diff --git a/circuit/mainboard/mainboard-cache.lib b/circuit/mainboard/mainboard-cache.lib
new file mode 100644
index 0000000..0132137
--- /dev/null
+++ b/circuit/mainboard/mainboard-cache.lib
@@ -0,0 +1,281 @@
+EESchema-LIBRARY Version 2.4
+#encoding utf-8
+#
+# 74xx_74HC245
+#
+DEF 74xx_74HC245 U 0 40 Y Y 1 L N
+F0 "U" -300 650 50 H V C CNN
+F1 "74xx_74HC245" -300 -650 50 H V C CNN
+F2 "" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+ALIAS 74HC245
+$FPLIST
+ DIP?20*
+$ENDFPLIST
+DRAW
+S -300 600 300 -600 1 1 10 f
+P 3 1 0 0 -25 -50 -25 50 25 50 N
+P 4 1 0 0 -50 -50 25 -50 25 50 50 50 N
+X A->B 1 -500 -400 200 R 50 50 1 0 I
+X GND 10 0 -800 200 U 50 50 1 0 W
+X B7 11 500 -200 200 L 50 50 1 0 T
+X B6 12 500 -100 200 L 50 50 1 0 T
+X B5 13 500 0 200 L 50 50 1 0 T
+X B4 14 500 100 200 L 50 50 1 0 T
+X B3 15 500 200 200 L 50 50 1 0 T
+X B2 16 500 300 200 L 50 50 1 0 T
+X B1 17 500 400 200 L 50 50 1 0 T
+X B0 18 500 500 200 L 50 50 1 0 T
+X CE 19 -500 -500 200 R 50 50 1 0 I I
+X A0 2 -500 500 200 R 50 50 1 0 T
+X VCC 20 0 800 200 D 50 50 1 0 W
+X A1 3 -500 400 200 R 50 50 1 0 T
+X A2 4 -500 300 200 R 50 50 1 0 T
+X A3 5 -500 200 200 R 50 50 1 0 T
+X A4 6 -500 100 200 R 50 50 1 0 T
+X A5 7 -500 0 200 R 50 50 1 0 T
+X A6 8 -500 -100 200 R 50 50 1 0 T
+X A7 9 -500 -200 200 R 50 50 1 0 T
+ENDDRAW
+ENDDEF
+#
+# 74xx_74LS138
+#
+DEF 74xx_74LS138 U 0 40 Y Y 1 L N
+F0 "U" -300 450 50 H V C CNN
+F1 "74xx_74LS138" -300 -550 50 H V C CNN
+F2 "" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+$FPLIST
+ DIP?16*
+$ENDFPLIST
+DRAW
+S -300 400 300 -500 1 1 10 f
+X A0 1 -500 300 200 R 50 50 1 0 I
+X O5 10 500 -200 200 L 50 50 1 0 O V
+X O4 11 500 -100 200 L 50 50 1 0 O V
+X O3 12 500 0 200 L 50 50 1 0 O V
+X O2 13 500 100 200 L 50 50 1 0 O V
+X O1 14 500 200 200 L 50 50 1 0 O V
+X O0 15 500 300 200 L 50 50 1 0 O V
+X VCC 16 0 600 200 D 50 50 1 0 W
+X A1 2 -500 200 200 R 50 50 1 0 I
+X A2 3 -500 100 200 R 50 50 1 0 I
+X E1 4 -500 -400 200 R 50 50 1 0 I L
+X E2 5 -500 -300 200 R 50 50 1 0 I L
+X E3 6 -500 -200 200 R 50 50 1 0 I
+X O7 7 500 -400 200 L 50 50 1 0 O V
+X GND 8 0 -700 200 U 50 50 1 0 W
+X O6 9 500 -300 200 L 50 50 1 0 O V
+ENDDRAW
+ENDDEF
+#
+# Analog_Switch_CD4051B
+#
+DEF Analog_Switch_CD4051B U 0 20 Y Y 1 F N
+F0 "U" -400 650 50 H V L CNN
+F1 "Analog_Switch_CD4051B" 150 650 50 H V L CNN
+F2 "" 150 -750 50 H I L CNN
+F3 "" -20 100 50 H I C CNN
+$FPLIST
+ TSSOP*4.4x5mm*P0.65mm*
+ DIP*W7.62*
+ SOIC*3.9x9.9mm*P1.27mm*
+ SO*5.3x10.2mm*P1.27mm*
+$ENDFPLIST
+DRAW
+C -240 100 20 0 1 10 N
+C -90 100 20 0 1 10 N
+C 140 -500 20 0 1 10 N
+C 140 -400 20 0 1 10 N
+C 140 -300 20 0 1 10 N
+C 140 -200 20 0 1 10 N
+C 140 -100 20 0 1 10 N
+C 140 0 20 0 1 10 N
+C 140 100 20 0 1 10 N
+C 140 200 20 0 1 10 N
+S -400 250 -200 550 0 1 10 N
+S -400 600 400 -600 0 1 10 f
+P 2 0 1 10 -320 100 -260 100 N
+P 2 0 1 10 -220 110 -130 140 N
+P 2 0 1 10 -180 0 -205 0 N
+P 2 0 1 10 -180 10 -180 35 N
+P 2 0 1 10 -180 60 -180 85 N
+P 2 0 1 10 -180 400 -200 400 N
+P 2 0 1 10 -150 400 -125 400 N
+P 2 0 1 10 -70 110 90 200 N
+P 2 0 1 10 -70 400 -90 400 N
+P 2 0 1 10 -20 150 -20 175 N
+P 2 0 1 10 -20 200 -20 225 N
+P 2 0 1 10 -20 250 -20 275 N
+P 2 0 1 10 -20 300 -20 325 N
+P 2 0 1 10 -20 340 -20 360 N
+P 2 0 1 10 -20 380 -20 400 N
+P 2 0 1 10 -20 400 -40 400 N
+P 2 0 1 10 160 -500 230 -500 N
+P 2 0 1 10 160 -400 230 -400 N
+P 2 0 1 10 160 -300 230 -300 N
+P 2 0 1 10 160 -200 230 -200 N
+P 2 0 1 10 160 -100 230 -100 N
+P 2 0 1 10 160 0 230 0 N
+P 2 0 1 10 160 100 230 100 N
+P 2 0 1 10 160 200 230 200 N
+X X4 1 500 -200 100 L 50 50 1 1 B
+X B 10 -500 400 100 R 50 50 1 1 I
+X A 11 -500 500 100 R 50 50 1 1 I
+X X3 12 500 -100 100 L 50 50 1 1 B
+X X0 13 500 200 100 L 50 50 1 1 B
