Table of contents
  1. Setting up a custom json file to describe your daisy pin setup
    1. How is your hardware setup?
    2. Custom json for a custom Daisy setup
    3. Pin numbers
    4. Types of components and the way they communicate
    5. Aliases
    6. Download / link / full example
      1. pd2dsy
      2. json2daisy
      3. Simple.json (Synthux)
      4. Synthux Simple Touch - jonwtr - setting up MPR121 Touch Sensor
        1. Edit a part of the toolchain json components definition file

Setting up a custom json file to describe your daisy pin setup

How is your hardware setup?

It’s not easy to provide a general custom json, as that’s mostly not going to be the same setup as your unique build.

When making your own device the way you connect various components to the Daisy pins will almost certainly be different from another project. Off course you’re bound to the type and amount of available pins and their respective functions (e.g. analog, digital, power, tx/rx, audio out, …)

For some general boards and devices there are presets available that you can select from the compile menu.

When setting up your own device, you’ll most likely start with a breadboard or a kit like those from Synthux.

Even if you plan to skip going the cpp / arduino route and start learning here it might be worthed to watch the build guides, as they provide some guidance in how to solder and how to connect.

These basics are maybe enough to get you started:

  • connect Analog Ground AGND and Digital Ground DGND
    • Synthux pcb’s have shortcuts for this

  • depending on wether you have mono or stereo in and outputs, connect your jacks accordingly

  • use the Daisy seed pinout diagram to look up which pins you can use for your components (e.g. analog for potentiometers)

Synthux Simple So you’ve connected some potentiometers on the Synthux Simple matrix to the analog pins of the Daisy, now what? (picture from Synthux)

There already exists a comprehensive guide for pd2dsy by Takumi Ogata on the Daisy forum.

And there’s this DaisyWiki page that explains how a custom json is set up for Oopsy (Max/MSP Gen~ integration) and one DaisyWiki specific for pd2dsy

And although we’re compiling from Plugdata, the workflow is quasi the same. Even better, the process is just a bit easier as we do the compile and flashing process from within Plugdata. We do however need to make a separate file that we select in the compile window: the custom json. And that has to follow the same principles.

As a recap, the Plugdata to Daisy workflow:

  • connect/solder components to the correct Daisy board pins
  • setup a json file that tells the compiler which pins are used
  • make a patch in Plugdata with your new custom setup
  • uploading your code to the board is done by compiling:
    • Heavy Compiler Collection (hvcc) helps converting your code to C++

The Heavy compiler will output an error when there are spaces in the path or in the file names. This also applies to any subpatches you might use, or if you are exporting/saving your compiled patch to disk.

Do not use spaces in file names or in the paths, do not use capital letters in your custom components names

Custom json for a custom Daisy setup

The custom json file will be used in the compile screen where we select it as our custom board under “Target board”.

There are already some board configurations available in the presets, e.g. Electrosmith’s own Pod, Patch(init), there’s also a Synthux Simple board.

In this websites examples we’ll use the Synthux Simple PCB pins. Note that your build doesn’t need to use the exact naming of the components, the custom json can have any name.

Custom naming:

  • You can name your knobs etc. how you want, just don’t use CAPS or spaces.
    • it could be myfatfilter instead of knob1
  • You can choose a custom name for your board
  • You can choose the filename of the custom json
    • again no spaces!
  1. We make a custom json file (you can do this in a text editor)
  2. In this file we tell the compiler to which pins our components are connected.
  3. We specify what kind of component we’re using (fader, switch, …)

Here’s a basic file with a few components setup.

{
   "name": "myCustomDaisySynthFX",
   "som": "seed",
   "audio": {
     "channels": 2
   },

   "components": {
       "faderleft": {
           "component": "AnalogControl",
           "pin": 21
       },
       "knob1": {
           "component": "AnalogControl",
           "pin": 16
       },
       "toggle2up": {
           "component": "Switch",
           "pin": 7
       },
       "toggle2down": {
           "component": "Switch",
           "pin": 6
       },
       "recled": {
           "component": "Led",
           "pin": 23
       }


   }
}

This file has some info at the top about our board.

E.g. the type of the connected board is a seed, as in Daisy Seed:

   "som": "seed"

When using other types of things connected to the board, they get a separate section. E.g. a led driver or the MPR121 touch sensor.

   "parents": {
     "mpr121_driver": {
       "component": "Mpr121"
       }
   }

And then follows a list with the components and their pin types in the section "components": {

e.g. the analog potentiometers like knobs and faders:

       "faderleft": {
           "component": "AnalogControl",
           "pin": 21
       }

By listing this correctly the right setup for the type of pins will be setup for you.

If you’ve used Arduino’s think of the term pullup resistor.

The Daisy seed has a few pins that can have multiple setups so we need to tell the hardware how to activate or handle them.

Therefore we need to verify the type of pin we need: e.g. for a potentiometer we need an Analog pin.

Pin numbers

Pin numbers can become confusing, therefor I’ve made this overview table.

