Sparkbox, another BT pedal for the Spark

SparkBox V0.56

This is a Dev Kit 32 version of SparkBox. SparkBox is another BT pedal for the Positive Grid Spark 40. I only needed the functionality of the simpler BT pedals. However many of them use captured hex chunks to communicate with the Spark, or were Python based. Instead I wanted to use Paul Hamshere's amazing code to create and process real messages. Also I wanted to extend the functionality a bit and make a pretty UI.

Functions

  • Expression pedal input on D34 for altering the current parameter or on/off switch
  • Uses BLE so that it can be used with music function of the Spark app
  • Allows connection of the app for full simultaneous control
  • Switch presets either on footswitch, app or Spark to update display
  • Switch on and off all four major effects dynamically
  • Graphically display the effect state on the display
  • Supports 4-button pedals
  • Hold down any switch for 1s to switch between Effect mode and Preset mode
  • Battery level indicator on UI
  • BLE RSSI inidcator

Arduino libraries and board versions

Under Files->Preferences->Additional Boards Manager URLs, enter the following:

Under Tools->Board->Board manager ensure that you have the following version:

  • ESP32 by Espressif 1.0.4 (SparkBox - ESP32 Dev Module)

Under Tools->Manage Libraries nsure that you have the following libraries and versions:

  • ThingPulse SSD1306 driver 4.2.1 (SparkBox)
  • NimBLE=Arduino 1.3.1

Compile options

Uncomment ONE battery option to match your hardware.

define BATT_CHECK_0

You have no mods to monitor the battery, so it will show empty (default).

define BATT_CHECK_1

You are monitoring the battery via a 2:1 10k/10k resistive divider to GPIO23. You can see an accurate representation of the remaining battery charge and a kinda-sorta indicator of when the battery is charging. Maybe.

define BATT_CHECK_2

You have the battery monitor mod described above AND you have a connection between the CHRG pin of the charger chip and GPIO 33. Go you! Now you have a guaranteed charge indicator too.

define EXPRESSION_PEDAL

Expression pedal define. Comment this out if you DO NOT have the expression pedal mod.

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Parts list

Item Description Link
1 Box https://www.aliexpress.com/item/32693268669.html?spm=a2g0s.9042311.0.0.27424c4dlzGiUH
2 Stomp switch https://www.aliexpress.com/item/32918205335.html?spm=a2g0s.9042311.0.0.27424c4dszp4Ie
3 ESP-WROOM-32U module https://www.aliexpress.com/item/32864722159.html?spm=a2g0s.9042311.0.0.27424c4dlzGiUH
4 LCD screen https://www.ebay.com.au/itm/333085424031
5 BT antenna https://www.aliexpress.com/item/4001054693109.html?spm=a2g0s.9042311.0.0.27424c4dlzGiUH and https://www.ebay.com.au/itm/233962468558
6 USB extension https://www.aliexpress.com/item/32808991941.html?spm=a2g0s.9042311.0.0.27424c4dlzGiUH
7 Power switch https://www.jaycar.com.au/dpdt-miniature-toggle-switch-solder-tag/p/ST0355
8 DC input jack https://www.jaycar.com.au/2-5mm-bulkhead-male-dc-power-connector/p/PS0524
9 Pedal jack https://www.jaycar.com.au/6-5mm-stereo-enclosed-insulated-switched-socket/p/PS0184
10 LiPo battery https://www.ebay.com.au/itm/133708965813
11 LiPo charger https://www.ebay.com.au/itm/161821599467
12 LiPo booster https://www.jaycar.com.au/arduino-compatible-5v-dc-to-dc-converter-module/p/XC4512
13 9V to 5V converter https://www.ebay.com.au/itm/303839459634
14 Glass window (opt) https://www.aliexpress.com/item/4000377316108.html?spm=a2g0s.12269583.0.0.1a1e62440DlgU2

More information on the Sparkbox GitHub page

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