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    Servo Wiring

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    • Red Sand Robot
      Red Sand Robot last edited by

      So, from reading the documentation I understand that with my v1.03 board I will need to wire a 220μf capacitor between the +5 and GND of the servo.

      Would that mean the capacitor would be wired in series with the GND wire before it connects to the board, since there would be still be +5 on one side of the capacitor?
      i.e. -----GND Wire------><220μf><---------<GND Pin, Duet

      almost an engineer

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      • A Former User
        A Former User last edited by

        You're probably looking for an electrolytic capacitor, those are polarized. Connect the negative leg (which is marked on the case) to GND and other leg to 5v.

        You can put the capacitor on the motor, on the connector or on the board.

        PhoenixSimon 1 Reply Last reply Reply Quote 0
        • Red Sand Robot
          Red Sand Robot last edited by

          0_1558719210076_60745599_324185308259616_8467248864074661888_n.jpg

          @bearer Would wiring it like this work? Sorry, I'm very visual when it comes to thinking about wiring and circuits, just wanting to double check.

          almost an engineer

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          • A Former User
            A Former User last edited by

            Now its in series with ground. Scrap the ground symbol and move that side to 5v. So that is is in parallel with the servo.

            And observe the markings on the capacitor when connecting it.

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            • Red Sand Robot
              Red Sand Robot last edited by

              0_1558719948794_61119332_940427036306821_3017787255033954304_n.jpg

              @bearer So like this, correct? The capacitor would be wired in parallel between the +5 and GND of the servo.

              almost an engineer

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              • A Former User
                A Former User last edited by

                That looks better 👍

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                • Red Sand Robot
                  Red Sand Robot last edited by

                  Awesome, thank you!

                  almost an engineer

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                  • dc42
                    dc42 administrators last edited by

                    Whether you need the capacitor at all depends on the size of the servo. What servo is it?

                    Duet WiFi hardware designer and firmware engineer
                    Please do not ask me for Duet support via PM or email, use the forum
                    http://www.escher3d.com, https://miscsolutions.wordpress.com

                    Red Sand Robot 1 Reply Last reply Reply Quote 0
                    • Red Sand Robot
                      Red Sand Robot @dc42 last edited by

                      @dc42 Something like either of these, can't remember the exact listing off of Amazon I got them from.

                      https://www.adafruit.com/product/169?gclid=Cj0KCQjwrJ7nBRD5ARIsAATMxstzXQM3ltsIyAbbzZGCbQgzmdHpIgmKx94lhGbRou-AgeJf_Sjn49EaAveCEALw_wcB

                      https://www.amazon.com/FPVKing-Helicopter-Airplane-Remote-Controller/dp/B07N2B99B6/ref=asc_df_B07N2B99B6/?tag=hyprod-20&linkCode=df0&hvadid=343191214486&hvpos=1o5&hvnetw=g&hvrand=14170196726056022913&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033692&hvtargid=pla-744356057742&psc=1&tag=&ref=&adgrpid=64450094290&hvpone=&hvptwo=&hvadid=343191214486&hvpos=1o5&hvnetw=g&hvrand=14170196726056022913&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033692&hvtargid=pla-744356057742

                      almost an engineer

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                      • Red Sand Robot
                        Red Sand Robot last edited by

                        @dc42 It is a micro servo, 9g weight, 1.5-1.7kg/cm (4.8V-6V) stall torque. Commonly referred to as a 9G servo.

                        almost an engineer

                        dc42 1 Reply Last reply Reply Quote 0
                        • Red Sand Robot
                          Red Sand Robot last edited by

                          @dc42 So if I took two 100μF and two 10μF capacitors and soldered them together in parallel, and then connected that in parallel with the +5V and GND wires for the servo that should work correct? From what I understand, to find the equivalent capacitance when connecting connecting capacitors in parallel you sum of all the individual capacitances.

                          almost an engineer

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                          • A Former User
                            A Former User last edited by A Former User

                            Tollerances are usually quite loose on capacitors so I wouldn't bother with the 10uF caps. Given the small size of the servo I'd probably just add a single 100uF cap and if the board is stable and doesn't reset when the servo is under load call it done, and add the 2nd cap if its unstable.

                            edit: but, yes, your theory for equivalent capacitance is theoretically correct

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                            • dc42
                              dc42 administrators @Red Sand Robot last edited by dc42

                              @red-sand-robot said in Servo Wiring:

                              @dc42 It is a micro servo, 9g weight, 1.5-1.7kg/cm (4.8V-6V) stall torque. Commonly referred to as a 9G servo.

                              I haven't conducted any tests with a micro servo. It's quite likely that it doesn't need any extra capacitance at all; but if it does, 100uF should be more than adequate.

                              The recommendation of 220uF was based on tests I did using a MG996R servo, weight about 58g. I have some 12.5g servos now (HS-70MG) so I'll test a pre-1.04 board with one of those too.

                              Duet WiFi hardware designer and firmware engineer
                              Please do not ask me for Duet support via PM or email, use the forum
                              http://www.escher3d.com, https://miscsolutions.wordpress.com

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                              • PhoenixSimon
                                PhoenixSimon @Guest last edited by

                                @bearer
                                Hi
                                I have seen you have mentioned you can put the capacitor on the motor, on the connector and on the board.
                                What is the proper and safest way to do this?
                                I have connected the capacitor to the connector just to try the servo but it doesn't look very professional and safe.
                                How could I connect the capacitor to the board?
                                What else would you suggest?

                                thanks

                                A Former User 1 Reply Last reply Reply Quote 0
                                • A Former User
                                  A Former User @PhoenixSimon last edited by

                                  @PhoenixSimon In decreasing order of likelyness:

                                  • simply crimp both the servo wire and the capacitor leads into the terminal and maybe add some sleeving on the exposed part of the leads
                                  • solder capacitor to the bottom of the board, onto the solder joints of the servo header.
                                  • remove the plastic "shroud" for the servo header then wire wrap + solder the capacitor leads onto the bottom of the header pins
                                  • solder capacitor to pcb inside servo, 3d print new cover.
                                  PhoenixSimon 1 Reply Last reply Reply Quote 0
                                  • PhoenixSimon
                                    PhoenixSimon @Guest last edited by

                                    @bearer
                                    thank you very much. I highly appreciate your help.

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