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How to configure coils/drivers/magnets (FAST Pinball)

Related Config File Sections:

To configure coils, drivers, motors, and/or magnets (basically anything connected to an IO board's driver outputs) with FAST Pinball hardware, you can follow the guides and instructions in the Coils (Solenoids) docs.

High voltage can be dangerous.

It's important that you wire your boards correctly. FAST Pinball has detailed wiring guides which you should follow. Please see the wiring guide for the FAST Nano Controller on their website.

Once everything is wired, here's how you configure MPF to use a FAST Nano Controller.


When you're using FAST IO boards, drivers plug into individual IO boards. Then the IO boards are connected together in a loop.


The number: setting for each driver is its board's position number in the chain, then the dash, then the driver output number. Note that the position number starts with zero, so the first IO board in the chain is 0, the second is 1, etc.

    number: 0-0    # first board, driver 0
    number: 2-14    # third board, driver 14


  • The first board in the chain is board 0.
  • The boards are counted in the direction of the "out" connector on the controller board.
  • Different models of IO boards have different numbers of drivers, and MPF will make sure that the numbers work for each type of board. (e.g. a driver number 10 isn't valid on an 0804 board since that board only has 4 drivers numbered 0-3).

Also note that prior versions of MPF just numbered all the drivers in one continuous sequence from the first board through the last, but that was confusing. You can still do that if you want (in integer format), but we feel the board-input format is much easier to understand.

Pulse Power

In the Coils (Solenoids) section of the documentation, we talked about how adjusting a coil's pulse time can affect its strength. Adjusting the coil's pulse times still assumes that 100% power will be applied to that coil during that pulse time.

However, FAST Pinball controllers allow you to specify the power that's applied to the coil during the initial pulse time. This is similar to the Adjust coil hold power, except it applies to the initial pulse time instead of the extended hold time.

You can configure the pulse power by adding a default_pulse_power: setting to a coil definition and then specifying the power value from 0-1. (Like default_hold power, 0% to 100%)

For example, consider the following configuration:

    number: 1-3
    default_pulse_ms: 30
    default_pulse_power: 0.5

When MPF sends this coil a pulse command, the coil will be fired for 30ms at 50% power. You can even combine default_pulse_power and default_hold_power, like this:

    number: 1-3
    default_pulse_ms: 30
    default_pulse_power: 0.5
    default_hold_power: 0.25

In this case, if MPF enables this coil, the coil will be fired at 50% power for 30ms, then drop down to 25% power for the remainder of the time that it's on.

Setting Recycle Times

FAST Pinball controllers allow you to precisely control the recycle time for coils or drivers.

A coil's recycle: setting is a boolean (True/False), which is set to False by default. When using FAST Pinball hardware, if you set recycle: true, then the recycle time is automatically set to twice the coil's default_pulse_ms: setting. (e.g. a coil with a default_pulse_ms: 30 and recycle: true will have a 60ms recycle time).

However, with FAST Pinball hardware, you can manually set a coil's recycle time by adding a recycle_ms: setting, like this:

    number: 1-4
    default_pulse_ms: 30
      recycle_ms: 100

If you manually specify a recycle_ms value, then that's the value that's used and the coil's recycle: (true/false) setting is ignored.

Replacing FETs on FAST Driver Boards

In case you burned one of your FETs on a FAST board those can be replaced. Usually, FETs will turn on permanently when burned. As a result your coils will be stuck on and your fuse should burn (if not your coil will). If you output does not activate at all a burned FET is rather unlikely the culprit.

Consult the FAST support for an official repair. Alternatively, you can buy IRL540NSTRLPBF FETs from your electronics supplier and replace them yourself. Replacing SMD FETs is possible with a decent soldering iron and some practice.

What if it did not work?

Have a look at our FAST troubleshooting guide.

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