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Team Pasty Build Diary: Loki

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  • Team Pasty Build Diary: Loki

    Hi Guys, pretty new here so this is my first post. I've started building a featherweight which I am naming Loki (hopefully it's not taken!). It's going to have electric lifting forks, inspired by Panic Attack and Biohazard. At the moment I have an MDF mock up of the chassis and the following components:

    2x drill motors
    2x BotBitz 85A ESCs
    1x Orange 6CH RX
    1x Spektrum DX5E TX
    2x 75mm RobotChallenege Blue Wheels
    2x 7.2V 3300 mAh NiMH batteries in parrallel (borrowed from my Battle Rat, Nasty Pasty)

    The final chassis will be made from HDPE and hopefully if I can get enough cheap off cuts the armour will be titanium. I have a few new bits and bobs coming next week, a Turingy V-Tail Mixer (controlling is interesting at the moment!) and 2x 9.6V 3300 mAh NiMH batteries and an electric actuator.

    Would appreciate feedback/tips/advice

    Here's some photos of progress so far:
    [attachment=1:kf34ow3k]2013-02-22 22.06.41.jpg[/attachment:kf34ow3k]
    [attachment=0:kf34ow3k]2013-03-03 15.29.39.jpg[/attachment:kf34ow3k]
    And a video:
    https://www.youtube.com/watch?v=FdrcsAzbNHA
    Attached Files

  • #2
    Re: Team Pasty Build Diary: Loki

    Cool design, what controllers are they?

    Comment


    • #3
      Re: Team Pasty Build Diary: Loki

      ^They're the 85a Botbitz speed controller. It's a reprogrammed and electronically tweaked brushless motor controller. Here's their site: http://www.botbitz.com/

      As I have said, your machine is looking very nice thus far, Chris! You're going to be amazed when you up your batteries to the 9.6v in series, the machine will be over twice as fast as it is now.

      Comment


      • #4
        Re: Team Pasty Build Diary: Loki

        Will it be a four-bar lifter like Biohazard or fork lifter like Panic Attack?
        Doesn't the Spektrum DX5E have built-in mixing?
        How will you control the lifter? Another BotBitz 85A ESC or using an H-Bridge?

        I know it's just a mock-up buy, when you get the actuator, make the robot as compact as possible, you will save lots of weight and money in materials.

        Looking good.

        Comment


        • #5
          Re: Team Pasty Build Diary: Loki

          http://www.spektrumrc.com/ProdInfo/File ... Manual.pdf

          Go to page 11 on the PDF. Look at ELEVON/DELTA mixing. This will allow you to mix the signals at the transmitter without the need for a separate one in the robot.

          You may have to swap cables going into your receiver around or reverse a channel but it will work with the right combination!

          Comment


          • #6
            Re: Team Pasty Build Diary: Loki

            Originally posted by Merkabah_PT
            Will it be a four-bar lifter like Biohazard or fork lifter like Panic Attack?
            Doesn't the Spektrum DX5E have built-in mixing?
            How will you control the lifter? Another BotBitz 85A ESC or using an H-Bridge?

            I know it's just a mock-up buy, when you get the actuator, make the robot as compact as possible, you will save lots of weight and money in materials.

            Looking good.
            It will be a four bar lifter with forks, at least that's what I'm aiming for.

            I tried to find out about the mixing, from what I've read it doesn't but I could be wrong. I'm all new to this lol

            Yeah I've made an H-bridge to control the lifter, tried to upload a picture but it only let me do 2 for some reason?


            And thanks I'll keep compactness in mind

            Originally posted by Ellis
            You're going to be amazed when you up your batteries to the 9.6v in series, the machine will be over twice as fast as it is now.
            Looking forward to it

            Comment


            • #7
              Re: Team Pasty Build Diary: Loki

              Eventorizon posted the manual for you TX, take a look at it.

              It took me about 1hour to be able to connect my TX to the computer and make the mixing work. Trial and error.
              My TX alows me to connect it to the computer while i operate the robot, so i could test every change as i made them.

