nCode's Blog

Good afternoon,

When working on my sentry project a while ago I found a problem with the serial delay values in the Arduino Softare Serial library. This was causing a problem when I was trying to send commands to the pololu dc motor controller at 9600 baud.

After some debugging and with the help of an oscilloscope I noticed that the following values were too short:

#define bit9600Delay 84
#define halfBit9600Delay 42

And should be changed to:

#define bit9600Delay 104
#define halfBit9600Delay 52

Cheers,
Marc

Came across a site with quotes the other day:
http://www.devtopics.com/101-great-computer-programming-quotes/

Here are some quotes I think are really good:

“If the automobile had followed the same development cycle as the computer, a Rolls-Royce would today cost $100, get a million miles per gallon, and explode once a year, killing everyone inside.”
(Robert X. Cringely)

“Programmers are in a race with the Universe to create bigger and better idiot-proof programs, while the Universe is trying to create bigger and better idiots. So far the Universe is winning.”
(Rich Cook)

Look at the site for more!

Good afternoon!

Project ARCHA stands for Automated Remote Controlled Helicopter Assistant

The goal is to facilitate and improve control of an helicopter (E-Sky Honey Bee CP2) by adding a micro controller and various sensors to have it flyable by an inexperienced pilot.

*Please note that RC Helicopters can be dangerous, you could very well cut yourself, get hurt, injured, etc. You really should try to understand the source codes and schematics before trying to reproduce anything you will find in this project*

Project Outline

• Phase 1
  • Select a micro controller
    • Arduino Mini Microcontroller Module
      • Has 6 x ~490 Hz PWM pins
      • 14 digital IO
      • 6 analog Input (10 bit dac)
      • more details
  • Build powersupply for the micro controller, servos and additional electronics
    • 2x 7805 will provide 5volts 2x 2 servo motors
    • 1x 7805 will provide 5volts to the controller, sensors, wireless receiver, etc
    • a 3.3volt regulator will power the dual axis gyro + 3 axis accelerometer IMU
    • The DC motors will be powered directly by the LiPo battery
  • Hack a PPM signal from a 6 Channel RC Receiver
    • 6 Channel 72 mhz SunUP SU/R-6FM bought from ebay
  • Read and interpret the PPM signal using the controller
  • Build a battery voltage meter using a voltage divider
    • It is not safe to drain a Li-Po battery too much… according to various posts on rcgroups.com and heliguy.com usually around 10-10.1v is a good time to recharge it
  • Build a main rotor and tail rotor dc motor pwm controller
  • Select a servo controller
    • external servo controller will reduce stress on the microcontroller
    • will use Pololu Micro Servo Controller
  • Build algorithm to control the servo motors and dc motors from the ppm signal
  • Interface MLX90609 gyro with the arduino, will be used as the tail gyroscope
  • *The helicopter should be flyable at this point*
• Phase 2
  • Interface the Sparkfun 5DOF IMU with the Arduino via a MCP3208 12bit ADC
  • Modify algorithm to calibrate and take into account the gyro’s and accelerometer’s feedback to stabilize the helicopter in flight
  • Tune the Kalman Filtering in order to get a clear pan/tilt measure from the 3 gyro + 3 accelerometers cluster (6 degrees of freedom)
• Phase 3
  • Mount and connect a memory card that will be used for flight data storage
• Phase 4
  • Mount and connect a gps module
  • Modify algorithm to save the gps data in the memory card
• Phase 5
  • Modify algorithm so the helicopter can follow pre-programmed gps waypoints

Work Progress

• Remote Control – E-Sky EK2-0406A Mode 2 (Left Throttle)
• Voltage Divider / Battery Meter Circuit
• Receiver PPM hack – 6 Channel 72 mhz SunUP SU/R-6FM
• Pololu Micro Serial Servo Controller Problem/Bug with the Arduino
• UTC LP2950 Voltage Regulator Pinout
• Prototype: Completed
• Interactive View of the Prototype Board (updated september 4th)
• Firmware Version 1.0 Alpha
• PROBLEM! During testing I found out that my ground and +5v is getting really strong interference from the 72mhz ESky controller I’m using, I will test the following:
  • Adding extra ceramic capacitors
  • Wrapping the main circuit board with a Faraday cage
• After experiencing with capacitors and various noise filtering solution I am still having the noise problem that cause a huge fluctuation in my 5volt signals. I will post in a few days/weeks a solution involving 2x XBee Pro 60mW 2.4ghz 1miles range modules link to XBee Pro Manual.
  • One will be connected on an arduino connected to the remote control’s trainer port.
  • The second xbee will be mounted on the helicopter and connected to IO pins 0 and 1 of the arduino mini.
  • This will give us bi-directional communication between the remote control and the helicopter, an lcd display will be mounted on the remote to display feedback and status from the helicopter.
• Currently waiting for 5dof accelerometer + gyro imu from sparkfun so I can finish the helicopter part, when this is finished I will work on the controller part with the xbee pro modules, mounted LCD screen and keypad connected to the E-Sky RC Helicopter Controller.
• First video of the prototype with the recently added 5dof module here.

Picture of the prototype board mounted on the Honey Bee CP2 RC Helicopter: (click to enlarge)

Revised on October 16th at 08:20 AM by Marc Vieira Cardinal

Every significant Internet provider around the globe is currently in talks with access and content providers to transform the internet into a television-like medium: no more freedom, you pay for a small commercial package of sites you can visit and you’ll have to pay for seperate subscriptions for every site that’s not in the package.

Source: http://ipower.ning.com/netneutrality

Would the CRTC really let that happen?

Good morning,

These days we worry about gas prices… gas is getting rare… we’ll be out of gas… but what would we become if we ran out of elements? the raw material of the universe?

I came across the following article: http://www.asimovs.com/_issue_0806/ref.shtml

Cheers,

Marc