- Added support for level control input & state LEDs

- Added example wiring scheme

README.md

@@ -2,12 +2,18 @@
 
 This is a very simple tool to limit the Twizy charge current if you don't have an OVMS.
 
-It can currently only limit the charge current to a fixed level (defined in the config file).
+It can limit the charge current to a fixed level (defined in the config file) or use a
+coded rotary switch or simple DIP switch for dynamic level adjustment. It can signal
+the charging state and active throttling by LEDs.
+
+See [wiring scheme](extras/Wiring.pdf) for an example using a coded rotary switch.
 
 The Arduino needs to be connected to the Twizy CAN bus during the charge process to be able
 to actively overwrite the charge current control frames.
 
-Note: using an interrupt capable CAN shield is highly recommended.
+Note: using an interrupt capable CAN shield is highly recommended. No attempt at
+reducing the Arduino current consumption is made, include a power switch or fork and
+extend the code for sleep mode (and send me a pull request).
 
 
 ## Info

TwizyChargeThrottle/TwizyChargeThrottle.ino

@@ -13,12 +13,18 @@
  *  https://www.gnu.org/licenses/lgpl.html
  *  
  */
-#define TWIZY_CT_VERSION "V1.0 (2019-05-10)"
+#define TWIZY_CT_VERSION "V2.0 (2019-05-17)"
 
 #include <mcp_can.h>
 #include <mcp_can_dfs.h>
 #include "TwizyChargeThrottle_config.h"
 
+#if TWIZY_DEBUG >= 1
+  #define DEBUG1(cmd) cmd
+#else
+  #define DEBUG1(cmd)
+#endif
+
 // CAN interface:
 MCP_CAN CAN(TWIZY_CAN_CS_PIN);
 
@@ -33,12 +39,23 @@ bool charging = false;
 // Current level:
 byte level = 0;
 
+// Throttling level:
+#ifdef FIXED_LEVEL
+  const byte throttle = FIXED_LEVEL;
+#else
+  byte throttle = 0;
+  #define READ_LEVEL() \
+    ( digitalRead(IN_LEVEL_B1) \
+    | digitalRead(IN_LEVEL_B2) << 1 \
+    | digitalRead(IN_LEVEL_B4) << 2)
+#endif
+
 
 #if TWIZY_CAN_IRQ_PIN > 0
-volatile bool msgReceived = false;
-void canISR() {
-  msgReceived = true;
-}
+  volatile bool msgReceived = false;
+  void canISR() {
+    msgReceived = true;
+  }
 #endif
 
 
@@ -50,8 +67,8 @@ void setup() {
   // Init CAN interface:
   
   #if TWIZY_CAN_IRQ_PIN > 0
-  pinMode(TWIZY_CAN_IRQ_PIN, INPUT);
-  attachInterrupt(digitalPinToInterrupt(TWIZY_CAN_IRQ_PIN), canISR, FALLING);
+    pinMode(TWIZY_CAN_IRQ_PIN, INPUT);
+    attachInterrupt(digitalPinToInterrupt(TWIZY_CAN_IRQ_PIN), canISR, FALLING);
   #endif
 
   while (CAN.begin(MCP_STDEXT, CAN_500KBPS, TWIZY_CAN_MCP_FREQ) != CAN_OK) {
@@ -73,10 +90,24 @@ void setup() {
   
   CAN.setMode(MCP_NORMAL);
 
+  // Init I/O:
+
+  #ifndef FIXED_LEVEL
+    pinMode(IN_LEVEL_B1, INPUT);
+    pinMode(IN_LEVEL_B2, INPUT);
+    pinMode(IN_LEVEL_B4, INPUT);
+    throttle = READ_LEVEL();
+  #endif
+
+  pinMode(OUT_CHARGING_PIN, OUTPUT);
+  pinMode(OUT_THROTTLING_PIN, OUTPUT);
+  digitalWrite(OUT_CHARGING_PIN, LOW);
+  digitalWrite(OUT_THROTTLING_PIN, LOW);
+
   Serial.println(F("Setup done."));
 
-  Serial.print(F("Throttling configured to current level: "));
-  Serial.println((char)('0' + TWIZY_CHARGE_THROTTLE));
+  Serial.print(F("Throttling to current level: "));
+  Serial.println((char)('0' + throttle));
 }
 
 
@@ -84,9 +115,9 @@ void loop() {
   while (true) {
 
     #if TWIZY_CAN_IRQ_PIN > 0
-    // Wait for interrupt signal:
-    while (!msgReceived);
-    msgReceived = false;
+      // Wait for interrupt signal:
+      while (!msgReceived);
+      msgReceived = false;
     #endif
 
