Hello, everyone,

I am using an Arduino board programmed to send arrow-key keystrokes to run my Scratch game. The Arduino programming is working fine.

My question:
When I program the arrow keys using the brown event blocks (When up arrow pressed, etc.), it works fine.
BUT
When I program the arrow keys using a blue sensing block within an IF block (IF Key <up arrow pressed?>), it doesn't work reliably at all.

Why is this? What is the difference between the two methods?

Thanks!
Jesse

jheetland wrote:

Hello, everyone,

I am using an Arduino board programmed to send arrow-key keystrokes to run my Scratch game. The Arduino programming is working fine.

My question:
When I program the arrow keys using the brown event blocks (When up arrow pressed, etc.), it works fine.
BUT
When I program the arrow keys using a blue sensing block within an IF block (IF Key <up arrow pressed?>), it doesn't work reliably at all.

Why is this? What is the difference between the two methods?

Thanks!
Jesse

If you are using the Keyboard.press() function on your Arduino, you probably have to just have it pressed for longer because < key pressed?> only checks if the key is pressed at that exact instant. If you want it to work correctly, just put a delay(1000) in between the Keyboard.press() and the Keyboard.release(). Another option is to wait for the button to be released and then do a Keyboard.release().

Edit: It'd be cool to see the sketch (and project) once you're done since I have an Arduino too

Here is the sketch for the Arduino arrow keys. It is based on the capacitive_sense_library_demo, since I thought it would be cooler to set it up as a capacitive touch sensor (i.e. square of aluminum foil!) rather than a button completing a circuit.
I will try your edits and see if they work. Thanks!

(Basic setup is for each pair of pins (2&3, 4&5, etc.) there is a 100K ohm resistor, leading out from that resistor is another wire taped to a piece of foil. When you touch the foil, the capacitance changes. The sketch includes serial printing of the values of each of the four sensors.)

/*
* CapacitiveSense Library Demo Sketch
* Paul Badger 2008
* Uses a high value resistor e.g. 10M between send pin and receive pin
* Resistor effects sensitivity, experiment with values, 50K - 50M. Larger resistor values yield larger sensor values.
* Receive pin is the sensor pin - try different amounts of foil/metal on this pin

CapacitiveSense.h - Capacitive Sensing Library for 'duino / Wiring
https://github.com/PaulStoffregen/CapacitiveSensor
http://www.pjrc.com/teensy/td_libs_CapacitiveSensor.html
http://playground.arduino.cc/Main/CapacitiveSensor
Copyright © 2009 Paul Bagder
*/

// Edited toward using this as a KB/mouse controller by Jesse Heetland

#include <CapacitiveSensor.h>
#include “Keyboard.h”
#include “Mouse.h” // if you later want to use this sketch for mouse control

// The following functions do…something I don't quite understand yet
CapacitiveSensor cs_2_3 = CapacitiveSensor(2,3); // Used for up
CapacitiveSensor cs_4_5 = CapacitiveSensor(4,5); // Used for down
CapacitiveSensor cs_6_7 = CapacitiveSensor(6,7); // Used for left
CapacitiveSensor cs_8_9 = CapacitiveSensor(8,9); // Used for right

// Declare variables
long sensor_reading_up;
long sensor_reading_down;
long sensor_reading_left;
long sensor_reading_right;
int not_touched_value = 10; // 10 is a good number to act as a “not touched” value, chosen by looking at the serial output


void setup()
{
Serial.begin(9600); // Open serial port for outputting data
Keyboard.begin(); // Needed to allow outputting keyboard characters
// Mouse.begin(); // This would be needed if you are going to use this program for mouse control
}

void loop()
{
sensor_reading_up = cs_2_3.capacitiveSensor(30);
sensor_reading_down = cs_4_5.capacitiveSensor(30);
sensor_reading_left = cs_6_7.capacitiveSensor(30);
sensor_reading_right = cs_8_9.capacitiveSensor(30);

Serial.print(sensor_reading_up); // This prints the values of the up sensor
Serial.print(“\t”); // tab
Serial.print(sensor_reading_down); // This prints the values of the down sensor
Serial.print(“\t”); // tab
Serial.print(sensor_reading_left); // This prints the values of the left sensor
Serial.print(“\t”); // tab
Serial.print(sensor_reading_right); // This prints the values of the right sensor
Serial.print(“\n”); // new line


// HERE IS THE SECTION WHERE IT SENDS THE BUTTON PRESSES:
if (sensor_reading_up > not_touched_value) {
Keyboard.press(218); // up button
}
if (sensor_reading_down > not_touched_value) {
Keyboard.press(217); // down button
}
if (sensor_reading_left > not_touched_value) {
Keyboard.press(216); // left button
}
if (sensor_reading_right > not_touched_value) {
Keyboard.press(215); // right button
}
Keyboard.releaseAll(); // quit pressing whatever key was just pressed

delay(10); // 10 ms arbitrary delay to limit data to serial port
}