+X X1 14 500 100 100 L 50 50 1 1 B
+X X2 15 500 0 100 L 50 50 1 1 B
+X VDD 16 100 700 100 D 50 50 1 1 W
+X X6 2 500 -400 100 L 50 50 1 1 B
+X X 3 -500 100 100 R 50 50 1 1 B
+X X7 4 500 -500 100 L 50 50 1 1 B
+X X5 5 500 -300 100 L 50 50 1 1 B
+X INH 6 -500 0 100 R 50 50 1 1 I
+X VEE 7 -100 -700 100 U 50 50 1 1 W
+X VSS 8 0 -700 100 U 50 50 1 1 W
+X C 9 -500 300 100 R 50 50 1 1 I
+ENDDRAW
+ENDDEF
+#
+# Connector_Raspberry_Pi_2_3
+#
+DEF Connector_Raspberry_Pi_2_3 J 0 40 Y Y 1 F N
+F0 "J" -700 1250 50 H V L BNN
+F1 "Connector_Raspberry_Pi_2_3" 400 -1250 50 H V L TNN
+F2 "" 0 0 50 H I C CNN
+F3 "" 0 0 50 H I C CNN
+$FPLIST
+ PinHeader*2x20*P2.54mm*Vertical*
+ PinSocket*2x20*P2.54mm*Vertical*
+$ENDFPLIST
+DRAW
+S -700 1200 700 -1200 0 1 10 f
+S -665 -690 -700 -710 1 1 0 N
+S -665 -590 -700 -610 1 1 0 N
+S -665 -490 -700 -510 1 1 0 N
+S -665 -390 -700 -410 1 1 0 N
+S -665 -290 -700 -310 1 1 0 N
+S -665 -190 -700 -210 1 1 0 N
+S -665 10 -700 -10 1 1 0 N
+S -665 110 -700 90 1 1 0 N
+S -665 210 -700 190 1 1 0 N
+S -665 410 -700 390 1 1 0 N
+S -665 510 -700 490 1 1 0 N
+S -665 610 -700 590 1 1 0 N
+S -665 810 -700 790 1 1 0 N
+S -665 910 -700 890 1 1 0 N
+S -410 -1165 -390 -1200 1 1 0 N
+S -310 -1165 -290 -1200 1 1 0 N
+S -210 -1165 -190 -1200 1 1 0 N
+S -210 1200 -190 1165 1 1 0 N
+S -110 -1165 -90 -1200 1 1 0 N
+S -110 1200 -90 1165 1 1 0 N
+S -10 -1165 10 -1200 1 1 0 N
+S 90 -1165 110 -1200 1 1 0 N
+S 90 1200 110 1165 1 1 0 N
+S 190 -1165 210 -1200 1 1 0 N
+S 190 1200 210 1165 1 1 0 N
+S 290 -1165 310 -1200 1 1 0 N
+S 700 -790 665 -810 1 1 0 N
+S 700 -690 665 -710 1 1 0 N
+S 700 -490 665 -510 1 1 0 N
+S 700 -390 665 -410 1 1 0 N
+S 700 -290 665 -310 1 1 0 N
+S 700 -190 665 -210 1 1 0 N
+S 700 -90 665 -110 1 1 0 N
+S 700 110 665 90 1 1 0 N
+S 700 210 665 190 1 1 0 N
+S 700 310 665 290 1 1 0 N
+S 700 510 665 490 1 1 0 N
+S 700 610 665 590 1 1 0 N
+S 700 810 665 790 1 1 0 N
+S 700 910 665 890 1 1 0 N
+X 3V3 1 100 1300 100 D 50 50 1 1 W
+X GPIO15/RXD 10 -800 800 100 R 50 50 1 1 B
+X GPIO17 11 -800 500 100 R 50 50 1 1 B
+X GPIO18/PWM0 12 -800 400 100 R 50 50 1 1 B
+X GPIO27 13 -800 -700 100 R 50 50 1 1 B
+X GND 14 -200 -1300 100 U 50 50 1 1 W
+X GPIO22 15 -800 -200 100 R 50 50 1 1 B
+X GPIO23 16 -800 -300 100 R 50 50 1 1 B
+X 3V3 17 200 1300 100 D 50 50 1 1 W
+X GPIO24 18 -800 -400 100 R 50 50 1 1 B
+X MOSI0/GPIO10 19 800 -400 100 L 50 50 1 1 B
+X 5V 2 -200 1300 100 D 50 50 1 1 W
+X GND 20 -100 -1300 100 U 50 50 1 1 W
+X MISO0/GPIO9 21 800 -300 100 L 50 50 1 1 B
+X GPIO25 22 -800 -500 100 R 50 50 1 1 B
+X SCLK0/GPIO11 23 800 -500 100 L 50 50 1 1 B
+X ~CE0~/GPIO8 24 800 -200 100 L 50 50 1 1 B
+X GND 25 0 -1300 100 U 50 50 1 1 W
+X ~CE1~/GPIO7 26 800 -100 100 L 50 50 1 1 B
+X ID_SD/GPIO0 27 800 900 100 L 50 50 1 1 B
+X ID_SC/GPIO1 28 800 800 100 L 50 50 1 1 B
+X GCLK1/GPIO5 29 800 200 100 L 50 50 1 1 B
+X SDA/GPIO2 3 800 600 100 L 50 50 1 1 B
+X GND 30 100 -1300 100 U 50 50 1 1 W
+X GCLK2/GPIO6 31 800 100 100 L 50 50 1 1 B
+X PWM0/GPIO12 32 800 -700 100 L 50 50 1 1 B
+X PWM1/GPIO13 33 800 -800 100 L 50 50 1 1 B
+X GND 34 200 -1300 100 U 50 50 1 1 W
+X GPIO19/MISO1 35 -800 200 100 R 50 50 1 1 B
+X GPIO16 36 -800 600 100 R 50 50 1 1 B
+X GPIO26 37 -800 -600 100 R 50 50 1 1 B
+X GPIO20/MOSI1 38 -800 100 100 R 50 50 1 1 B
+X GND 39 300 -1300 100 U 50 50 1 1 W
+X 5V 4 -100 1300 100 D 50 50 1 1 W
+X GPIO21/SCLK1 40 -800 0 100 R 50 50 1 1 B
+X SCL/GPIO3 5 800 500 100 L 50 50 1 1 B
+X GND 6 -400 -1300 100 U 50 50 1 1 W
+X GCLK0/GPIO4 7 800 300 100 L 50 50 1 1 B
+X GPIO14/TXD 8 -800 900 100 R 50 50 1 1 B
+X GND 9 -300 -1300 100 U 50 50 1 1 W
+ENDDRAW
+ENDDEF
+#
+# Interface_Expansion_MCP23017_SP
+#
+DEF Interface_Expansion_MCP23017_SP U 0 40 Y Y 1 F N
