AVC: Precision Gyro Calibration Reloaded

Here's the updated 2012 version of the gyro calibration I performed on Data Bus in 2011.

The goal as before is improved heading accuracy. Target: L3G4200D on a Pololu minIMU-9.

Last time I used my "high precision rate gyro calibrator," a 1970's Realistic Lab-400 Direct Drive turntable. I used it again this time. I also used by gyro/magnetometer calibration machine.

High Precision Gyro Rate Calibrator

Gyro/Magnetometer calibraiton machine.

Alright then. Let's get on with it...

AVC: Initial Data Logging

Data Bus prepares for a nighttime logging mission

After all these many months Data Bus finally logged some real world data! What excitement! Two weeks away from the big demo! Eek!

Why'd I wait so long to run the robot in the real world? I wanted to take my time understanding the problem better than I did last time so I would be, hopefully, less surprised by the results and closer to a working solution.

Here are the results of three separate runs, driving the robot around slowly outside the house AND two runs at Sparkfun!

Road Testing an ARM LPC2101: Part 1a

In the previous article, I soldered an LPC2101 onto a Schmartboard for testing. The low cost ARM7 MCU was sent by Newark to me for road testing. Part 2 was intended to discuss programming the device, but programming turned out to be substantially more involved than I expected.

LPC2101/2/3 Breakout

Meanwhile, the chip fried during experimentation, halting my progress. I subsequently designed a breakout board for the LPC 210x family of MCUs and assembled the first set of parts onto one of the boards to try it out.

Downloading a hex file to blink an LED was successful!

I've also successfully programmed the UART and sent "Hello World" over serial. Cool!

Features:

• Compact 36-DIP package for breadboard prototyping
• Uses standard FTDI 6-pin header for bootloader programming and serial debug
• Program switch makes it easy to flash new programs via bootloader
• 800mA 3.3V onboard regulator to power MCU and attached circuits
• Onboard 1.8V regulator reduces power complexity for the experimenter
• Three supply options: FTDI, VIN pin, or external 3.3V supply
• Reset switch
• Debug jumper
• Pin 0.14 is exposed for automatic program mode with RTS

Eagle Files

The board's Open Source Hardware so here are the Eagle files, Gerbers, etc.:
http://code.google.com/p/bt-arm-breakout

Coming Soon

This new development platform and the switch to an LPC2103 made it easier to get sample programs working.

The ARM7 is a bit tricky to get started with because one must include startup code in assembly with the chip to set up the stack and other configurations.

One must also set up a memory map within the IDE. More details to follow in Part 2, coming soon.

Eventually, I will undertake a similar road test for a Texas Instruments ARM processor, also sent by Newark for road testing. Stay tuned!