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France
Asked — Edited

Analog Motor Speed With Joystick ?

Hello,
  I do not know if the subject has already been treated.

I buy a 2X5 sabertooth I configure like this: http://www.ez-robot.com/Tutorials/Help.aspx?id=173
I control my motors with a joystick gamepad with the joystick panel, it works.
The problem is that it is all or nothing: the motors run in full speed or not run.
I will wish that I push the joystick a little, the engines run slowly and more quickly when I push the joystick away.
A kind of analog response in fact.

Does anyone have an idea of ??configuration?


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United Kingdom
#1  
The sabertooth uses Simple Serial for control. Basically a command of 1-127 will drive the motor forwards and 128-255 will drive it in reverse. 0 will stop it.

So what you need to do is use the Joystick variables to change the SendSerial command.

Code:

SendSerial( digitalPort, baudRate, data, ... )


So you change the data to suit. You can use EZ-Script to get the Joystick variable and convert it to a number between 1 and 127 for forwards, depending on the Y value of the joystick, or 128 and 255 if reverse.

I don't have a Sabertooth to play with so can't really offer much more than that. The documentation I just read wasn't exactly great since it said it's 1-127 for forward and 1-127 for reverse too...

But some code example, which needs to be adjusted to suit (I also don't have ARC to hand so my joystick variable may be wrong);

Code:


:start
# Convert the current joystick position to sabertooth command
# Joystick variable 0 to 100 (check this) therefore each increment equals 1.27 on the sabertooth
$sabertoothcmd = $JoystickY*1.27
# Round the number to an integer for the sabertooth
$sabertoothcmd = Round($sabertoothcmd,0)
# Send the command to the sabertooth
SendSerial(D0, 9800, $sabertoothcmd)
# Wait for the joystick to move before proceeding
WaitForChange($JoystickY)
# Loop back to the begining
Goto(start)


Something like that.

Of course, there may be a place in the joystick control for putting the script which may remove some of the code, without ARC I am unsure as I don't use a joystick so have limited knowledge on that part.
#2  
Thanks, i will explore this idea !:)
#3  
I use a 2X12 Sabertooth and it works great. On the dip switch I have 1,3 & 6 on. I see Rich has a good example of a control script, he uses different numbers than I use though. Maybe he has documentation for a single motor drive. On mine it is Motor 1: 1 is full reverse, 64 is stop and 127 is full forward. Motor 2: 128 is full reverse, 192 is stop and 255 is full forward. So in Riches example I would add another speed for Motor 2 i.e SendSerial(D0, 9800, $sabertoothcmd, $Motor2speedcomand) ,also my baud rate is 38400. I know I don't have the same one your using but if you get in a bind my setup may help. Good luck!
United Kingdom
#4  
I have no documentation, my script was an example and needs adjusting to suit.

Your numbers (@purple) are probably the correct ones:)
#5  
Use a script for control motors with the joystick works but there is a response time, lack of reactivité

After several tries, the simplest was to configure my sabertooth in R/C and configure the joystick setting in "joystick servo control"
It works perfectly:)
And I chosen the speed maximal of motor by adjusting the min and max servo position in Joystick setting.

What I shall like making, it is to be able to modify these min and max servo position via a script: when I will press on a button of my gamepad, it makes pass in mode "superior speed "

Have you an idea for this ?