+F0 "U" -450 950 50 H V C CNN
+F1 "Interface_Expansion_MCP23017_SP" 0 0 50 H V C CNN
+F2 "Package_DIP:DIP-28_W7.62mm" 200 -1000 50 H I L CNN
+F3 "" 200 -1100 50 H I L CNN
+$FPLIST
+ DIP*W7.62mm*
+$ENDFPLIST
+DRAW
+S -500 900 500 -900 0 1 10 f
+X GPB0 1 700 800 200 L 50 50 1 1 B
+X VSS 10 0 -1100 200 U 50 50 1 1 W
+X NC 11 -500 600 200 R 50 50 1 1 N N
+X SCK 12 -700 700 200 R 50 50 1 1 I
+X SDA 13 -700 800 200 R 50 50 1 1 B
+X NC 14 -500 500 200 R 50 50 1 1 N N
+X A0 15 -700 -800 200 R 50 50 1 1 I
+X A1 16 -700 -700 200 R 50 50 1 1 I
+X A2 17 -700 -600 200 R 50 50 1 1 I
+X ~RESET~ 18 -700 -100 200 R 50 50 1 1 I
+X INTB 19 -700 200 200 R 50 50 1 1 T
+X GPB1 2 700 700 200 L 50 50 1 1 B
+X INTA 20 -700 100 200 R 50 50 1 1 T
+X GPA0 21 700 -100 200 L 50 50 1 1 B
+X GPA1 22 700 -200 200 L 50 50 1 1 B
+X GPA2 23 700 -300 200 L 50 50 1 1 B
+X GPA3 24 700 -400 200 L 50 50 1 1 B
+X GPA4 25 700 -500 200 L 50 50 1 1 B
+X GPA5 26 700 -600 200 L 50 50 1 1 B
+X GPA6 27 700 -700 200 L 50 50 1 1 B
+X GPA7 28 700 -800 200 L 50 50 1 1 B
+X GPB2 3 700 600 200 L 50 50 1 1 B
+X GPB3 4 700 500 200 L 50 50 1 1 B
+X GPB4 5 700 400 200 L 50 50 1 1 B
+X GPB5 6 700 300 200 L 50 50 1 1 B
+X GPB6 7 700 200 200 L 50 50 1 1 B
+X GPB7 8 700 100 200 L 50 50 1 1 B
+X VDD 9 0 1100 200 D 50 50 1 1 W
+ENDDRAW
+ENDDEF
+#
+#End Library
diff --git a/circuit/mainboard/mainboard.bak b/circuit/mainboard/mainboard.bak
new file mode 100644
index 0000000..44e92e7
--- /dev/null
+++ b/circuit/mainboard/mainboard.bak
@@ -0,0 +1,71 @@
+EESchema Schematic File Version 4
+EELAYER 26 0
+EELAYER END
+$Descr A4 11693 8268
+encoding utf-8
+Sheet 1 1
+Title ""
+Date ""
+Rev ""
+Comp ""
+Comment1 ""
+Comment2 ""
+Comment3 ""
+Comment4 ""
+$EndDescr
+$Comp
+L Connector:Raspberry_Pi_2_3 J1
+U 1 1 5C35F1BF
+P 2500 2300
+F 0 "J1" H 2500 3778 50  0000 C CNN
+F 1 "Raspberry_Pi_2_3" H 2500 3687 50  0000 C CNN
+F 2 "Connector_PinHeader_2.54mm:PinHeader_2x20_P2.54mm_Vertical" H 2500 2300 50  0001 C CNN
+F 3 "https://www.raspberrypi.org/documentation/hardware/raspberrypi/schematics/rpi_SCH_3bplus_1p0_reduced.pdf" H 2500 2300 50  0001 C CNN
+	1    2500 2300
+	1    0    0    -1  
+$EndComp
+$Comp
+L 74xx:74HC245 U1
+U 1 1 5C35F2D7
+P 1950 5850
+F 0 "U1" H 1950 6828 50  0000 C CNN
+F 1 "74HC245" H 1950 6737 50  0000 C CNN
+F 2 "" H 1950 5850 50  0001 C CNN
+F 3 "http://www.ti.com/lit/gpn/sn74HC245" H 1950 5850 50  0001 C CNN
+	1    1950 5850
+	1    0    0    -1  
+$EndComp
+$Comp
+L Analog_Switch:CD4051B U2
+U 1 1 5C35F42C
+P 4850 4600
+F 0 "U2" H 4850 5478 50  0000 C CNN
+F 1 "CD4051B" H 4850 5387 50  0000 C CNN
+F 2 "" H 5000 3850 50  0001 L CNN
+F 3 "http://www.ti.com/lit/ds/symlink/cd4052b.pdf" H 4830 4700 50  0001 C CNN
+	1    4850 4600
+	1    0    0    -1  
+$EndComp
+$Comp
+L Interface_Expansion:MCP23017_SP U4
+U 1 1 5C35F617
+P 4800 2150
+F 0 "U4" H 4800 3428 50  0000 C CNN
+F 1 "MCP23017_SP" H 4800 3337 50  0000 C CNN
+F 2 "Package_DIP:DIP-28_W7.62mm" H 5000 1150 50  0001 L CNN
+F 3 "http://ww1.microchip.com/downloads/en/DeviceDoc/20001952C.pdf" H 5000 1050 50  0001 L CNN
+	1    4800 2150
+	1    0    0    -1  
+$EndComp
+$Comp
+L 74xx:74LS138 U3
+U 1 1 5C35F892
+P 7800 1350
+F 0 "U3" H 7800 2128 50  0000 C CNN
+F 1 "74LS138" H 7800 2037 50  0000 C CNN
+F 2 "" H 7800 1350 50  0001 C CNN
+F 3 "http://www.ti.com/lit/gpn/sn74LS138" H 7800 1350 50  0001 C CNN
+	1    7800 1350
+	1    0    0    -1  
+$EndComp
+$EndSCHEMATC
diff --git a/circuit/mainboard/mainboard.kicad_pcb b/circuit/mainboard/mainboard.kicad_pcb
new file mode 100644
index 0000000..02c8ecb
--- /dev/null
+++ b/circuit/mainboard/mainboard.kicad_pcb
@@ -0,0 +1 @@
+(kicad_pcb (version 4) (host kicad "dummy file") )