              Comment


              • #8
                Re: Team Pasty Build Diary: Loki

                [quote=Eventorizon]http://www.spektrumrc.com/ProdInfo/F...r /> <br /> Go

                Comment


                • #9
                  Re: Team Pasty Build Diary: Loki

                  Reversing the channel should do exacly the same thing as reversing the motor wires, but if ch.rev. isn't working you can do that.
                  I don't know how to mixing is done on your TX, but in mine i have to assign 3 pairs of master/slave channels and say their percentages, like:

                  Master: ch1 %:100
                  Slave: ch2 %:-100

                  I had to mess around with rev. and +/-% to get it right.

                  Try to reverse the motor wires, if that does the trick, you are all done.

                  Comment


                  • #10
                    Re: Team Pasty Build Diary: Loki

                    Looks very nice for a wood bot.
                    Forget the ti stick with MDF

                    Comment


                    • #11
                      Re: Team Pasty Build Diary: Loki

                      Originally posted by Merkabah_PT
                      Reversing the channel should do exacly the same thing as reversing the motor wires, but if ch.rev. isn't working you can do that.
                      I don't know how to mixing is done on your TX, but in mine i have to assign 3 pairs of master/slave channels and say their percentages, like:

                      Master: ch1 %:100
                      Slave: ch2 %:-100

                      I had to mess around with rev. and +/-% to get it right.
                      I don't think the DX5E can do that Mine just has switches for mix on/off and then you can reverse the channels

                      Comment


                      • #12
                        Re: Team Pasty Build Diary: Loki

                        Maybe you can find some info on these links:

                        http://www.rcpowers.com/community/th...bilities.9387/
                        http://www.youtube.com/watch?v=rmdst80KZd4
                        http://www.rcgroups.com/forums/showthread.php?t=943411
                        http://www.rcgroups.com/forums/showthread.php?t=1273639


                        From what i read on the third link, there is a known problem while using the mixing and reversing, when you reverse on channel, the TX automatically reverses both.

                        Hope you can find a solution.

                        Comment


                        • #13
                          Re: Team Pasty Build Diary: Loki

                          If I remember rightly (and I may not since I don't own a DX5e), the built-in mixing on the DX5e limits the elevator channel to around 60% so your robot will seem unusually slow when going forward and back, but will turn left and right at the correct speed. It's not something that's adjustable as far as I'm aware so your best bet would be to leave it turned off and use an external mixer if you want single stick driving. Although watch what external mixer you buy as some of them also have fwd/bck limits.

                          Comment


                          • #14
                            Re: Team Pasty Build Diary: Loki

                            The DX5E has half throws on all mixed channels I find. Get a GWS mixer, they don't limit and don't mess up your failsafing like the other cheap ones.

                            Sometimes you do just need to switch the wires on the motor, swapping functions on the Tx will only get you so far and the DX5E is pretty limited.

                            Comment


                            • #15
                              Re: Team Pasty Build Diary: Loki

                              Thanks for all the info regarding mixing on the DX5E. It would appear that this model has a fault so can't use the in built mixing, bummer.

                              Received the new batteries today so got them all in nicely and now the robot really goes!

                              Also inserted a removable link, made the front of the chassis angled and gave it some aluminium armour.
                              [attachment=1:3oj6tw6o]2013-03-06 15.14.31.jpg[/attachment:3oj6tw6o]
                              [attachment=0:3oj6tw6o]2013-03-06 15.15.16.jpg[/attachment:3oj6tw6o]


                              Am having some problems though. When on it will intermittently move on it's own, and it seems like sometimes the wheels keep going for a tiny bit after letting go of the stick.

                              Could the problem be down to the cheap mixer? I checked the failsafing after what PJ-27 said and it has messed it up.

                              I took it outside for a test run and managed to drive it into the curb and bend a corner of the aluminium so one of the wheels was off the ground

                              Could someone tell me where I would wire in a power LED?


                              Cheers guys
                              Attached Files

                              Comment

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