PIC Chip & Analog Joystick ?

[Mr.Cool]

mixing joystick outputs

i was just wondering if anyone can point me to a web site or can provide advice for a project i am doing. i have an analog joystick. i wish to control 2 motors with this joystick. i have the motor control hardware done. simple H-Bridge circuit. now i must provide a PWM signal to the legs of the H-Bridge. i would like to use the PIC 16F877 because i get them free and cause they have ability for PWM output.

my input comes from an analog joystick. This is what i was thinking. Connect Y-Axis resistor between +Vcc ang GND. add a series resistor following this formula:
Joystick Series Resistor = (+Vcc/.02) and 10K - (Joystick R)/2

input this analog signal into 16F877 A/D input.

do the same for the X-Axis input.

now i need software to do channel mixing such that ONE joystick can control 2 motors. preferably i would like this code in Pic Basic or Assembly.

thx for any help you can provide

Mr.Cool

 

[Mr.Cool]

joystick pwm output

code examples in 16F84 or 16F84A would also be acceptable

Mr.Cool

 

[petarpav]

analog joystick circuit diagram

Look Application note for Siemens GMR sensors.

 

[Mr.Cool]

picbasic joystic

here i find an excellent example of taking ANY analog 2 axis joystick (single stick) and convert it to a serial ouput. not quite what i was looking for. i do not want a serial output. i need a PWM output. but contained within the serial output is the PWM signal. perhaps i can decifer this information with another 16F84 chip. time will tell. also using proteus would be a great help in this mannor.

h**p://www.seetron.com/guest/berg/berg_joyssc.htm

Mr.Cool

 

[meax98]

dual axis rc joysticks

This is what you are looking for:

http://www.rentron.com/ruf-bot.htm

regards
meax98

 

[Mr.Cool]

3 axis analog joystick

yes i have found this article. it is EXACTLY what i am looking for. except that the author does not finish the example code. the author produces the direction signal, but not the PWM speed control.

how can i modify this code to get the desired response? i need this circuit to control 2 motors


Mr.Cool

 

[Mr.Cool]

resistor joystick

i could use the code as is, minus the parts about serial communication.

then to achieve PWM i could take the values stored for X-Axis and Y-Axis and mix them. coincidentally i just read a post elsewhere on this subject.

Right Motor = X + Y - 255
Left Motor = X + Y

limit output to +/- 127

now, i need to see how i can get 2 PWM outputs using the 16F84! any tips?

Mr.Cool

 

[Mr.Cool]

2 axis joystick chip

quick question.

the schematic you posted shows the X/Y-AXIS connected through a polarized cap to ground. what would a good value be?

also, there is no power supply on this section. look the X/Y-AXIS wires simply floating free... they don't go anywhere. is this right???

Mr.Cool

 

[meax98]

analog joystick motor control

Author try to form voltage devider and on pic side is using picbasic POT command. So, X and Y axis must be connected to +5V. Used caps are 0.1 uF.
Command is like this:

POT pin,scale,variable

Measures resistance on "pin" by timing the discharge of a capacitor through the resistor (typ 5k-50k). "Scale" (1-255) is used to adjust for varying RC constants. If "scale" is set correctly, than "variable" is zero near minimum resistance and 255 near maximum resistance.

regards
meax98

 

[tonykeys]

rc joystick with pic

This is the circuit diagram. this is for half of the circuit the other half will be the same. i've shown switches for the joystick fwd & aft. Hope this helps. Many thanks