Help with servo

By Pasquale
2008-07-01 12:14

hi, first of all: sorry, my english is so bad. and I mean .. BAD.

I am a beginner, and I have some problems with servo controller! I fallowed "how to make your first robot" by fritsl (great fritsl..!!), except I used a srf05 not a ir sharp sensor device. (there's an other problem, I connected srf05 like http://letsmakerobots.com/node/66 but I can't insert a functionally command string in the fritsl's program that let it work, although it seems to work with the node 66's code)

I connected the servo using a standard servo connection (soldering an extra pin to output 0)

When I upload "servo 0, xxx" the servo does nothing. When I disconnect it from the picaxe 28x1 and than connect it again it takes a little turn. When I upload the program of the fristl guide the gear motors go on, but the servo turns on its right, than takes a pause.. than turns on its right again, and so on.. and so on.

I supposed that the problem is that I don't bought PICAXE servo upgrade pack and I haven't the "yellow chip", SO I LEFT THE DARLINGTON-DRIVER IN .. .. but I can't figurate out what the "yellow chip" is and I can't say its name to the electronic's shop! .. .. I don't understand what is the function of this yellow chip too..

could you help please? thanks all..

By jka @ Tue, 2008-07-01 12:20

go to the "start here" link

go to the "start here" link at the top. In the text you find:

---quote---

This yellow chip is actually just 8 * 330 Ohm's resistors in a neat package. And so, if you should have a resistor, you can just insert it instead in slot numbered “0”, as this is the only one we will use, when we only use one servo.

---end quote---

So: rip out the darlington, insert a single 330 ohm resistor or buy a block of 330ohm resistors and use that. It doesn't have to be yellow...

By Pasquale @ Tue, 2008-07-01 17:05

oh... thanx. block of 330ohm

oh... thanx. block of 330ohm resistors. I must read more slow. now I have to set only the srf05, for now doesn't work.

By CaptainTuna @ Tue, 2008-07-08 07:32

i can't get it to work even

i can't get it to work even with my resistor on (same thing happens: it turns a bit when i first connect it but then does nothing).

i've tried to test my resistor with the multimeter (in continuity mode) and i saw it displays "0" whereas with my 220ohm resistor it displayed 218 or similar values.

i guess my resistor's gone. oh by the way i once got the servo connected without anything...does that harm the servo?

By Vansu @ Tue, 2008-07-08 12:59

I think I have the same

I think I have the same problem. I bought a pack of resistor from The Source and it said on the package that its 20 in total and it said that there are five of each different resistor in there. (5)230, 330, 440 etc. but when I ask the guy at the store he said that each resistor can work for all of the resistor listed. but I guess he's wrong? maybe this is my problem with the servo. I read the manual and could not figure out whats wrong with it. I hot everthing working. it can run and the sensor works great. just need the servo to work.

By beta-j @ Wed, 2008-07-09 14:50

guys, the 330ohm resistor

guys,

the 330ohm resistor should have orange-orange-brown stripes on it follwoed by a gold stripe. any other markings means that the resistor is not 330ohms!

Also make sure that you ALWAYS check the resitance of the resistor when it is DISCONNECTED from the board. DO NOT CHECK RESITANCES WHILE IT IS CONNECTED!

Also, if you want to check resistance values do not usethe continuity setting on the multimeter...it has a resistance setting for a reason!.

If you want to test whether the servo is working use the following code:

main:

servo 0, 75

servo 0,200

goto main

the servo should go one way and then the other and repeat indefinitely...

By CaptainTuna @ Wed, 2008-07-09 15:21

point is that the stripes on

point is that the stripes on my resistor are unreadable else i'd have already done that...and i just used the continuity setting because it seemed to work correctly with my other resistor...anyways i'll have to buy a better resistor! (with readable stripes this time!! :D i erroneously didn't check em when i bought it)

By beta-j @ Wed, 2008-07-09 16:09

what do you mean by 'the

what do you mean by 'the stripes are unreadable'? are they worn off? can you post a pic?

have you tried measuring the impedance using the resistance setting on the multimeter?

By Vansu @ Thu, 2008-07-10 02:55

resistor

my servo is moving both left and right but it move like left 3 second and right 3 seconds. My resistor is red,red, brown and gold I guess I got the wrong resistor.

