controller help

science_geek

im working on using an atari controller to control a boe bot, but when ever i push a button it does what i want until i let go then i jitters and moves backwards, heres my code

·········· ' {$STAMP BS2}
' {$PBASIC 2.5}
DEBUG "test", CR,
····· "on ",CR
DO
IF (IN0 = 1 ) THEN
PULSOUT 12, 650
PULSOUT 13,850
PAUSE 50
ELSEIF (IN1 = 1) THEN
PULSOUT 12, 850
PULSOUT 13, 650
PAUSE 50
ELSEIF (IN2 = 1) THEN
PULSOUT 12, 650
PAUSE 50
ELSEIF ( IN0 = 0 AND IN1 = 0 AND IN2 = 0 AND IN3 = 0 AND IN4 = 0) THEN
PAUSE 100
ENDIF
LOOP

Unsoundcode

Hi sg, try removing all the pauses , then adjust the last part of the code to look like this

pulsout 12,750

pulsout 13,750

endif

pause 20

loop

you need to keep refreshing the servo, when you release the button there is no refresh the way it is. You also need to command them to the neutral position (750).

Jeff T.

Edit sorry I should say your refresh rate is too long you need around 20 - 30 mS

science_geek

ive added what you said to do and its still not working, so i re-wrote it so that it would tell me what it was doing in the debug window and it will jump around from forward to backward(those are the only two i am trying hard to get right now) it will start out at neutral, then i hit a switch (forward for example) and it will say forward, but as soon as i let off it will jump to backward and then it will jump back around to all the other commands

Dgswaner

I like to break out my commands to subroutines, that way when I get down the road adding sensors or what ever it's easier to "GOSUB" a command. than to retype the multiple lines to get it to do something How about something like this:

' {$STAMP BS2sx}
' {$PBASIC 2.5}

Main:

IF (IN0 = 1 ) THEN GOSUB forward
IF (IN1 = 1 ) THEN GOSUB Backwards
IF (IN2 = 1 ) THEN GOSUB Left
IF (IN3 = 1 ) THEN GOSUB Right
GOSUB Halt
GOTO Main

Forward:
PULSOUT 12, 650
PULSOUT 13,850
PAUSE 50
RETURN

Backwards:
PULSOUT 12, 850
PULSOUT 13, 650
PAUSE 50
RETURN

Left:
PULSOUT 12, 650
PAUSE 50
RETURN

Right:
PULSOUT 13, 650
PAUSE 50
RETURN

Halt:
LOW 12
LOW 13
RETURN

You'll have to modify the code slightly, I'm not sure if I have the left and right mixed up or not. Rather than sending out a neutral freq. to the servos I'd set there lines low stopping the servo completely.
----EDIT

---

it might be better to set 12 and 13 to inputs rather than low. just in case.

Halt:
INPUT 12
INPUT 13
pause 20
RETURN

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A complex design is the sign of an inferior designer. - Jamie Hyneman

Post Edited (Dgswaner) : 5/20/2007 4:34:29 AM GMT

Franklin

Make sure all your pins have pull down resistors to force the pins to 0 when not activated.

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- Stephen

science_geek

what do you mean by pull down resistors

Uncanday

I means a resistor in the range of, say, 47k which conducts just enough to discharge the input capacitance of the pin when there is nothing else driving it. If the controller just has a switch which shorts to Vcc, when all the switches are open the pins are then floating, and what they will see is whatever the capacitative charge is.

HTH

Duncan

bennettdan

How do you have a wiring diagram you can provide as to how you have it hooked to the Joystick.

science_geek

this is basicly what i have ive tried alternating the V pins with no luck


·
· vdd
· ······!
······· !
O/ O
······················· ······················· ··········· ····························· ·!
······················· ······················· ··········· ····························· ·!
······················· ······················· ········································ ·pin 0············

i cant seem to upload the picture but heres a crude example wher i have vdd going threw a switch and into pin 0 i did try putting resistors in and it didnt completely cure it it still would shake and sometimes take off backwards but it did seem to help, i tried putting bigger and smaller resistors but the smaller would make it shake more, and the bigger would make it not shake as much but it would do really weird stuff that i cant explain

agfa

science_geek,

lots of good advice here.· I just wanted to add the results of my experience with the boe bot and the servos.

First, using the debug statements are an excelent way of troubleshooting.· It sounds that you do have a problem with the joystick interface to the boe bot. Take a look at page 168 in the "Robotics with the Boe-bot" manual.· It gives an example of interfacing a simple switch.· If I remember correctly the joystick uses a common wire to all switches.· you will have to take that into consideration.

Second, even if the pauses were too long the servos should still operate, they would just pulse on and off.· Even though the pauses may need to be shortened, keep in mind you can also cause problems by sending the pulsout commands too often.· Also the servos will still operate correctly with a pause longer than 20, depending on your code.

Third, I don't think you need to send a command to neutral position.· when the servo no longer recieves a pulse it will coast to a stop.· Now if you want it to brake instead of coasting the neutral position command is an excellent way of doing that.· Keep in mind sudden changes in speed are hard on the servos.

agfa

science_geek

i think it is browning out, the leads to the switch and the switch i think are bigger than their supposed to be so i tried a smaller switch and it works but thanx for the help

Chris Savage

It looks to me like you need a pull-down resistor. When the switch is opened (button not pushed) the I/O pin is floating. It could be toggling between states. The pull-down resistor prevents this by holding it toward ground when the button isn’t being pressed. You will need one for each I/O pin connected to the joystick. You can find an example of this in the active-high pushbutton example schematic in the BASIC Stamp Manual or in the Editor Help file under the BUTTON command. I hope this helps. Take care.

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Chris Savage
Parallax Tech Support

science_geek

thanx for the help i got it working just a simple resistor, lol it kind of stupid me being good at electronics and all since i couldnt figure this out but hey its new to me so yeah now for my big plan