Cellar is a print magazine. And you have to give them 50 bucks a year to get it. You can get it as a digital pdf if you want to save trees. Its $85 a year for the both print and digital versions. There are large discounts for two- or three-year subscriptions. Best of all, you can give them something like $225 and get every single issue in history on a thumb drive. Then with your combo subscription you can add your monthly pdf to the archive thumb drive, and still have the print edition to impress your friends and boss.