How to configure dual-wound flippers

Warning

Please ensure that you have established common ground between logic and coil power before turning on high voltage on your coils (especially on homebrew machines). Ignoring this might lock on your coils, overheat them, burn down your house or kill you. We are serious, floating grounds are dangerous. If you are not an electrical engineer read the guide about voltages and power.

In a nutshell: You need to connect your logic ground (5V/12V) and your high voltage ground (48V or 80V). A power entry or power filter board is a convenient solution to solve this (and more) issues.

Always turn all PSUs off when connecting power or you might fry all boards at once. This is generally a good idea but even more important when connecting more than one power supply to a board.

IF YOU DID NOT UNDERSTAND WHAT THIS WARNING MEANS STOP NOW AND TRY TO UNDERSTAND IT. OTHERWISE YOUR HARDWARE WILL LIKELY BURST INTO FLAMES AND YOU NEED TO WAIT A FEW DAYS FOR A REPLACEMENT OR EVEN WORSE IT MIGHT KILL YOU. IGNORING THIS IS THE MOST COMMON CAUSE FOR BROKEN DRIVER BOARDS.

This guide shows you how to configure dual-wound flippers in MPF. If you don't know what "dual-wound" flippers are, or whether you have them, take a look at the coil that your flipper uses. If it has three wires (or three tabs to connect three wires), then it's a dual-wound coil and this guide is for you.

If it has two wires (or two tabs), then read the /mechs/coils/dual_vs_single_wound guide.

Read more about "dual wound" versus "single wound" coils in the Dual-Wound versus Single-Wound coils guide.

See coil hardware for more details about the current, resistance, number of windings and the strength of coils. See dual-wound hardware for details about how to find out which terminals on your coils are hold, which are the main coil and how to connect them.

1. Add your flipper buttons

First, make sure you have entries in your machine config for your flipper buttons.

Here's an example config.yaml with two switches added:

switches:
  s_left_flipper:
    number: 1
    tags: left_flipper
  s_right_flipper:
    number: 2
    tags: right_flipper

You can pick whatever names you want for your switches. We chose s_left_flipper and s_right_flipper.

Note that we configured this switches with numbers 1 and 2, but you should use the actual switch numbers for your control system that the flipper buttons are connected to. (See How to configure "number:" settings for instructions for each type of control system.)

We also added tags called left_flipper and right_flipper. These are optional, but recommended. The reason is that MPF includes a combo switch feature which posts events when player switches are held in combination. If you add these tags to your flipper switches, an event called flipper_cancel will be posted when the player hits both flipper buttons at the same time which you can use to cancel shows and other things you want the player to be able to skip.

2. Add your flipper coils

Next you need to add entries for your flipper coils to your machine-wide config. These will be added to a section called coils:. Since we're using dual-wound coils, there will actually be two coil entries for each coil---one for the power (main) winding, and one for the hold winding.

coils:
  c_flipper_left_main:
    number: 0
  c_flipper_left_hold:
    number: 1
    allow_enable: true
  c_flipper_right_main:
    number: 2
  c_flipper_right_hold:
    number: 3
    allow_enable: true

Again, the number: entries in your config will vary depending on your actual hardware, and again, you can pick whatever names you want for your coils.

Also note that the two hold coils have allow_enable: true entries added. (In MPF config files, values of "yes" and "true" are the same.) The purpose of the allow_enable: true setting is that as a safety precaution, MPF does not allow you to enable (that is, to hold a coil in its "on" position) unless you specifically add allow_enable: true to that coil's config.

So in the case if your flippers, the hold coil of a flipper needs to have allow_enable: true since in order for it to act as a flipper, that coil needs to be allowed to be enabled (held on).

3. Add your flipper entries

At this point you have your coils and switches defined, but you can't flip yet because you don't have any flippers defined. Now you might be thinking, "Wait, but didn't I just configure the coils and switches?" Yes, you did, but now you have to tell MPF that you want to create a flipper mechanism which links together the switch and the coils to become a "flipper".

You create your flipper mechanisms by adding a flippers: section to your machine config, and then specifying the switch and coils for each flipper that you defined in Steps 1 and 2.

Here's what you would create based on the switches and coils we've defined so far:

#! switches:
#!   s_left_flipper:
#!     number: 1
#!     tags: left_flipper
#!   s_right_flipper:
#!     number: 2
#!     tags: right_flipper
#! coils:
#!   c_flipper_left_main:
#!     number: 0
#!   c_flipper_left_hold:
#!     number: 1
#!     allow_enable: true
#!   c_flipper_right_main:
#!     number: 2
#!   c_flipper_right_hold:
#!     number: 3
#!     allow_enable: true
flippers:
  left_flipper:
    main_coil: c_flipper_left_main
    hold_coil: c_flipper_left_hold
    activation_switch: s_left_flipper
  right_flipper:
    main_coil: c_flipper_right_main
    hold_coil: c_flipper_right_hold
    activation_switch: s_right_flipper

4. Enabling your flippers

By default, MPF only enables flippers when a game is in progress. So if this is a first-time config and you haven't configured your ball devices and start button and everything, you can't actually start a game yet, which means you can't test your flippers.

Fortunately we can get around that by configuring your flippers to just automatically enable themselves when MPF starts. To do this, add the following entry to each of your flippers in your config file:

enable_events: machine_reset_phase_3

So now the flippers: section of your config file should look like this:

#! switches:
#!   s_left_flipper:
#!     number: 1
#!     tags: left_flipper
#!   s_right_flipper:
#!     number: 2
#!     tags: right_flipper
#! coils:
#!   c_flipper_left_main:
#!     number: 0
#!   c_flipper_left_hold:
#!     number: 1
#!     allow_enable: true
#!   c_flipper_right_main:
#!     number: 2
#!   c_flipper_right_hold:
#!     number: 3
#!     allow_enable: true
flippers:
  left_flipper:
    main_coil: c_flipper_left_main
    hold_coil: c_flipper_left_hold
    activation_switch: s_left_flipper
    enable_events: machine_reset_phase_3
  right_flipper:
    main_coil: c_flipper_right_main
    hold_coil: c_flipper_right_hold
    activation_switch: s_right_flipper
    enable_events: machine_reset_phase_3

5. Configure your control system hardware

At this point your flipper configuration is technically complete, though there are two other important things you may have to do first:

If you're using physical hardware, you may need an additional section in your machine config for your control system. (For example, FAST Pinball and Open Pinball Project controllers require a one-time port configuration, etc.) See the control system documentation for details.

6. Adjust your flipper power

As a safety precaution, MPF uses very low (10ms) default pulse times for coils. In most cases, 10ms will not be enough power to physically move the flippers when you hit the button. (You might hear them click or buzz without actually seeing them move.)

So check out the documentation in the coils section for instructions on how to adjust the pulse power and the hold power for the coils you're using for your flippers.

Related How To guides

• Dual-wound Coils
• Dual-Wound versus Single-Wound coils

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