Add code / model for a limit switch

kiln/stepper.py

@@ -19,7 +19,7 @@ class Stepper(threading.Thread):
         [0,0,1,1],
         [1,0,0,1]]
 
-    def __init__(self, pin1=5, pin2=6, pin3=13, pin4=19, timeout=1):
+    def __init__(self, pin1=5, pin2=6, pin3=13, pin4=19, timeout=1, home_pin=None):
         super(Stepper, self).__init__()
         self.daemon = True
 
@@ -32,9 +32,11 @@ class Stepper(threading.Thread):
         GPIO.setup(pin2, GPIO.OUT)
         GPIO.setup(pin3, GPIO.OUT)
         GPIO.setup(pin4, GPIO.OUT)
+        self.home_pin = home_pin
+        GPIO.setup(home_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
 
-        self.phase = 0
         self.timeout = timeout
+        self.home()
         self.start()
 
     def stop(self):
@@ -56,6 +58,18 @@ class Stepper(threading.Thread):
         self.queue.put((num, speed, block))
         self.finished.wait()
 
+    def home(self):
+        if self.home_pin is None:
+            raise ValueError("No homing switch defined")
+
+        while GPIO.input(self.home_pin):
+            for i in range(len(self.pattern)):
+                for pin, out in zip(self.pins, self.pattern[i]):
+                    GPIO.output(pin, out)
+                time.sleep(1. / 150.)
+
+        self.phase = 0
+
     def run(self):
         try:
             step, speed, block = self.queue.get()
@@ -202,7 +216,8 @@ class Regulator(threading.Thread):
 
     def off(self, block=True):
         logger.info("Shutting off gas")
-        self.stepper.step(-self.current, self.speed, block=block)
+        #self.stepper.step(-self.current, self.speed, block=block)
+        self.stepper.home()
         self.current = 0
 
     def set(self, value, block=False):

models/regulator.scad

@@ -40,11 +40,42 @@ module zipties() {
 }
 
 module holder() {
-	difference() {
-		intersection()	 {
-			translate([0,0,-3.3-thick]) scale([1,1.4]) cylinder(r=36+thick, h=16, $fn=128);
-			translate([36+thick-20,-zip_pos-3-thick, -10]) cube([20, 2*zip_pos+6+2*thick,20]);
+	width = 2*zip_pos+6+2*thick;
+
+	module slot(length) {
+		hull() {
+			cylinder(r=1, h=6);
+			translate([length,0]) cylinder(r=1, h=6);
 		}
+	}	
+
+	//translate([18,-width/2, -3.3-thick+16+32-6]) cube([12, 20, 6]);
+	difference() {
+		union() {
+			//main body
+			intersection()	 {
+				translate([0,0,-3.3-thick]) scale([1,1.4]) cylinder(r=36+thick, h=16, $fn=128);
+				translate([36+thick-20,-width/2, -10]) cube([20, width,20]);
+			}
+
+			//switch tab
+			intersection() {
+				translate([0,0,-3.3-thick]) scale([1, 1.4]) difference() {
+					cylinder(r=36+thick, h=16+34+3, $fn=128);
+					translate([0,0,-1]) cylinder(r=36, h=16+32+3-2,$fn=128);
+				}
+				translate([36+thick-20, -width/2, -3.3-thick]) cube([50, 20, 16+32+4]);
+			}
+		}
+		//Screw slots for switch
+		translate([20,-width/2+10-9.5/2, -3.3-thick+16+32-1]) {
+			translate([3,0]) slot(5);
+			translate([3,9.5]) slot(5);
+		}
+	
+		//Slot for wire to ensure no gear tangling
+		translate([20, -width/2+8.5,-3.3-thick+16+32-3]) cube([50, 3, 3]);
+
 		regulator();
 		zipties();
 	}