servo motor

[hamid9543]

hi
i want to drive 2 servo motor synchronise.2 servo motor (both) move forward or move backward by pic16f877.
hard ware:
 servo motor  (2)
  pic16f877     (1)
software:
picbasic pro

[chandra2sekhar2000]

hello hamid
just connect the control signal of both the servos to single out put of pic.
later on i will try to provide u the code

[hamid9543]

hello chandra2sekhar2000
thanks for yor help.can you explain more about this

[hansariii]

hello
you need to create a square wave with 1 to 2 ms on for signal pin

[chandra2sekhar2000]

sorry for late
i hope the given circuit may explain u.

[mcr]

Use the pulsout command.

Haven't used any servos my self but on many books the use the pulsout command.

Make a quick search on the web, lots of examples (to bad we can not provide links to other forums).

[iphone]

sorry for late
i hope the given circuit may explain u.

chandra2sekhar2000,

Can you share the sourcecode as for starting point ?

Thanks

[hamid9543]

thanks
very good

[sherm]

You can use the PULSOUT command in PBP to control a servo very easily.

Connect the control line of the servo to RB0 and a centre off SPDT switch wired as active low to pins RA0 and RA1. That'll act as a direction control for your experiment. The following code should give you a good starting point. Adding an extra servo and different control method will be easy after this

Code:

bPos var byte
bPos = 150          'Centre position

loop:
  if PortA.0 = 0 then rotA
  if PortA.1 = 0 then rotB
  pulsout PortB.0, bPos
  goto loop

rotA:
  bPos = bPos + 1
  pulsout PortB.0, bPos
  pause 18
  if bPos > 200 then limitA
  goto loop

rotB:
  bPos = bPos - 1
  pulsout PortB.0, bPos
  pause 18
  if bPos < 100 then limitB
  goto loop

limitA:
  bPos = 200     'direction limit
  goto loop

limitB:
  bPos = 100     'direction limit
  goto loop

This code could be re-written far more efficiently, but it's laid out so that it's easy to understand the process of working with servo's. There's a wealth of information available on the subject if you do a Google search. This should get you started though.

Good luck

[engr.humair]

Read the PULSIN & PULSOUT function in PBP Manual.They will do the job

[Deimos]

Look at here:

http://www.sonsivri.com/forum/index.php?topic=6901.0

you can use this code, changing the potenciometers by using four push buttons.

[Upgraded]

Don't power the servos (R/C-servos?) from the same supply as the microcontroller. Servos draw quite a bit of current, and will induce spikes that makes the PIC go funny.

[picza]

If i want to control 3 dc-motor together.how should i do? and will i use with Chip l239d for 2IC?

[Deimos]

You can use one L293 for controlling two dc-motor, if you want to controll trhee, you need two L293, what do you mean with 2IC?

I2C is a protocoll, you can use PWM to controll the speed of the motors.

PD: the topic is about SERVOMOTORS.

[alsabbag]

I2C Protocol is used to connect multiple devices together. I don't think it is required for controlling servo motors. PulseOut command can help providing control to 3 servo motors knowing that step duration is much larger than single instruction cycle making the difference in motors start time negligable.

[anemon06]

step and servo motor application include picbasic and proteus schematic

[yobalzal]

I hope this will help. Once testing motors controlling experiment, I killed two microcontrollers by the back emf from motors, I found a very simple technique, just put a 100 ohms resistor and a 5V zener diode to protect the micros. It did help a lot.

Cheers...