diff --git a/ext/lcd/Draw.h b/ext/lcd/Draw.h
index 2152e94..6636e08 100644
--- a/ext/lcd/Draw.h
+++ b/ext/lcd/Draw.h
@@ -156,18 +156,21 @@ public:
 		dst.fillRect(x,y,w,h);
 	}
 
+	/** draw a horizontal line from x1 to x2 (inclusive) */
 	void drawLineHor(const Scalar x1, const Scalar x2, const Scalar y) {
-		dst.fillRect(x1,y,x2-x1,1);
+		for (Scalar x = x1; x <= x2; ++x) {dst.setPixel(x, y);}
 	}
+	
+	/** draw a vertical line from y1 to y2 (inclusive) */
 	void drawLineVer(const Scalar y1, const Scalar y2, const Scalar x) {
-		dst.fillRect(x,y1,1,y2-y1);
+		for (Scalar y = y1; y <= y2; ++y) {dst.setPixel(x, y);}
 	}
 
 	void drawRect(const Scalar x, const Scalar y, const Scalar w, const Scalar h) {
-		drawLineHor(x,x+w, y);		// top
-		drawLineHor(x,x+w, y+h);	// bottom
-		drawLineVer(y,y+h, x);		// left
-		drawLineVer(y,y+h, x+w);	// right
+		drawLineHor(x, x+w-1, y);		// top
+		drawLineHor(x, x+w-1, y+h-1);	// bottom
+		drawLineVer(y+1, y+h-2, x);		// left		2 pixels already included above
+		drawLineVer(y+1, y+h-2, x+w-1);	// right	2 pixels already included above
 	}
 
 //	void drawRect(const Scalar x1, const Scalar y1, const Scalar x2, const Scalar y2) {
diff --git a/ext/sens/INA219.h b/ext/sens/INA219.h
new file mode 100644
index 0000000..3a30adb
--- /dev/null
+++ b/ext/sens/INA219.h
@@ -0,0 +1,98 @@
+#ifndef SENS_INA_219
+#define SENS_INA_219
+
+/** 1-Channel i2c volt/ampere sensor */
+template <typename I2C> class INA219 {
+	
+private:
+
+	I2C& i2c;
+	static constexpr const uint8_t ADDR = 0b1000000;
+	static constexpr const char* NAME = "INA219";
+	
+	static constexpr const uint8_t REG_CFG = 0x00;
+	
+	static constexpr const uint8_t REG_VS = 0x01;	// shunt voltage
+	static constexpr const uint8_t REG_VB = 0x02;	// bus voltage
+	
+public:
+
+	struct Voltages {
+		
+		int		vShunt;	// in uV * 10(!!!)
+		int16_t	vBus;	// in mV
+		
+		int getMilliAmps(int shunt_milliOhm) const {
+			return (vShunt * 10) / shunt_milliOhm;
+		}
+		
+	};
+
+public:
+
+	INA219(I2C& i2c) : i2c(i2c) {
+		
+	}
+	
+	/** get the current config */
+	uint16_t getConfig() {
+		uint8_t buf[2];
+		i2c.readReg(ADDR, REG_CFG, 2, (uint8_t*)&buf); 
+		return getU16(buf);
+	}
+	
+	/** read both voltages (shunt and bus) */
+	Voltages getVoltages() {
+		
+		uint8_t buf[2];
+		Voltages res;
+		
+		i2c.readReg(ADDR, REG_VS, sizeof(buf), buf);
+		res.vShunt =	getShuntVoltage(buf);
+		i2c.readReg(ADDR, REG_VB, sizeof(buf), buf);
+		res.vBus =		getBusVoltage(buf);
+		
+		return res;
+	}
+	
+	/** is an INA219 present on the bus? */
+	bool isPresent() {
+		return i2c.query(ADDR);
+	}
+	
+	void dumpConfig() {
+		const uint16_t cfg = getConfig();
+		const uint8_t mode =	(cfg & 0b00000000000111) >> 0;
+		const uint8_t sadc =	(cfg & 0b00000001111000) >> 3;
+		const uint8_t badc =	(cfg & 0b00011110000000) >> 7;
+		const uint8_t pg =		(cfg & 0b01100000000000) >> 11;
+		const uint8_t brng =	(cfg & 0b10000000000000) >> 13;
+		printf("INA219\n");
+		printf("- Mode: %d", mode);
+		printf("- SADC: %d", sadc);
+		printf("- BADC: %d", badc);
+		printf("PG (shunt divider) %d", (1<<pg));
+		if (brng)	{printf("- bus voltage range [0:16]");}
+		else		{printf("- bus voltage range [0:32]");}		
+	}
+	
+private:
+
+	/** convert to bytes into a mV reading */
+	int16_t getBusVoltage(const uint8_t* buf) {
+		return (getU16(buf) >> 3) * 4;				// lower 3 bits are status indicators -> remove, the LSB equals 4 mV -> * 4
+	}
+	
+	/** convert to bytes into a uV reading */
+	int getShuntVoltage(const uint8_t* buf) {
+		return ((int)((int16_t)getU16(buf)));		// NOTE: LSB = 10 uV
+	}
+	
+	uint16_t getU16(const uint8_t* buf) {
+		return ((buf[0] << 8) | (buf[1] << 0));
+	}
+	
+};
+
+
+#endif // SENS_INA_219