Is a lightweight library for "Wireless GamePad V2.0 for Arduino" from DF-Robot (https://www.dfrobot.com/product-858.html). The motivation for writing this application and library was the dissatisfaction with provided code from DF-Robot.
The incoming and outcomming messages will be transmitted in a binary format, which reduces the messages lengths to a minimum required data.
Dependencies: MegunoLink-Library is required, and can be found here: https://github.com/Megunolink/MLP. I was too lazy to write my own Exponential Filter so I used MegunoLink-Library. Therefore many thanks to MegunoLink for providing such a well written library! More Information about the filter can be found here: https://www.megunolink.com/documentation/arduino-libraries/exponential-filter/.
Features:
- Messages are received and transmitted in a binary format.
- Code in main (setup() & loop()) is reduced to the minimum.
- Easy to use Class (GamePadCtrl) to get/set Input-/Output-Controls.
- Auto calibration for Analog-Sticks at startup.
- Noise filtering for Analog-Sticks.
- Analog-Stick's can be mapped to a user defined lower and upper bound.
- Calculates a CRC8-Checksum.
Naming-Convention:
- Input-Controls: All kind of Inputs of the Gamepad (Buttons and Joysticks), which the user of the Gamepad presses.
- Output-Controls: All kind of Outputs of the Gamepad (Vibration and User-LED), which can be controlled from Outside.
Files:
- GamePadMsg.h: Contains data structures to store Input-/Output-Controls
- GamePadPins.h: Pin-Definitions of Gamepad.
- GamePadCtrl.h/.cpp: Class to update & transmit/receive Input-/Output-Controls
- GamePad.ino: Main program.
- Initializes the Pins
- Calibrates the Analog-Sticks
- Measures the first i.e. 75 (ANALOG_SETTLE_MEASUREMENTS) values to give the filter time to settle down.
- The filtered value is the determined Analog-Stick-Center-Value. -> Therefore don't touch the Analog-Sticks at Startup
- Vibrates 500ms (START_UP_DELAY_MS) when startup is finished.
Attention: The content of the structures is little-endian, therefore the receiver (and sender) of the Gamepad-Input-/Output-Controls should consider this!!!
GamePadMsgHeader:
| Name | Type | Size (Bytes) | Value | Description |
|---|---|---|---|---|
| magic | uint8_t | 1 | 0x66 | Just an identifier to recognize this message as our own. |
| cmd | uint8_t | 1 | 0x01/0x10 | GPMH_CMD_INP (0x01)/GPMH_CMD_OUT(0x10); Command-Identifier; |
| length | uint8_t | 1 | 0x01-0xFF | Length of the Message (Payload) |
| crc8 | uint8_t | 1 | 0x01-0xFF | CRC8 Checksum |
GamePadInpCtr:
| Name | Type | Size (Bytes) | Value | Description |
|---|---|---|---|---|
| leftStickX | int8_t | 1 | 0x00-0xFF | X-Value of Left-Analog-Stick |
| leftStickY | int8_t | 1 | 0x00-0xFF | Y-Value of Left-Analog-Stick |
| rightStickX | int8_t | 1 | 0x00-0xFF | X-Value of Right-Analog-Stick |
| rightStickY | int8_t | 1 | 0x00-0xFF | Y-Value of Right-Analog-Stick |
| buttons | uint16_t | 2 | 0x0000-0xFFFF | Button-States; Every button is represented by a Bit |
buttons-definition:
| Name | Offset | Button |
|---|---|---|
| select | 0x0 | Select |
| start | 0x1 | Start |
| up | 0x2 | Up-Arrow |
| left | 0x3 | Left-Arrow |
| down | 0x4 | Down-Arrow |
| right | 0x5 | Right-Arrow |
| b1 | 0x6 | Button-1/Triangle |
| b2 | 0x7 | Button-2/Circle |
| b3 | 0x8 | Button-3/Cross |
| b4 | 0x9 | Button-4/Square |
| l1 | 0xA | L1 |
| l2 | 0xB | L2 |
| l3 | 0xC | L3 |
| r1 | 0xD | R1 |
| r2 | 0xE | R2 |
| r3 | 0xF | R3 |
GamePadOutCtr:
| Name | Type | Size (Bytes) | Value | Description |
|---|---|---|---|---|
| cmds | uint8_t | 1 | 0x00-0x01 | Output-Control-States; Every output is a Bit |
cmd-definition:
| Name | Offset | Output |
|---|---|---|
| vibration | 0x0 | Turns vibration on/off |
| _reserved | 0xE | Not used! Reserved for future usage. |
NOTE: The LED is not really controllable from outside, because the electronic turns it on and off if serial-data is received.