By jklug80 @ Thu, 2008-07-10 03:01

thats a 220ohm you usually

thats a 220ohm you usually use a 330ohm resistor

By Vansu @ Thu, 2008-07-10 04:29

oh no wonder!

no wonder I my servo go wacko because the resistor is not right. Thanks!

By TheCowGod @ Thu, 2008-07-10 04:59

Is this resistor connected

Is this resistor connected on the servo's signal line? The white/yellow wire? I don't have any experience with a picaxe, but I've never used any resistors when connecting servos to the Arduino or Basic Stamp, and it works just fine with no resistor at all. Is there something different about the Picaxe that requires a resistor? Anyway, since it's a digital signal (0v and 5v, no in-betweens), I'd be surprised if a slightly different resistor value kept it from working. But again, I've never used a Picaxe, so maybe I should keep my mouth shut :)

Dan

By Vansu @ Thu, 2008-07-10 12:45

me too

I have no idea about it either. I just try to follow with Fritsl instruction and I been playing around with the servo code and I try everything but its not working right so I think the resistor is my problem.

By Vansu @ Thu, 2008-07-10 03:12

I found the pic for 330 resistor

By CaptainTuna @ Thu, 2008-07-10 10:32

here it is...unfortunately i

here it is...unfortunately i forgot to check it before buying it..

By beta-j @ Thu, 2008-07-10 10:56

OMG! that's the weirdest

OMG! that's the weirdest looking resistor i've ever seen! :O

By CaptainTuna @ Thu, 2008-07-10 11:42

same goes for me...anyways

same goes for me...anyways it doesn't work .. 0 reading on the multimeter. tomorrow i am gonna get a new one (i'll check it with the multimeter before buying it this time!) thanks for the help.

By CaptainTuna @ Fri, 2008-07-11 10:17

hooray! new resistor and

hooray! new resistor and servo working as it should! :D

By Vansu @ Fri, 2008-07-11 12:27

good for you

Mine is still not working correctly even though I have the right resistor. The servo still spinning wildly. Is it maybe I got the wrong servo. Mine servo indicate that it is a continous sero. Does that make a different?

By CaptainTuna @ Fri, 2008-07-11 13:11

i guess it does!!! try F5ing

i guess it does!

check this out http://letsmakerobots.com/node/1313

you can stop it by writing servo 0, 150

By Pasquale @ Wed, 2008-07-23 17:46

again with servos xD

Hi all..! I've tried to install the picaxe 28x1 on a remote controlled car. I've just set the motor of the back wheels and they work.but there's a problem with the servo that controls the frontwheels (and makes them turn)..

this servo has only TWO wires (not 3 like others) .. I've tried to connect it to ground and pin, and it take some voltage (it turn on the left, permanently).. but it doesn't respond to commands.. I've tried with a resistor... then a transistor.. but it doesn't work.. help please T_T thanks

By GobliZ @ Wed, 2008-07-23 18:16

Are you sure it is a servo,

Are you sure it is a servo, and not a solenoid like in here?

By Pasquale @ Wed, 2008-07-23 19:29

100% sure, it's a servo.. I

100% sure, it's a servo.. I will post a photo soon

edit: 50 % sure.. -_- ..

By Pasquale @ Wed, 2008-07-23 19:02

there are two wires, yellow

there are two wires, yellow and green...

when the G is on the ground, and the Y is on the pin, it turns on right

when the Y is on the ground, and the G is on the pin, it turns on left ... and the picaxe28 has no program on..

so how can I set and control this thing..? O_o

By jklug80 @ Wed, 2008-07-23 19:24

Sounds like a solenoid to

Sounds like a solenoid to me... High on green pin and low on yellow or vise versa to make it steer. Low on both I assume is center.

By TheCowGod @ Wed, 2008-07-23 19:53

Actually it sounds like just

Actually it sounds like just a regular motor, i.e. a servo with no control electronics. Is the steering "all or nothing"? Or can you just touch the wires to the battery quickly and have it turn just a little bit? If it's "all or nothing" then it's a solenoid, and you should use a relay to control it the way Frits did in his Wallracers. If it can be turned just a little bit, then it's just a regular DC motor, and you'll need an H-bridge (or motor driver chip like the L293D or SN754410) to control it.

Dan

By Pasquale @ Wed, 2008-07-23 20:03