Pins Table overview

Follow this link to the spreadsheet showing the pin numbers used on/in the Daisy board, Plugdata, Synthux, …

When you’re making your own board it can be a handy tool to make your own copy and list your own connections and custom names.

Here’s a part of that linked table with the pins of the Simple Touch and some custom setup as an example:

Daisy seed pin numbers on the board Daisy pin names digital Daisy pin names analog Pin names Synthux Pin numbers for Simple Touch to use in Plugdata Simple touch mpr121 Description Custom names in my custom json see my notes here:
7 D6   S07 6 switch vert down toggle2down
8 D7   S08 7 switch vert up toggle2up
9 D8   S09 8 switch hor left toggle1left
10 D9   S10 9 switch hor right toggle1right
             
20 A GND A GND A GND   A GND  
21 3V3 Analog 3V3 Analog 3V3 Analog   3V3 Analog  
22 D15 A0 S30 15 pot 0 bottom left knob0
23 D16 A1 S31 16 pot 1 top left knob1
24 D17 A2 S32 17 pot 2 top knob2
25 D18 A3 S33 18 pot 3 top knob3
26 D19 A4 S34 19 pot 4 top right knob4
27 D20 A5 S35 20 pot 5 bottom right knob5
28 D21 A6 S36 21 fader left faderleft
29 D22 A7 S37 22 fader right faderright
30 D23 A8   23    
31 D24 A9        

Synthux is using the ‘S’ number as a way to refer to the connections on their PCB. This is convenient for allowing to easily mount the Daisy on the back of the Simple PCB.

Types of components and the way they communicate

In the examples of the components in the next chapter you’ll find the json instructions for each specific component.

Simple components footprint illustration from Synthux website

There’s a full list made by Electrosmith with all the supported components and all the parameters and ways you can receive or send info from and to them.

In Plugdata you will need things like float numbers, or you might need a bang, which is a trigger that activates something.

For example, the standard message a toggle switch, which is basically a type of button, will send is a bang. However we also have the option to add something to our name of the switch so Daisy will send a different type of message. The Switch has the options _fall for when a pin gets disconnected. Or a _press function that will send a specific type of message, a float of either 0 or 1.

Plugdata Toggle Switches _press _fall

Switch — Returns a bang on the signal’s rising edge (i.e. when the switch is actuated).
Switch _press Returns a float representing the current state (1 = pressed, 0 = not pressed)
Switch _fall Returns a bang on the signal’s falling edge (i.e. when the switch is released).

Components can send different types of messages by adding strings to their names in plugdata.

  • See the full list on the pd2dsy Github page
  • In the examples on this site we’ll demonstrate some of these

Aliases

It is possible to refer to your components by using aliases which you setup in the json file.

See this excerpt of code that is used in custom_json_example.json from pd2dsy on their Github

      "aliases": {
        "gate": "gatein1",
        "gate1": "gatein1",
        "gate2": "gatein2",
        "cvout": "cvout1",
        "encswitch": "encoder_rise",
        "enp": "encoder_press",
        "press": "encoder_press",
        "knob": "knob1",
        "ctrl": "knob1",
        "ctrl1": "knob1",
        "ctrl2": "knob2",
        "ctrl3": "knob3",
        "ctrl4": "knob4"
      }

Note that for the encoder the _rise and _press have been added inside the json already, making them available in Plugdata by the alias.

These details could help you make your patch more readable or clearly defined.

Download / link / full example

Though you’ll probably end up tweaking or writing your own, there are a few pre-made versions of the custom json files you can find. Two full examples are on the end of this page.

pd2dsy

Though some stuff is slightly outdated compared to the workflow you get via Plugdata, many valuable info can be found here:

json2daisy

The Utility for converting JSON board definitions into valid, libDaisy compatible C++ board support files for the Daisy platform.

You won’t need this, as its not a separate tool, but there are some examples for the different Elecrosmith boards/configurations like Pod, Patch, Field, …

json2daisy resources on Github has all the Electrosmith configurations.

Simple.json (Synthux)

Full json file ‘Simple’ that is included in Plugdata can be downloaded from Github

Note: This is the file from plugdata’s Github but I’ve added Toggle Switches on pins 6 to 9 at the end:

{
    "name": "Simple",
    "som": "seed",
    "defines": {
        "OOPSY_TARGET_HAS_MIDI_INPUT": 1
    },
    "audio": {
        "channels": 2
    },
    "components": {
        "knob1": {
            "component": "AnalogControl",
            "pin": 15
        },
        "knob2": {
            "component": "AnalogControl",
            "pin": 16
        },
        "knob3": {
            "component": "AnalogControl",
            "pin": 17
        },
        "knob4": {
            "component": "AnalogControl",
            "pin": 18
        },
        "knob5": {
            "component": "AnalogControl",
            "pin": 19
        },
        "knob6": {
            "component": "AnalogControl",
            "pin": 20
        },
        "knob7": {
            "component": "AnalogControl",
            "pin": 21
        },
        "knob8": {
            "component": "AnalogControl",
            "pin": 22
        },
        "knob9": {
            "component": "AnalogControl",
            "pin": 23
        },
        "knob10": {
            "component": "AnalogControl",
            "pin": 24
        },
        "knob11": {
            "component": "AnalogControl",
            "pin": 25
        },
        "knob12": {
            "component": "AnalogControl",
            "pin": 28
        },
        "toggle1left": {
           "component": "Switch",
           "pin": 8
       },
       "toggle1right": {
           "component": "Switch",
           "pin": 9
       },
       "toggle2up": {
           "component": "Switch",
           "pin": 7
       },
       "toggle2down": {
           "component": "Switch",
           "pin": 6
       }
    },
    "aliases": {
        "knob": "knob1"
    }
}

