Feature compressor

Marlin/Configuration.h

@@ -137,7 +137,7 @@
 #define TEMP_SENSOR_0 6
 #define TEMP_SENSOR_1 0
 #define TEMP_SENSOR_2 0
-#define TEMP_SENSOR_BED 0 //we're not using heated bed
+#define TEMP_SENSOR_BED 1000 //we are treating the pressure sensor as a bed temp sensor.
 
 // This makes temp sensor 1 a redundant sensor for sensor 0. If the temperatures difference between these sensors is to high the print will be aborted.
 //#define TEMP_SENSOR_1_AS_REDUNDANT
@@ -154,15 +154,15 @@
 #define HEATER_0_MINTEMP 5
 #define HEATER_1_MINTEMP 5
 #define HEATER_2_MINTEMP 5
-#define BED_MINTEMP 5
+#define BED_MINTEMP -1 // 0 pressure is a valid reading
 
 // When temperature exceeds max temp, your heater will be switched off.
 // This feature exists to protect your hotend from overheating accidentally, but *NOT* from thermistor short/failure!
 // You should use MINTEMP for thermistor short/failure protection.
 #define HEATER_0_MAXTEMP 235
 #define HEATER_1_MAXTEMP 235
 #define HEATER_2_MAXTEMP 235
-#define BED_MAXTEMP 150
+#define BED_MAXTEMP 500
 
 // If your bed has low resistance e.g. .6 ohm and throws the fuse you can duty cycle it to reduce the
 // average current. The value should be an integer and the heat bed will be turned on for 1 interval of
@@ -216,7 +216,11 @@
 // If this is enabled, find your own PID constants below.
 //#define PIDTEMPBED
 //
-//#define BED_LIMIT_SWITCHING
+#define BED_LIMIT_SWITCHING
+
+// Override the high and low values since we are using the bed temp for pressure control, and a high reading means a high temp
+#define HEATER_BED_RAW_HI_TEMP 16383
+#define HEATER_BED_RAW_LO_TEMP 0
 
 // This sets the max power delivered to the bed, and replaces the HEATER_BED_DUTY_CYCLE_DIVIDER option.
 // all forms of bed control obey this (PID, bang-bang, bang-bang with hysteresis)

Marlin/pins.h

@@ -2224,7 +2224,7 @@ DaveX plan for Teensylu/printrboard-type pinouts (ref teensylu & sprinter) for a
 #define Z_MS2_PIN 67
 
 #define HEATER_BED_PIN 3
-#define TEMP_BED_PIN 2
+#define TEMP_BED_PIN 3 // Connect the pressure sensor to pin A3 on the Rambo
 
 #define HEATER_0_PIN  9
 #define TEMP_0_PIN 0

Marlin/thermistortables.h

@@ -1097,6 +1097,35 @@ const short temptable_70[][2] PROGMEM = {
 };
 #endif
 
+#if (THERMISTORHEATER_0 == 1000) || (THERMISTORHEATER_1 == 1000)  || (THERMISTORHEATER_2 == 1000) || (THERMISTORBED == 1000) //pressure sensor LUT
+// Lookup table to convert analog values to pressure values.
+// Pressure values are in 10ths of PSIs (i.e 213 = 21.3 PSI).
+const short temptable_1000[][2] PROGMEM = {
+   {1*OVERSAMPLENR,    0},
+   {103*OVERSAMPLENR,  0},
+   {115*OVERSAMPLENR,  6},
+   {160*OVERSAMPLENR,  34},
+   {180*OVERSAMPLENR,  47},
+   {200*OVERSAMPLENR,  58},
+   {240*OVERSAMPLENR,  83},
+   {260*OVERSAMPLENR,  96},
+   {300*OVERSAMPLENR,  120},
+   {350*OVERSAMPLENR,  150},
+   {400*OVERSAMPLENR,  181},
+   {450*OVERSAMPLENR,  211},
+   {500*OVERSAMPLENR,  242},
+   {550*OVERSAMPLENR,  273},
+   {600*OVERSAMPLENR,  304},
+   {650*OVERSAMPLENR,  332},
+   {700*OVERSAMPLENR,  364},
+   {750*OVERSAMPLENR,  394},
+   {800*OVERSAMPLENR,  425},
+   {830*OVERSAMPLENR,  443},
+};
+
+#endif
+
+
 #define _TT_NAME(_N) temptable_ ## _N
 #define TT_NAME(_N) _TT_NAME(_N)