diff --git a/circuit/mainboard/mainboard.net b/circuit/mainboard/mainboard.net
new file mode 100644
index 0000000..63459a4
--- /dev/null
+++ b/circuit/mainboard/mainboard.net
@@ -0,0 +1,468 @@
+(export (version D)
+  (design
+    (source /home/johannes/git/flippr-circuit/circuit/mainboard/mainboard.sch)
+    (date "Mi 09 Jan 2019 15:04:16 CET")
+    (tool "Eeschema 5.0.2-bee76a0~70~ubuntu18.04.1")
+    (sheet (number 1) (name /) (tstamps /)
+      (title_block
+        (title)
+        (company)
+        (rev)
+        (date)
+        (source mainboard.sch)
+        (comment (number 1) (value ""))
+        (comment (number 2) (value ""))
+        (comment (number 3) (value ""))
+        (comment (number 4) (value "")))))
+  (components
+    (comp (ref J1)
+      (value Raspberry_Pi_2_3)
+      (footprint Connector_PinHeader_2.54mm:PinHeader_2x20_P2.54mm_Vertical)
+      (datasheet https://www.raspberrypi.org/documentation/hardware/raspberrypi/schematics/rpi_SCH_3bplus_1p0_reduced.pdf)
+      (libsource (lib Connector) (part Raspberry_Pi_2_3) (description "expansion header for Raspberry Pi 2 & 3"))
+      (sheetpath (names /) (tstamps /))
+      (tstamp 5C35F1BF))
+    (comp (ref U1)
+      (value 74HC245)
+      (datasheet http://www.ti.com/lit/gpn/sn74HC245)
+      (libsource (lib 74xx) (part 74HC245) (description "Octal BUS Transceivers, 3-State outputs"))
+      (sheetpath (names /) (tstamps /))
+      (tstamp 5C35F2D7))
+    (comp (ref U2)
+      (value CD4051B)
+      (datasheet http://www.ti.com/lit/ds/symlink/cd4052b.pdf)
+      (libsource (lib Analog_Switch) (part CD4051B) (description "CMOS single 8-channel analog multiplexer demultiplexer, TSSOP-16/DIP-16/SOIC-16"))
+      (sheetpath (names /) (tstamps /))
+      (tstamp 5C35F42C))
+    (comp (ref U4)
+      (value MCP23017_SP)
+      (footprint Package_DIP:DIP-28_W7.62mm)
+      (datasheet http://ww1.microchip.com/downloads/en/DeviceDoc/20001952C.pdf)
+      (libsource (lib Interface_Expansion) (part MCP23017_SP) (description "16-bit I/O expander, I2C, interrupts, w pull-ups, SPDIP-28"))
+      (sheetpath (names /) (tstamps /))
+      (tstamp 5C35F617))
+    (comp (ref U3)
+      (value 74LS138)
+      (datasheet http://www.ti.com/lit/gpn/sn74LS138)
+      (libsource (lib 74xx) (part 74LS138) (description "Decoder 3 to 8 active low outputs"))
+      (sheetpath (names /) (tstamps /))
+      (tstamp 5C35F892)))
+  (libparts
+    (libpart (lib 74xx) (part 74LS138)
+      (description "Decoder 3 to 8 active low outputs")
+      (docs http://www.ti.com/lit/gpn/sn74LS138)
+      (footprints
+        (fp DIP?16*))
+      (fields
+        (field (name Reference) U)
+        (field (name Value) 74LS138))
+      (pins
+        (pin (num 1) (name A0) (type input))
+        (pin (num 2) (name A1) (type input))
+        (pin (num 3) (name A2) (type input))
+        (pin (num 4) (name E1) (type input))
+        (pin (num 5) (name E2) (type input))
+        (pin (num 6) (name E3) (type input))
+        (pin (num 7) (name O7) (type output))
+        (pin (num 8) (name GND) (type power_in))
+        (pin (num 9) (name O6) (type output))
+        (pin (num 10) (name O5) (type output))
+        (pin (num 11) (name O4) (type output))
+        (pin (num 12) (name O3) (type output))
+        (pin (num 13) (name O2) (type output))
+        (pin (num 14) (name O1) (type output))
+        (pin (num 15) (name O0) (type output))
+        (pin (num 16) (name VCC) (type power_in))))
+    (libpart (lib 74xx) (part 74LS245)
+      (aliases
+        (alias 74HC245))
+      (description "Octal BUS Transceivers, 3-State outputs")
+      (docs http://www.ti.com/lit/gpn/sn74LS245)