Synthux Simple Touch - jonwtr - setting up MPR121 Touch Sensor

This is the version I’m using. Note that for this to work you have to edit the ‘mother-file’ because of a bug the pins are not setup correct. To change the main json definition file you can do this:

Edit a part of the toolchain json components definition file

To get a working mpr121 edit a part of the toolchain json components definition file / might get fixed

  • This is not ‘normal’ and is supposed to work without the edit;

  • this bug has been reported: Bug: mpr121 pin setup incorrect

  • currently the file in question is causing an error referring to wrong pins
    • mpr121 touch sensor is supported, however seems to give a pin error:
    • Error c2daisy: 'pin_scl’
  • We need to edit the file that contains the mpr121 code and is located in the installed toolchain:
    • edit code in the json file component_defs.json
    • on my windows machine it’s here: C:\Users\gebruiker\Documents\plugdata\Toolchain\usr\bin\Heavy\json2daisy\resources\component_defs.json
  • Change the first line “map_init”:
    • Note I’ve added a few extra lines to easily see where it’s located
Original code:
--------------
"Mpr121": {
		"map_init": "daisy::Mpr121I2CTransport::Config {name}_config;\n    {name}_config.periph = {periph};\n    {name}_config.speed = {speed};\n    {name}_config.scl = som.GetPin({pin_scl});\n    {name}_config.sda = som.GetPin({pin_sda});\n    {name}_config.dev_addr = {address};\n    daisy::Mpr121I2C::Config {name}_main_conf;\n    {name}_main_conf.transport_config = {name}_config;\n    {name}_main_conf.touch_threshold = {touch_threshold};\n    {name}_main_conf.release_threshold = {release_threshold};\n    {name}.Init({name}_main_conf);",
		"typename": "daisy::Mpr121I2C",
		"direction": "in",
		"pin": "scl,sda",

delete the part referring to the pins in the “map_init” line 558, leave the line “pin” as is:

delete: {name}_config.scl = som.GetPin({pin_scl});\n {name}_config.sda = som.GetPin({pin_sda});\n

Altered code:
-------------
"Mpr121": {
		"map_init": "daisy::Mpr121I2CTransport::Config {name}_config;\n    {name}_config.periph = {periph};\n    {name}_config.speed = {speed};\n     {name}_config.dev_addr = {address};\n    daisy::Mpr121I2C::Config {name}_main_conf;\n    {name}_main_conf.transport_config = {name}_config;\n    {name}_main_conf.touch_threshold = {touch_threshold};\n    {name}_main_conf.release_threshold = {release_threshold};\n    {name}.Init({name}_main_conf);",
		"typename": "daisy::Mpr121I2C",
		"direction": "in",
		"pin": "scl,sda",

This part mpr121_driver will now load correctly.

{
   "name": "SimpleTouch",
   "som": "seed",
   "defines": {
    "OOPSY_TARGET_HAS_MIDI_INPUT": 1
   },
   "audio": {
     "channels": 2
   },

   "parents": {
     "mpr121_driver": {
       "component": "Mpr121"
       }
   },

    "components": {
       "faderleft": {
           "component": "AnalogControl",
           "pin": 21
       },
       "faderright": {
           "component": "AnalogControl",
           "pin": 22
       },
       "knob0": {
           "component": "AnalogControl",
           "pin": 15
       },
       "knob1": {
           "component": "AnalogControl",
           "pin": 16
       },
       "knob2": {
           "component": "AnalogControl",
           "pin": 17
       },
       "knob3": {
           "component": "AnalogControl",
           "pin": 18
         },
       "knob4": {
           "component": "AnalogControl",
           "pin": 19
       },
       "knob5": {
           "component": "AnalogControl",
           "pin": 20
       },
       "toggle1left": {
           "component": "Switch",
           "pin": 8
       },
       "toggle1right": {
           "component": "Switch",
           "pin": 9
       },
       "toggle2up": {
           "component": "Switch",
           "pin": 7
       },
       "toggle2down": {
           "component": "Switch",
           "pin": 6
       },
       "recled": {
        "component": "Led",
        "pin": 23
       },
       "noiseled": {
            "component": "Led",
            "pin": 24
    }
       
  }

}

Back to top

This site was made by jonwtr based on documentation and other guides found at various sources such as: Electrosmith forum, Daisy Discord, Plugdata website and Discord, Synthux.academy website and Discord, ...

Edit this page on GitHub