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$3 Servo Tester — Parallax Forums

$3 Servo Tester

ercoerco Posts: 20,256
edited 2013-03-02 20:06 in General Discussion
Lots of servo chatter here lately. A useful $3 tool is this handy-dandy 3-mode servo tester. Works like this $15 unit:
http://www.youtube.com/watch?v=KSmRWhTQx6w&feature=related

Mode 1: manual control via pot
Mode 2: center (1500 ms output)
Mode 3: oscillate (1000-2000 ms output)

But it's just $3 on Ebay China http://cgi.ebay.com/ESC-Servo-tester-3-Channels-CCPM-Meter-Checker-4-8-6V-/150618800040?pt=Radio_Control_Parts_Accessories&hash=item2311947fa8

or $4.48 from Hobby King: http://www.hobbyking.com/hobbycity/store/__14774__HobbyKing_Servo_Tester.html

Hack four of those and you can build this robot arm on the cheap! http://www.youtube.com/watch?v=-XChu20hTxU
servotester.jpg
400 x 400 - 51K

Comments

  • stevebzzzzzstevebzzzzz Posts: 38
    edited 2011-07-19 09:37
    Nice:

    I am so excited to be coming to the end of the SERVO chapter. Here is my first servo circuit

    Cheers....
  • ercoerco Posts: 20,256
    edited 2011-07-19 09:39
    Well done. Not too bad for the BS2 you were chuckling at only a couple days ago, eh stevebzzzzz? :)
  • iDaveiDave Posts: 252
    edited 2011-07-19 16:12
    Good one erco. I could use one of these and for under $3 I'll bite!
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2011-07-19 16:14
    erco wrote: »
    Lots of servo chatter here lately. A useful $3 tool is this handy-dandy 3-mode servo tester. Works like this $15 unit:
    http://www.youtube.com/watch?v=KSmRWhTQx6w&feature=related

    Mode 1: manual control via pot
    Mode 2: center (1500 ms output)
    Mode 3: oscillate (1000-2000 ms output)

    But it's just $3 on Ebay China http://cgi.ebay.com/ESC-Servo-tester-3-Channels-CCPM-Meter-Checker-4-8-6V-/150618800040?pt=Radio_Control_Parts_Accessories&hash=item2311947fa8

    or $4.48 from Hobby King: http://www.hobbyking.com/hobbycity/store/__14774__HobbyKing_Servo_Tester.html

    Hack four of those and you can build this robot arm on the cheap! http://www.youtube.com/watch?v=-XChu20hTxU

    I already had a Servo tester but a friend of mine at work is now $3 poorer....
  • ercoerco Posts: 20,256
    edited 2011-07-19 16:18
    Since there are 3 sets of servo pins, you can also use it as a synchronizer or "consistency tester" like this guy...

    http://www.youtube.com/watch?v=UOr4NNKZErM&NR=1 :)
  • localrogerlocalroger Posts: 3,451
    edited 2011-07-20 05:49
    Just ordered one. This will come in handy for debugging the hardware part of a big project I just started.
  • ercoerco Posts: 20,256
    edited 2011-08-16 11:53
    FYI, these servo testers DO NOT have reverse polarity protection on the battery connector.

    I have learned to love the fleeting smell of magic smoke! :)

    My 7.4V lipo made short work of that poor servo tester. Fortunately I bought several!

    6V of AA alkalines might be more forgiving, but that lipo battery had the right battery connector and everything.
  • PliersPliers Posts: 280
    edited 2011-08-16 14:39
    My only experience with this type of servo is from a Boe bot kit.
    I would think, to test a servo, I would like to know it's accuracy, repeatability, speed and strength.
    Not just to see it move.
  • ercoerco Posts: 20,256
    edited 2011-08-16 14:48
    When you have dozens of servos of various speeds, torque, various sizes, some regular, some continuous rotation, some installed on a robot, some on an arm, some in a drawer, some in the process of being modified for CR, some hacked in various ways, some with stripped gears, some work, some don't, these testers are worth their weight in gold. Certainly $3.

    PLUS, they are very entertaining to my two-year old twin girls: they twist a knob and make something move. These testers buy me a few moments of peace!
  • ercoerco Posts: 20,256
    edited 2011-08-21 00:15
    erco wrote: »
    FYI, these servo testers DO NOT have reverse polarity protection on the battery connector.

    Correction: turns out I damaged the servo; the servo tester is fine after reverse voltage was accidentally applied. Still not recommended.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-01-12 07:32
    erco,

    Ever since I saw this post months ago, I've wanted to make my own servo tester.

    My servo tester doesn't have the knob for adjusting the servo position (which I admit would be nice) but it uses the QuickStart's touchpads to position the servo.

    I beleive my version has a few features the $3 version doesn't.

    The oscillation period can be adjusted. You can use this feature to see how fast your servos can move.

    The end points can both be independently adjusted. The end points affect both the oscillating servos (the travel amount changes as the end points change) and the "static" servo. The static servo's position can be adjusted up to the end points but not past.

    The various parameters are displayed on a terminal window. The program doesn't require the QuickStart is connected with a PC because the parameters are also displayed on the LEDs. The parameters are displayed as binary infomation on the LEDs. When all the LEDs are off the static servos are centered (this is also the starting position). The LEDs indicate how far from centered the servos are (in units of 2us). It's a lot easier to read the parameters from the terminal window.

    It wouldn't be hard to change the program to output to a LCD, TV or some other display.

    I think the main advantage of the QuickStart servo tester over the $3 servo tester is the ability to change the end points. My cheap little HobbyKing servos only move through half their range with pulses ranging from the standard 1000us to 2000us.

    If you already have a QuickStart then this servo tester is free. Otherwise for $25 you can buy a servo tester that's smart enough to control a robot.
  • ercoerco Posts: 20,256
    edited 2012-01-12 08:38
    XLNT. Yep, variable endpoints are def better, and you can make a servo tester out of anything you can program. A Prop, Stamp, PicAxe, Ardy, Handy Board, etc. Of course, the fact that those are reprogrammable guarantees that they won't remain a servo tester for long. They'll soon be repurposed to prove they can replace a $2 Turnigy servo reverser: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=17033

    IMHO, these testers are so handy and cheap that everybody oughtta have one on their bench and ready to go. Duane, PM me your address and I'll mail you one free for all the wonderful things you do here in the Forum!
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-01-12 12:01
    erco wrote: »
    you can make a servo tester out of anything you can program

    Yes, but part of this exercise, besides showing myself I have the will power to resist at least one of the great bargains you post, was to show off the QuickStart board. I'm afraid you're right about it getting repurposed to something else (though it wont be a servo reverser:smile:).

    I'll take you up on your free servo tester. Thanks.

    Do you have a QuickStart board? If not, I'll send you one of mine. I usually keep a couple within arms reach. They're so easy to use to test out new devices (like the $4 ultrasound sensors you pointed out that I couldn't resist). It's really handy to have the board powered by the same USB line used to program it.
  • ercoerco Posts: 20,256
    edited 2013-03-02 20:06
    Two bucks now, not three per the thread title. So sue me!

    Well, $2.18, but free ship. Christmas comes early (or very late).

    http://www.ebay.com/itm/Brand-New-Blue-CCPM-Servo-Consistency-Master-Servo-tester-S812-/261174258117?pt=US_Radio_Control_Control_Line&hash=item3ccf32e9c5
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