+      (footprints
+        (fp DIP?20*))
+      (fields
+        (field (name Reference) U)
+        (field (name Value) 74LS245))
+      (pins
+        (pin (num 1) (name A->B) (type input))
+        (pin (num 2) (name A0) (type 3state))
+        (pin (num 3) (name A1) (type 3state))
+        (pin (num 4) (name A2) (type 3state))
+        (pin (num 5) (name A3) (type 3state))
+        (pin (num 6) (name A4) (type 3state))
+        (pin (num 7) (name A5) (type 3state))
+        (pin (num 8) (name A6) (type 3state))
+        (pin (num 9) (name A7) (type 3state))
+        (pin (num 10) (name GND) (type power_in))
+        (pin (num 11) (name B7) (type 3state))
+        (pin (num 12) (name B6) (type 3state))
+        (pin (num 13) (name B5) (type 3state))
+        (pin (num 14) (name B4) (type 3state))
+        (pin (num 15) (name B3) (type 3state))
+        (pin (num 16) (name B2) (type 3state))
+        (pin (num 17) (name B1) (type 3state))
+        (pin (num 18) (name B0) (type 3state))
+        (pin (num 19) (name CE) (type input))
+        (pin (num 20) (name VCC) (type power_in))))
+    (libpart (lib Analog_Switch) (part CD4051B)
+      (description "CMOS single 8-channel analog multiplexer demultiplexer, TSSOP-16/DIP-16/SOIC-16")
+      (docs http://www.ti.com/lit/ds/symlink/cd4052b.pdf)
+      (footprints
+        (fp TSSOP*4.4x5mm*P0.65mm*)
+        (fp DIP*W7.62*)
+        (fp SOIC*3.9x9.9mm*P1.27mm*)
+        (fp SO*5.3x10.2mm*P1.27mm*))
+      (fields
+        (field (name Reference) U)
+        (field (name Value) CD4051B))
+      (pins
+        (pin (num 1) (name X4) (type BiDi))
+        (pin (num 2) (name X6) (type BiDi))
+        (pin (num 3) (name X) (type BiDi))
+        (pin (num 4) (name X7) (type BiDi))
+        (pin (num 5) (name X5) (type BiDi))
+        (pin (num 6) (name INH) (type input))
+        (pin (num 7) (name VEE) (type power_in))
+        (pin (num 8) (name VSS) (type power_in))
+        (pin (num 9) (name C) (type input))
+        (pin (num 10) (name B) (type input))
+        (pin (num 11) (name A) (type input))
+        (pin (num 12) (name X3) (type BiDi))
+        (pin (num 13) (name X0) (type BiDi))
+        (pin (num 14) (name X1) (type BiDi))
+        (pin (num 15) (name X2) (type BiDi))
+        (pin (num 16) (name VDD) (type power_in))))
+    (libpart (lib Connector) (part Raspberry_Pi_2_3)
+      (description "expansion header for Raspberry Pi 2 & 3")
+      (docs https://www.raspberrypi.org/documentation/hardware/raspberrypi/schematics/rpi_SCH_3bplus_1p0_reduced.pdf)
+      (footprints
+        (fp PinHeader*2x20*P2.54mm*Vertical*)
+        (fp PinSocket*2x20*P2.54mm*Vertical*))
+      (fields
+        (field (name Reference) J)
+        (field (name Value) Raspberry_Pi_2_3))
+      (pins
+        (pin (num 1) (name 3V3) (type power_in))
+        (pin (num 2) (name 5V) (type power_in))
+        (pin (num 3) (name SDA/GPIO2) (type BiDi))
+        (pin (num 4) (name 5V) (type power_in))
+        (pin (num 5) (name SCL/GPIO3) (type BiDi))
+        (pin (num 6) (name GND) (type power_in))
+        (pin (num 7) (name GCLK0/GPIO4) (type BiDi))
+        (pin (num 8) (name GPIO14/TXD) (type BiDi))
+        (pin (num 9) (name GND) (type power_in))
+        (pin (num 10) (name GPIO15/RXD) (type BiDi))
+        (pin (num 11) (name GPIO17) (type BiDi))
+        (pin (num 12) (name GPIO18/PWM0) (type BiDi))
+        (pin (num 13) (name GPIO27) (type BiDi))
+        (pin (num 14) (name GND) (type power_in))
+        (pin (num 15) (name GPIO22) (type BiDi))
+        (pin (num 16) (name GPIO23) (type BiDi))
+        (pin (num 17) (name 3V3) (type power_in))
+        (pin (num 18) (name GPIO24) (type BiDi))
