MiniStamp project Accelerometer Help

Ronbert

I'm working on the mini stamp project for inclining sensing with an accelerometer. I'm at the portion were the boe bot should be driving in a rectangle but instead it just goes in complete circles. Why would this be?

This is the project I'm refering to: http://forums.parallax.com/showthread.php/76732-Boe-Bot®-Robot-Navigation-with-Accelerometer-Incline-Sensing

EepromNavigationWithRamping.bs2 is the section I'm working on. I can't figure out the problem here. I can't attach my code because to my unfortunate dismay I lost my flash drive.... but I've checked over and over again and verified the code is 100% the same as the tutorial/mini project.

Genetix

Check if both wheels turn when the BOE-Bot moves and weak batteries are known to cause all kinds of servo issues.

Ronbert

Both wheels turn in opposite directions actually. Something must be wrong here.

Courtney Jacobs

Have you made sure that your servos are centered properly?

Ronbert

Yup! I just changed the batteries now to be sure they are fresh, I also ran the calibration code to make sure the acceleromoter measure on the axis properly and double verified my wiring schematic. I'm just not sure what the problem here is.

Genetix

You didn't answer Courtney's question about centering your servos. Also post your code.

Ronbert

I did answer Courtney's question I also can't post the original code, see original post for why. I have tried writing the code for going uphill (from the same page) and that too has the never ending circle problem. I will attach code for that.

I just want to reittirate that I have double checked the wiring schem and I've unplugged ALL exterior attachments in order to use pins 6 and 7 to ensure the code is perfect.

EDIT: For the purposes of this thread I've rewritten the EEPROM navigation code and am still having the same problem... code attached.

EDIT2: Okay, I'm not sure why but suddenly the code works. First two times I ran the code and the bot just turned in a 360 over and over again. Third time it did the full rectangle. I'm sure the batteries were fresh, Odd.

Genetix

Did you calibrate the servos or the accelerometer?

Try a program such as BoeBotForwardThreeSeconds.bs2 from Robotics with the BOE-Bot.

Ronbert

The servos and accelerometer have been calibrated. I still havn't discovered what caused the program to work suddenly but everything has been fine since.

Genetix

Intermittent problems are very annoying.
Give all your wires and parts a wiggle and see if anything changes. Also make sure the wires and parts are fully inserted into the breadboard.

Genetix

The instructions for EepromNavigationWithRamping.bs2 say:
Verify that the Boe-Bot starts out by moving forward.· Depending on your servos, it may curve to the left or the right a little, which is okay.·
Fine tune the distances so that they make your Boe-Bot travel in a rectangle.· The turn at the first corner should be left, 90°.· The second should be right, 270°, and the third should be another left at 90°.
The distances are stored in the DATA statement under EEPROM Data
·
UphillBoeBot.bs2 has several errors in it:
'Initialization
FREQOUT 4, 2000, 3000 ' Program had 500 instead of 2000

'Navigation decisions
IF ABS(x) > 40 THEN
pulseLeft = 750 - x ' Program had +

'Increment/decrement routine
IF pulseLeft >
IF pulseLeft < (pulseLeftOld - 8) THEN pulseLeft = pulseLeftOld - 8 ' Program had >
IF pulseRight >
IF pulseRight < (pulseRightOld -8) THEN pulseRight = pulseRightOld - 8 ' Program had >

All the code can be downloaded from here:
http://learn.parallax.com/project/boe-bot-robot-navigation-accelerometer-incline-sensing