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Power Functions Speed Regulation

7BS7BS CaliforniaMember Posts: 60
edited August 2017 in Building and Techniques

I couldn't find a thread about this—

I'm wondering about the effects of the speed regulation dial on #8878 Rechargeable Battery Box.

How will the power output to a motor be effected if I use #8879 IR Speed Remote Control to activate the motor--will the speed dictated by the remote control override the speed setting on the battery box?

In this setup, it possible to change the direction, but not the speed, using the remote?

To clarify, I'm creating a convoluted device in which an EV3 moves the dials and stop buttons on a power functions remote to control a power functions train. (No, I don't want to put the EV3 on the train.) My problem so far is that the remote sometimes activates twice or not at all when it should activate once when the dial is rotated 22.5 degrees, causing the train to go at an unpredictable speed. So, I'm wondering if the rechargeable battery box, which I don't own, can stop the train from going faster than the first power level.

Thank you for your help.


  • PaperballparkPaperballpark Near ManchesterMember Posts: 4,228
    If I remember correctly, the IR controller will override whatever speed setting the dial is at on the rechargable battery box.

    The IR controller is... basic. IR is notorious anyway for a range of issues. Speaking as someone who has run multiple IR trains at probably a dozen shows - all with rechargable battery boxes - by far the easiest thing to do is use the IR to take trains up to a certain speed (full speed is easiest), and then just leave them at that speed until the battery eventually dies 3-4 hours later.
  • 7BS7BS CaliforniaMember Posts: 60
    Thanks, looks like I'll have to make do with what I have somehow.
    I can't just run it because I want the train to go back and forth along a linear path and make stops along the way, without my having to control it manually.
  • PaperballparkPaperballpark Near ManchesterMember Posts: 4,228
    Someone from Brickish LUG has done that, with IR transmitters above the tracks, but I don't know what else he used or how he did it. I don't think he's on Brickset.
  • MattDawsonMattDawson Solihull, UKMember Posts: 1,386
    @Paperballpark he's probably set the PF to power 9V track. :P
  • CCCCCC UKMember Posts: 20,366
    You can do that quite easily with Arduino. You just need a distance sensor at each end of the track and a IR led (or more than one for a large setup) that sends the signal to the train. Someone has already written the library of routines /signals for the PF IR transmitter, so very little knowledge is needed.
  • sid3windrsid3windr BelgiumMember Posts: 1,460
    As I understand it:

    The PF cables have 4 wires, 2 give 9V power, 2 give "speed-regulated power". When you turn the dial on the battery box, the latter 's voltage is changed.

    However, the IR receiver just takes 9V from the former 2 wires, and ignores the speed setting. It then on its own modifies the speed-regulated wires on its own outputs.

    So indeed, the IR receiver overrides the speed set on the battery box.
  • 7BS7BS CaliforniaMember Posts: 60
    That's too bad, but thank you for the explanation. I might have to put the EV3 on the train after all.
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