v 2.0 robot not rotating fully (e.g., rotates ~175 deg when I want to rotate 180 deg) | EdScratch programming | Forum

Please consider registering

Log In Register

Register | Lost password?
Advanced Search

— Forum Scope —

— Match —

— Forum Options —

Minimum search word length is 3 characters - maximum search word length is 84 characters

v 2.0 robot not rotating fully (e.g., rotates ~175 deg when I want to rotate 180 deg)
September 2, 2018
12:10 pm
New Member
Forum Posts: 2
Member Since:
September 2, 2018
sp_UserOfflineSmall Offline

I’m not sure how the robot is supposed to detect how many degrees it’s supposed to rotate but in many tests I can’t get them to rotate as much as I want them to. I’ve tried this with two relatively new robots and the results are the same. 

I can demonstrate with this simple program that is supposed to drive the edison forward, turn 180 degrees, and repeat 10 times. Unfortunately, in testing on different hard / smooth surfaces I’m getting the same problem. Instead of turning 180 deg, the robot turns 175 or so. Not fun.

program to test whether the robot turns less than specifiedImage Enlarger

This (and my previous topic) I noticed when writing what should be a simple program that makes the edison drive along the path of a regular polygon. Give an input (round button) and it would increment the number of sides the robot would draw, while decrementing the angle (e.g., draw 2 sides, 360/2 = 180 deg turns; 3 sides, 360/3 = 120 deg turns; 4 sides, 360/4 = 90 deg turns …)

Anyway, hope there is a firmware solution to this. I figured the current implementation could compensate for wheel slip or worn motors because they are supposed to detect amount of rotation somehow. Also I would assume the distance detection would work similarly. For the time being I’ll have to manually compensate for the robot’s lack of turning (e.g, “spin 190 degrees” to make the robot spin 180.



September 3, 2018
9:15 am
Forum Posts: 180
Member Since:
August 24, 2015
sp_UserOfflineSmall Offline

Hi Dave,

Due to minor mechanical differences in the motors and encoders inside different Edison robots, some robots may not turn to exactly 90 degrees when given the input of 90. Encourage students to try different values around 90 (e.g. 87 or 93) to find the input that works best for their Edison.

When using programs that run multiple ‘drive’ commands consecutively, students may note that their Edison robot’s accuracy is reduced as more and more commands run. Adding a pause (using either a ‘wait’ with a very short input value or a ‘stop motors’ block as appropriate) between ‘drive’ commands allows the motors to fully stop moving, which will increase accuracy.

  • Keep up with Edison

    Sign up for our newsletter to get all things Edison delivered straight to your inbox.

  • This field is for validation purposes and should be left unchanged.

Heads up

The Australian Federal Parliament has passed a law that extends goods and services tax (GST) to low value imports of physical goods imported by consumers from 1 July 2018.

This means that all customers purchasing Edison robots and accessories with an Australian shipping address must now pay GST. The GST will be automatically added to your purchase and show as a line item on your invoice.

We've detected that you are in Australia, so we wanted to let you know that we have changed your settings to view our Australian site, which displays GST inclusive pricing.

You can change back to the GLOBAL SITE at any time using the link in the top left of the page.

OK got it!    Take me to the GLOBAL SITE instead


Pin It on Pinterest

Share This