+        (pin (num 19) (name MOSI0/GPIO10) (type BiDi))
+        (pin (num 20) (name GND) (type power_in))
+        (pin (num 21) (name MISO0/GPIO9) (type BiDi))
+        (pin (num 22) (name GPIO25) (type BiDi))
+        (pin (num 23) (name SCLK0/GPIO11) (type BiDi))
+        (pin (num 24) (name ~CE0~/GPIO8) (type BiDi))
+        (pin (num 25) (name GND) (type power_in))
+        (pin (num 26) (name ~CE1~/GPIO7) (type BiDi))
+        (pin (num 27) (name ID_SD/GPIO0) (type BiDi))
+        (pin (num 28) (name ID_SC/GPIO1) (type BiDi))
+        (pin (num 29) (name GCLK1/GPIO5) (type BiDi))
+        (pin (num 30) (name GND) (type power_in))
+        (pin (num 31) (name GCLK2/GPIO6) (type BiDi))
+        (pin (num 32) (name PWM0/GPIO12) (type BiDi))
+        (pin (num 33) (name PWM1/GPIO13) (type BiDi))
+        (pin (num 34) (name GND) (type power_in))
+        (pin (num 35) (name GPIO19/MISO1) (type BiDi))
+        (pin (num 36) (name GPIO16) (type BiDi))
+        (pin (num 37) (name GPIO26) (type BiDi))
+        (pin (num 38) (name GPIO20/MOSI1) (type BiDi))
+        (pin (num 39) (name GND) (type power_in))
+        (pin (num 40) (name GPIO21/SCLK1) (type BiDi))))
+    (libpart (lib Interface_Expansion) (part MCP23017_SP)
+      (description "16-bit I/O expander, I2C, interrupts, w pull-ups, SPDIP-28")
+      (docs http://ww1.microchip.com/downloads/en/DeviceDoc/20001952C.pdf)
+      (footprints
+        (fp DIP*W7.62mm*))
+      (fields
+        (field (name Reference) U)
+        (field (name Value) MCP23017_SP)
+        (field (name Footprint) Package_DIP:DIP-28_W7.62mm))
+      (pins
+        (pin (num 1) (name GPB0) (type BiDi))
+        (pin (num 2) (name GPB1) (type BiDi))
+        (pin (num 3) (name GPB2) (type BiDi))
+        (pin (num 4) (name GPB3) (type BiDi))
+        (pin (num 5) (name GPB4) (type BiDi))
+        (pin (num 6) (name GPB5) (type BiDi))
+        (pin (num 7) (name GPB6) (type BiDi))
+        (pin (num 8) (name GPB7) (type BiDi))
+        (pin (num 9) (name VDD) (type power_in))
+        (pin (num 10) (name VSS) (type power_in))
+        (pin (num 11) (name NC) (type NotConnected))
+        (pin (num 12) (name SCK) (type input))
+        (pin (num 13) (name SDA) (type BiDi))
+        (pin (num 14) (name NC) (type NotConnected))
+        (pin (num 15) (name A0) (type input))
+        (pin (num 16) (name A1) (type input))
+        (pin (num 17) (name A2) (type input))
+        (pin (num 18) (name ~RESET~) (type input))
+        (pin (num 19) (name INTB) (type 3state))
+        (pin (num 20) (name INTA) (type 3state))
+        (pin (num 21) (name GPA0) (type BiDi))
+        (pin (num 22) (name GPA1) (type BiDi))
+        (pin (num 23) (name GPA2) (type BiDi))
+        (pin (num 24) (name GPA3) (type BiDi))
+        (pin (num 25) (name GPA4) (type BiDi))
+        (pin (num 26) (name GPA5) (type BiDi))
+        (pin (num 27) (name GPA6) (type BiDi))
+        (pin (num 28) (name GPA7) (type BiDi)))))
+  (libraries
+    (library (logical 74xx)
+      (uri /usr/share/kicad/library/74xx.lib))
+    (library (logical Analog_Switch)
+      (uri /usr/share/kicad/library/Analog_Switch.lib))
+    (library (logical Connector)
+      (uri /usr/share/kicad/library/Connector.lib))
+    (library (logical Interface_Expansion)
+      (uri /usr/share/kicad/library/Interface_Expansion.lib)))
+  (nets
+    (net (code 1) (name "Net-(J1-Pad26)")
+      (node (ref J1) (pin 26))
+      (node (ref U4) (pin 21)))
+    (net (code 2) (name "Net-(U4-Pad22)")
+      (node (ref U4) (pin 22)))
+    (net (code 3) (name "Net-(U4-Pad23)")
+      (node (ref U4) (pin 23)))
+    (net (code 4) (name "Net-(U4-Pad24)")
+      (node (ref U4) (pin 24)))
