Posted May 13, 2012 by Chris

“The basic ingredients are a big felt pen, large enough to host some batteries, a bunch of old CDs forming the flying wheel, an embedded ATmega microcontroller, 8 small SMD LEDs, and some wires. Glue about four CDs together and mount them on the felt pen as shown in the figure.”

Posted May 9, 2012 by Chris

“I mentioned last week that I wanted to have MANOI’s RGB LEDs fade in and out at different rates from different starting points to different ending points. Luckily, it was a pretty easy task to accomplish, so now I can share the code with everyone!”

Posted April 25, 2012 by Chris

“In this post we will study the ADC ( Analog-to-Digital ) Module of the Microcontroller PIC16F917 . We will study a real circuit of PIC16F917 interfacing to a semiconductor Gyroscope.”

Posted April 18, 2012 by Chris

“In this tutorial we will take advantage of PIC18F14K50 pulse steering mode to drive the DC Motor and at the same time we will build the RPM (Rotation per Minute) counter to observe the PWM effect on the DC Motor speed and display it on the 2×16 LCD.”

Posted April 16, 2012 by Chris

“I built a pair of flex sensor gloves for capturing the motion of all ten fingers. This system uses individual flex sensors made by Spectra Symbol and a National Instruments analog capture device to record the flex sensors’ values.”

Posted March 13, 2012 by Chris

“The battery-powered Levitating Digital Scale electromagnetically levitates a load platform, and uses a linear hall-effect sensor to measure the magnetic field strength to determine the weight of the platform. The levitating platform is embedded with a permanent magnet that opposes the magnetic field of a solenoid (the electromagnet). When a load is placed on the platform, the levitating platform will settle to a new height.”

Posted March 9, 2012 by Chris

“To estimate its orientation, Bullet integrates readings from the gyro and accelerometer using a complementary filter. To balance, the angle estimate is fed through a PID loop (with no integral term). The loop runs at 625 Hz. The output from this stage determines the duty cycle of a 1.22 kHz PWM signal, which is connected to the H-bridge. The code was written in C, and is in the public domain.”

Posted February 25, 2012 by Chris

“Each slave normally runs in a infinite loop, sampling the LED sensors as fast as it can and storing their values in a memory buffer. When a polling request is received from the master, an interrupt is generated which branches out of the sampling loop. I2C commands are pretty complex on paper, but merely a matter of setting and clearing bits in the digital world, so at 20mHz the pic handles them with lightning speed.”

Posted February 21, 2012 by Chris

“I decided to build an autonomous flying robot about three years ago. I’ve converted RC cars to autonomous operation, so I thought that an RC helicopter might be a good place to start. I quickly discovered that the standard helicopter design would probably be too unstable in flight for my simple navigational and programming skills – but in searching the web I stumbled across the four rotor electric helicopter platform…and I was hooked!”

Posted February 3, 2012 by Chris

“This Digital code lock can be used for security purposes on doors, cupboards, desks, etc. Once installed it works without any maintenance and there is no need to keep a key. It also shows the time, day and current room temperature on its home screen which is sensed using a LM35 temperature sensor.”