DigitalSandbox PicoBoard

Contributors: bri_huang

Uploading Firmware

First, we need to upload firmware to the digital sandbox so that it mimics the same packet information as on the PicoBoard. The original C code for the PicoBoard is available on GitHub, but this code does not work directly in the Arduino programming IDE.

We ported this code base over and made a few adjustments based on the difference of pin configurations on the digital sandbox.

This code reads all of the sensors on the Digital Sandbox, creates data "packets" emulating the PicoBoard, and sends this over to your computer -- to be read in by Scratch.

PicoBoard Arduino Code

language:c
    // DigitalSandboxPico
//
// PicoBoard Firmware modified for the DigitalSandBox 
// Arduino Learning Platform.
// Ported over from original C code.
//
// Modified by: Brian Huang, Sparkfun Electronics
// Date:  August 7, 2014

#define SCRATCH_DATA_REQUEST 0x01

char request = 0;
unsigned int sensor_value = 0;
char data_packet[2]= "";

int SLIDER = A3; // Slider on DS Board
int SOUND = A2;  // Microphone on DS Board
int LIGHT = A1;  // Light Detector on DS Board
int BUTTON = 12; // Push Button on DS Board

int RA = A0; // Temp
int RB = 2;  // Switch
int RC = 3;  // D3 -- Side Port 
int RD = A4; // A4 -- Top Port

void setup()
{
  pinMode(BUTTON, INPUT_PULLUP);  // enable internal pull-up resistor
  pinMode(RB, INPUT_PULLUP);  // enable internal pull-up resistor
  Serial.begin(38400);
}

void loop()
{
  request = Serial.read();
  if(request == SCRATCH_DATA_REQUEST)
  {
    // send the ID packet
    buildScratchPacket(data_packet, 15, 0x04);
    sendScratchPacket(data_packet);

    // Do not change the order of this sequence. Scratch expects the data 
    // to be organized in this order.

    //Read/Report channel 0 (Resistance-D)
    sensor_value=analogRead(RD);
    buildScratchPacket(data_packet, 0, sensor_value);
    sendScratchPacket(data_packet);

    //Read/Report Channel 1 (Resistance-C)
    sensor_value=analogRead(RC);
    buildScratchPacket(data_packet, 1, sensor_value);
    sendScratchPacket(data_packet);

    //Read/Report Channel 2 (Resistance-B)
    sensor_value=1023*digitalRead(RB);
    buildScratchPacket(data_packet, 2, sensor_value);
    sendScratchPacket(data_packet);         

    //Read/Report Channel 3 (Button)
    sensor_value = 1023*(1 - digitalRead(BUTTON));
    buildScratchPacket(data_packet, 3, sensor_value);
    sendScratchPacket(data_packet); 

    //Read/Report Channel 4(Resistance-A)
    sensor_value=analogRead(RA);
    buildScratchPacket(data_packet, 4, sensor_value);
    sendScratchPacket(data_packet);     

    //Read/Report Channel 5(LIGHT)
    sensor_value=1023 - analogRead(LIGHT);
    buildScratchPacket(data_packet, 5, sensor_value);
    sendScratchPacket(data_packet); 

    //Read/Report Channel 6(Sound)
    sensor_value=analogRead(SOUND);
    buildScratchPacket(data_packet, 6, sensor_value);
    sendScratchPacket(data_packet);         

    //Read/Report Channel 7(Slider)
    sensor_value=analogRead(SLIDER);
    buildScratchPacket(data_packet, 7, sensor_value);
    sendScratchPacket(data_packet);
  }
}

void buildScratchPacket(char * packet, int channel, int value)
{
  char upper_data=(char)((value&(unsigned int)0x380)>>7);   //Get the upper 3 bits of the value
  char lower_data=(char)(value&0x7f);   //Get the lower 7 bits of the value
  *packet++=((1<<7)|(channel<<3)|(upper_data));
  *packet++=lower_data;
}

void sendScratchPacket(char * packet)
{
  Serial.write(*packet++);
  delayMicroseconds(400);
  Serial.write(*packet++);
  delayMicroseconds(400);
}

Copy-paste this code into your Arduino IDE. Select either Lilypad w/ ATMega328 as your board type or Digital Sandbox (if you are using our version of Arduino).