+    (net (code 5) (name "Net-(U4-Pad25)")
+      (node (ref U4) (pin 25)))
+    (net (code 6) (name "Net-(U4-Pad26)")
+      (node (ref U4) (pin 26)))
+    (net (code 7) (name "Net-(U4-Pad27)")
+      (node (ref U4) (pin 27)))
+    (net (code 8) (name "Net-(U4-Pad2)")
+      (node (ref U4) (pin 2)))
+    (net (code 9) (name "Net-(U4-Pad3)")
+      (node (ref U4) (pin 3)))
+    (net (code 10) (name "Net-(U4-Pad4)")
+      (node (ref U4) (pin 4)))
+    (net (code 11) (name "Net-(U4-Pad5)")
+      (node (ref U4) (pin 5)))
+    (net (code 12) (name "Net-(U4-Pad6)")
+      (node (ref U4) (pin 6)))
+    (net (code 13) (name "Net-(U4-Pad7)")
+      (node (ref U4) (pin 7)))
+    (net (code 14) (name "Net-(U4-Pad8)")
+      (node (ref U4) (pin 8)))
+    (net (code 15) (name "Net-(U4-Pad9)")
+      (node (ref U4) (pin 9)))
+    (net (code 16) (name "Net-(U3-Pad1)")
+      (node (ref U3) (pin 1)))
+    (net (code 17) (name "Net-(U4-Pad12)")
+      (node (ref U4) (pin 12)))
+    (net (code 18) (name "Net-(U2-Pad5)")
+      (node (ref U2) (pin 5)))
+    (net (code 19) (name "Net-(U2-Pad6)")
+      (node (ref U2) (pin 6)))
+    (net (code 20) (name "Net-(U2-Pad7)")
+      (node (ref U2) (pin 7)))
+    (net (code 21) (name "Net-(U2-Pad8)")
+      (node (ref U2) (pin 8)))
+    (net (code 22) (name "Net-(U2-Pad9)")
+      (node (ref U2) (pin 9)))
+    (net (code 23) (name "Net-(U4-Pad1)")
+      (node (ref U4) (pin 1)))
+    (net (code 24) (name "Net-(U4-Pad10)")
+      (node (ref U4) (pin 10)))
+    (net (code 25) (name "Net-(U4-Pad11)")
+      (node (ref U4) (pin 11)))
+    (net (code 26) (name "Net-(U3-Pad10)")
+      (node (ref U3) (pin 10)))
+    (net (code 27) (name "Net-(U4-Pad14)")
+      (node (ref U4) (pin 14)))
+    (net (code 28) (name "Net-(U4-Pad15)")
+      (node (ref U4) (pin 15)))
+    (net (code 29) (name "Net-(U4-Pad16)")
+      (node (ref U4) (pin 16)))
+    (net (code 30) (name "Net-(U4-Pad17)")
+      (node (ref U4) (pin 17)))
+    (net (code 31) (name "Net-(U4-Pad18)")
+      (node (ref U4) (pin 18)))
+    (net (code 32) (name "Net-(U4-Pad19)")
+      (node (ref U4) (pin 19)))
+    (net (code 33) (name "Net-(J1-Pad1)")
+      (node (ref U4) (pin 13))
+      (node (ref J1) (pin 1)))
+    (net (code 34) (name "Net-(J1-Pad2)")
+      (node (ref U4) (pin 20))
+      (node (ref J1) (pin 2)))
+    (net (code 35) (name "Net-(J1-Pad40)")
+      (node (ref J1) (pin 40))
+      (node (ref U4) (pin 28)))
+    (net (code 36) (name "Net-(U3-Pad4)")
+      (node (ref U3) (pin 4)))
+    (net (code 37) (name "Net-(U3-Pad11)")
+      (node (ref U3) (pin 11)))
+    (net (code 38) (name "Net-(U3-Pad12)")
+      (node (ref U3) (pin 12)))
+    (net (code 39) (name "Net-(U3-Pad13)")
+      (node (ref U3) (pin 13)))
+    (net (code 40) (name "Net-(U3-Pad14)")
+      (node (ref U3) (pin 14)))
+    (net (code 41) (name "Net-(U3-Pad15)")
+      (node (ref U3) (pin 15)))
+    (net (code 42) (name "Net-(U3-Pad16)")
+      (node (ref U3) (pin 16)))
+    (net (code 43) (name "Net-(U3-Pad2)")
+      (node (ref U3) (pin 2)))
+    (net (code 44) (name "Net-(U3-Pad3)")
+      (node (ref U3) (pin 3)))
+    (net (code 45) (name "Net-(U2-Pad4)")
+      (node (ref U2) (pin 4)))
+    (net (code 46) (name "Net-(U3-Pad5)")
+      (node (ref U3) (pin 5)))
+    (net (code 47) (name "Net-(U3-Pad6)")
+      (node (ref U3) (pin 6)))
+    (net (code 48) (name "Net-(U3-Pad7)")
+      (node (ref U3) (pin 7)))
+    (net (code 49) (name "Net-(U3-Pad8)")
+      (node (ref U3) (pin 8)))
+    (net (code 50) (name "Net-(U3-Pad9)")
+      (node (ref U3) (pin 9)))
+    (net (code 51) (name "Net-(J1-Pad33)")
+      (node (ref J1) (pin 33)))
