writing speed is detected, and the model mayhem sets backlight according to

speed

firmware/main.c

@@ -523,6 +523,49 @@ void sendString(char* string) {
     }
 }
 
+/**
+ * Calculate an average value for the speed the keys are pressed in. The speed
+ * value is sent to the keyboard interface, the keyboard decides what to do
+ * with it.
+ * \param updates number of updates since the last call (should be in the range
+ * 0-1)
+ */
+void calculateSpeed(uint8_t updates) {
+    static uint8_t callcounter = 0;
+    static uint8_t speed = 0;
+    callcounter++;
+    if (updates > 0) {
+        // a key has been pressed
+        if (speed < 251) {
+            // it can get hotter...
+            if (callcounter < 8) {
+                speed += 4;
+            } else if (callcounter < 16) {
+                speed += 3;
+            } else if (callcounter < 24) {
+                speed += 2;
+            } else {
+                speed += 1;
+            }
+            setSpeed(speed);
+        }
+        callcounter = 0;
+    } else {
+        // no key pressed...
+        if (callcounter == 16) {
+            // ... for a long time, decrease speed value
+            if (speed > 10) {
+                speed -= 10;
+                setSpeed(speed);
+            } else if (speed > 0) {
+                speed = 0;
+                setSpeed(speed);
+            }
+            callcounter = 0;
+        }
+    }
+}
+
 /**
  * Main function, containing the main loop that manages timer- and
  * USB-functionality.
@@ -531,6 +574,7 @@ void sendString(char* string) {
 int main(void) {
     uint8_t updateNeeded = 0;
     uint8_t idleCounter = 0;
+    uint8_t updates = 0;
     wdt_enable(WDTO_2S);
     hardwareInit();
     usbInit();
@@ -545,10 +589,15 @@ int main(void) {
         usbPoll();
 
         updateNeeded = scankeys(reportBuffer, oldReportBuffer, sizeof(reportBuffer)); // changes?
+        if (updateNeeded) {
+            updates++;
+        }
 
         // check timer if we need periodic reports
         if (TIFR & (1 << TOV0)) {
             TIFR = (1 << TOV0); // reset flag
+            calculateSpeed(updates);
+            updates = 0;
             if (idleRate != 0) { // do we need periodic reports?
                 if(idleCounter > 4){ // yes, but not yet
                     idleCounter -= 5; // 22ms in units of 4ms