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Canada
Asked — Edited

Questions About Movement Script And Ping Sensor

Hi All,
I've now played with all the equipment that came in the robot build kit and having a great time of it. I made a little proof of concept bot on the super cheap. I used a free paint stir stick from hardware store as his chassis, so I've named the little guy stirstick 1:)

I have some questions about the ping sensor and the movement scripts.

1. Does the ping sensor draw a lot of power? When I start up either a radar scan or Ping collision control it causes the blue LED on the EZ-B to start blinking slightly. I'm using a 7.2 volt NiMH battery. Would a higher voltage batter help this. I also noticed that if increase the scan interval in the radar control to 150 ms that it is visual speedier for only a few ticks of movement then will slow down to what seems closer to the 250-500 ms setting is.
2. Next I used a modified servo control for the drive servos and added a movement script to control the steering servo of a rear wheel. When I use the Movement Panel controls it works nicely, however if I check the collision avoidance in the radar control the rear wheel will not steer even though the movement control is steering the modified drive servos. I am wondering if I am using this incorrectly, or this just something that isn't part of the radar movement control.
3. Regarding the collision avoidance in the Radar control, the bot always moves to the right is this something that can be changed or do you use scripting for this as well.

I created a small movie (1.5 minutes) to demonstrate the questions I have:

http://youtu.be/iNXS0UMxUD8

I also am curious about the port plugs above and below D14 and what these are used for and also the port on the left side of the board with the 3.3 v and 5 v headers?

Thanks for any help

Chris
EZ-B fan!

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#2  
1) the led flickers everytime a command is sent. that's expected behaviour

2) the movement script probably doesn't have enough time to respond to the radar control. the radar control has MS delays, and the servo for steering won't respond quick enough. you would have to create your own script for object avoidance.

3) what ports below d14?

4) the port on the left with the 3.3v and 5v headers are for devices that require 3v.

Glad to hear you are a fan of ez-robot:D your robot is pretty cool! very original
#3  
Great bot:) Why not just let the rear wheel work like a caster and free wheel it.
Do you have two drive wheels up front? if so then set them up with independent forward and reverse.

I just watched your video again and noticed that you do have differential drive so basically a ball on the back would work too.
Canada
#4  
Hi DJ and Putt Putt,
Thanks for the feedback

DJ:
#1 good to know I don't need a bigger battery
#2 Would it be better to use a script with the Ping collision, seems simpler. Or is there a way with the Radar control ( I love this control )
#3 Above D14 is a 2 pin header and labeled EXT PWR, is this for running servos off of a separate battery? Just below D14 is labeled GND. Are all pins Gnd or just the inside one?
#4 there is also a Vin and something else I can't make out (marked it up in image) so I thought this was another type of communication port.
User-inserted image



Putt Putt, that is how I orignally had it setup with out a servo. Seemed to drag a lot so I had a spare servo from a plane or something so I gave it a try. I was also a excuse to try a script out. I'm curious to see if I was just to leave the Movement Panel config for Servos as NA and write in values into the movement script control what I would get. Probably give it a shot tonight after my baby boy goes to bed.
It is just a proof of concept bot... just using what I have lying around. Have bigger plans for this awesome board:)
#5  
Hi SIRLAL,

Love your bot. Very cool. Great vid too.

I am glad you brought up the movement script. I am also using one. I have a tracked robot with an H bridge motor controller. Due to the way the H bridge behaves I have to write scripts for forward, reverse, left and right. Each script has 4 simple 'set' digital commands to set the polarity of the motors and then turn them on. I set up the movement script to Controlcommand('Forward",startscipt) (example) for each line in the Movement Panel (is this what you did?)

I am noticing similar behavior that you are noticing and some undesired effects when I tell the radar control to take control of the Movement Panel (in my case movement script). (simply does not seem to respond correctly). For example if i turn on 'control movement panel' and 'reverse before turn' the bot stops at the threshold ping reverses and does not stop.

DJ indicates your issue may be a timing issue. DJ, Could I be experiencing the same thing? Any way to slow things down to accommodate my movement script and still use the radar or is the best answer the object avoidance scripting?

v/r

Kevin