     // Process CAN read buffer:
@@ -98,12 +129,20 @@ void loop() {
         
         bool _charging = ((msgBuf[1] & 0x60) == 0x20);
         
-        #if TWIZY_DEBUG > 0
         if (_charging && !charging)
-          Serial.println(F("Charge START"));
+        {
+          digitalWrite(OUT_CHARGING_PIN, HIGH);
+          #ifndef FIXED_LEVEL
+            throttle = READ_LEVEL();
+          #endif
+          DEBUG1(Serial.println(F("Charge START")));
+        }
         else if (!_charging && charging)
-          Serial.println(F("Charge STOP"));
-        #endif
+        {
+          digitalWrite(OUT_CHARGING_PIN, LOW);
+          digitalWrite(OUT_THROTTLING_PIN, LOW);
+          DEBUG1(Serial.println(F("Charge STOP")));
+        }
         
         charging = _charging;
         level = 0;
@@ -117,31 +156,40 @@ void loop() {
         if (_level == 0xFF)
           continue; // init phase, skip
         
-        if (_level > TWIZY_CHARGE_THROTTLE)
+        if (throttle != 0 && _level > throttle)
         {
           // overwrite:
-          msgBuf[0] = TWIZY_CHARGE_THROTTLE;
+          msgBuf[0] = throttle;
           CAN.sendMsgBuf(0x155, 0, 8, msgBuf);
+          digitalWrite(OUT_THROTTLING_PIN, HIGH);
+        }
+        else
+        {
+          digitalWrite(OUT_THROTTLING_PIN, LOW);
         }
 
         #if TWIZY_DEBUG > 1
-        if (_level != level)
-        {
-          Serial.print(F("Level "));
-          if (_level > TWIZY_CHARGE_THROTTLE) {
-            Serial.print((char)('0' + _level));
-            Serial.print('>');
-            Serial.println((char)('0' + TWIZY_CHARGE_THROTTLE));
-          } else {
-            Serial.println((char)('0' + _level));
+          if (_level != level)
+          {
+            Serial.print(F("Level "));
+            if (_level > throttle) {
+              Serial.print((char)('0' + _level));
+              Serial.print('>');
+              Serial.println((char)('0' + throttle));
+            } else {
+              Serial.println((char)('0' + _level));
+            }
           }
-        }
         #endif
         
         level = _level;
       }
     }
 
+    #ifndef FIXED_LEVEL
+      throttle = READ_LEVEL();
+    #endif
+
   } // while (true)
 }
 

TwizyChargeThrottle/TwizyChargeThrottle_config.h

@@ -6,19 +6,35 @@
 #ifndef _TwizyChargeThrottle_config_h
 #define _TwizyChargeThrottle_config_h
 
-// Set the charge current throttle level here:
+// Charge current throttle levels:
+//  7 = 35 A = 2,3 kW (full power, no throttling)
 //  6 = 30 A = 2,1 kW
 //  5 = 25 A = 1,7 kW
 //  4 = 20 A = 1,4 kW
 //  3 = 15 A = 1,0 kW
 //  2 = 10 A = 0,7 kW
 //  1 =  5 A = 0,4 kW
-#define TWIZY_CHARGE_THROTTLE     5
+//  0 = no throttling
+
+// If not using a power level input, define a fixed throttling level like this:
+// #define FIXED_LEVEL               5
+// If this is defined, the power level inputs will not be used.
+
+// Power level input:
+// Use an 8 position binary coded rotary switch or a 3 pin DIP switch (or similar),
+// define the input ports used here (analog ports may be used as well):
+#define IN_LEVEL_B1               3
+#define IN_LEVEL_B2               4
+#define IN_LEVEL_B4               5
+
+// Status outputs (e.g. LEDs):
+#define OUT_CHARGING_PIN          8
+#define OUT_THROTTLING_PIN        9
 
 // Serial debug output level:
 //  1 = show charge start/stop
 //  2 = show current level changes
-#define TWIZY_DEBUG               2
+#define TWIZY_DEBUG               0
 
 // Serial interface baud rate:
 #define SERIAL_SPEED              115200
@@ -27,7 +43,7 @@
 #define TWIZY_CAN_MCP_FREQ        MCP_16MHZ
 
 // Set your CAN CS pin number here:
-#define TWIZY_CAN_CS_PIN          SS
+#define TWIZY_CAN_CS_PIN          10
 
 // Set your CAN IRQ pin here (0 = no IRQ):
 #define TWIZY_CAN_IRQ_PIN         2