I tested out the driving electronics using two LEDs connected in opposing polarities, and adjusting the LM317 output to bring down the voltage so as not to burn the LEDs out.
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This is what the code looks like running. The via placement for the coils just happened to be the right size to mount a few 0603 package SMD LEDs, so I converted one of the braille module PCBs into a tester.
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The code below shows the functions I'm using to select which pin of which module to actuate. MOD_X and PIN_X are the pin numbering for the input pins of the decoder IC.
void moduleSelect(int decimalValue) {
//Ensure the input decimal value is within the valid range (1 to 8)
//numbering starts from 1, so subract
decimalValue--;
if (decimalValue >= 0 && decimalValue <= 7) {
// Calculate the binary representation of the decimal value
digitalWrite(MOD_0,(decimalValue >> 0) & 0x01);
digitalWrite(MOD_1,(decimalValue >> 1) & 0x01);
digitalWrite(MOD_2,(decimalValue >> 2) & 0x01);
} else {
digitalWrite(MOD_0,0);
digitalWrite(MOD_1,0);
digitalWrite(MOD_2,0);
}
}
void pinSelect(int decimalValue) {
//Ensure the input decimal value is within the valid range (1 to 6)
//numbering starts from 1, so subract
decimalValue--;
if (decimalValue >= 0 && decimalValue <= 5) {
// Calculate the binary representation of the decimal value
digitalWrite(PIN_0,(decimalValue >> 0) & 0x01);
digitalWrite(PIN_1,(decimalValue >> 1) & 0x01);
digitalWrite(PIN_2,(decimalValue >> 2) & 0x01);
} else {
digitalWrite(PIN_0,0);
digitalWrite(PIN_1,0);
digitalWrite(PIN_2,0);
}
}
After the pin/module is selected, the enable pins of the decoder IC are manipulated to change the polarity of the voltage across each pin.
void pinSet() {
digitalWrite(SET,1);
digitalWrite(RESET,0);
}
void pinReset() {
digitalWrite(SET,0);
digitalWrite(RESET,1);
}
void pinOff() {
digitalWrite(SET,0);
digitalWrite(RESET,0);
}
The whole code to test out the addressability of the pins is below:
// Pin configuration
const int MOD_0 = 6; // A0, A1, A2 of the 1st decoder
const int MOD_1 = 7;
const int MOD_2 = 8;
const int PIN_0 = 9; // A0, A1, A2 of the 2nd decoder
const int PIN_1 = 10;
const int PIN_2 = 11;
const int RESET = 5; // Set pin of the 1st decoder
const int SET = 4; // Reset pin of the 1st decoder
void setup() {
// Initialize Serial communication for debugging (optional)
Serial.begin(9600);
pinMode(MOD_0,OUTPUT);
pinMode(MOD_1,OUTPUT);
pinMode(MOD_2,OUTPUT);
pinMode(PIN_0,OUTPUT);
pinMode(PIN_1,OUTPUT);
pinMode(PIN_2,OUTPUT);
pinMode(SET,OUTPUT);
pinMode(RESET,OUTPUT);
}
void loop() {
moduleSelect(1);
int pin = 1;
while(true)
{
pinSelect(pin);
pinSet();
delay(500);
pinReset();
delay(500);
pinOff();
delay(500);
pin++;
if(pin > 6)
{
pin = 1;
}
}
}
void moduleSelect(int decimalValue) {
//Ensure the input decimal value is within the valid range (1 to 8)
//numbering starts from 1, so subract
decimalValue--;
if (decimalValue >= 0 && decimalValue <= 7) {
// Calculate the binary representation of the decimal value
digitalWrite(MOD_0,(decimalValue >> 0) & 0x01);
digitalWrite(MOD_1,(decimalValue >> 1) & 0x01);
digitalWrite(MOD_2,(decimalValue >> 2) & 0x01);
} else {
digitalWrite(MOD_0,0);
digitalWrite(MOD_1,0);
digitalWrite(MOD_2,0);
}
}
void pinSelect(int decimalValue) {
//Ensure the input decimal value is within the valid range (1 to 6)
//numbering starts from 1, so subract
decimalValue--;
if (decimalValue >= 0 && decimalValue <= 5) {
// Calculate the binary representation of the decimal value
digitalWrite(PIN_0,(decimalValue >> 0) & 0x01);
digitalWrite(PIN_1,(decimalValue >> 1) & 0x01);
digitalWrite(PIN_2,(decimalValue >> 2) & 0x01);
} else {
digitalWrite(PIN_0,0);
digitalWrite(PIN_1,0);
digitalWrite(PIN_2,0);
}
}
void pinSet() {
digitalWrite(SET,1);
digitalWrite(RESET,0);
}
void pinReset() {
digitalWrite(SET,0);
digitalWrite(RESET,1);
}
void pinOff() {
digitalWrite(SET,0);
digitalWrite(RESET,0);
}
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