+    (net (code 52) (name "Net-(J1-Pad27)")
+      (node (ref J1) (pin 27)))
+    (net (code 53) (name "Net-(J1-Pad28)")
+      (node (ref J1) (pin 28)))
+    (net (code 54) (name "Net-(J1-Pad29)")
+      (node (ref J1) (pin 29)))
+    (net (code 55) (name "Net-(J1-Pad3)")
+      (node (ref J1) (pin 3)))
+    (net (code 56) (name "Net-(J1-Pad30)")
+      (node (ref J1) (pin 30)))
+    (net (code 57) (name "Net-(J1-Pad31)")
+      (node (ref J1) (pin 31)))
+    (net (code 58) (name "Net-(J1-Pad32)")
+      (node (ref J1) (pin 32)))
+    (net (code 59) (name "Net-(J1-Pad25)")
+      (node (ref J1) (pin 25)))
+    (net (code 60) (name "Net-(J1-Pad34)")
+      (node (ref J1) (pin 34)))
+    (net (code 61) (name "Net-(J1-Pad35)")
+      (node (ref J1) (pin 35)))
+    (net (code 62) (name "Net-(J1-Pad36)")
+      (node (ref J1) (pin 36)))
+    (net (code 63) (name "Net-(J1-Pad37)")
+      (node (ref J1) (pin 37)))
+    (net (code 64) (name "Net-(J1-Pad38)")
+      (node (ref J1) (pin 38)))
+    (net (code 65) (name "Net-(J1-Pad39)")
+      (node (ref J1) (pin 39)))
+    (net (code 66) (name "Net-(J1-Pad4)")
+      (node (ref J1) (pin 4)))
+    (net (code 67) (name "Net-(J1-Pad18)")
+      (node (ref J1) (pin 18)))
+    (net (code 68) (name "Net-(J1-Pad10)")
+      (node (ref J1) (pin 10)))
+    (net (code 69) (name "Net-(J1-Pad11)")
+      (node (ref J1) (pin 11)))
+    (net (code 70) (name "Net-(J1-Pad12)")
+      (node (ref J1) (pin 12)))
+    (net (code 71) (name "Net-(J1-Pad13)")
+      (node (ref J1) (pin 13)))
+    (net (code 72) (name "Net-(J1-Pad14)")
+      (node (ref J1) (pin 14)))
+    (net (code 73) (name "Net-(J1-Pad15)")
+      (node (ref J1) (pin 15)))
+    (net (code 74) (name "Net-(J1-Pad16)")
+      (node (ref J1) (pin 16)))
+    (net (code 75) (name "Net-(J1-Pad17)")
+      (node (ref J1) (pin 17)))
+    (net (code 76) (name "Net-(J1-Pad5)")
+      (node (ref J1) (pin 5)))
+    (net (code 77) (name "Net-(J1-Pad19)")
+      (node (ref J1) (pin 19)))
+    (net (code 78) (name "Net-(J1-Pad20)")
+      (node (ref J1) (pin 20)))
+    (net (code 79) (name "Net-(J1-Pad21)")
+      (node (ref J1) (pin 21)))
+    (net (code 80) (name "Net-(J1-Pad22)")
+      (node (ref J1) (pin 22)))
+    (net (code 81) (name "Net-(J1-Pad23)")
+      (node (ref J1) (pin 23)))
+    (net (code 82) (name "Net-(J1-Pad24)")
+      (node (ref J1) (pin 24)))
+    (net (code 83) (name "Net-(U2-Pad10)")
+      (node (ref U2) (pin 10)))
+    (net (code 84) (name "Net-(U1-Pad3)")
+      (node (ref U1) (pin 3)))
+    (net (code 85) (name "Net-(U1-Pad4)")
+      (node (ref U1) (pin 4)))
+    (net (code 86) (name "Net-(U1-Pad5)")
+      (node (ref U1) (pin 5)))
+    (net (code 87) (name "Net-(U1-Pad6)")
+      (node (ref U1) (pin 6)))
+    (net (code 88) (name "Net-(U1-Pad7)")
+      (node (ref U1) (pin 7)))
+    (net (code 89) (name "Net-(U1-Pad8)")
+      (node (ref U1) (pin 8)))
+    (net (code 90) (name "Net-(U1-Pad9)")
+      (node (ref U1) (pin 9)))
+    (net (code 91) (name "Net-(U2-Pad1)")
+      (node (ref U2) (pin 1)))
+    (net (code 92) (name "Net-(U1-Pad20)")
+      (node (ref U1) (pin 20)))
+    (net (code 93) (name "Net-(U2-Pad11)")
+      (node (ref U2) (pin 11)))
+    (net (code 94) (name "Net-(U2-Pad12)")
+      (node (ref U2) (pin 12)))
+    (net (code 95) (name "Net-(U2-Pad13)")
+      (node (ref U2) (pin 13)))
+    (net (code 96) (name "Net-(U2-Pad14)")
+      (node (ref U2) (pin 14)))
+    (net (code 97) (name "Net-(U2-Pad15)")
+      (node (ref U2) (pin 15)))
+    (net (code 98) (name "Net-(U2-Pad16)")
+      (node (ref U2) (pin 16)))
+    (net (code 99) (name "Net-(U2-Pad2)")
+      (node (ref U2) (pin 2)))
+    (net (code 100) (name "Net-(U2-Pad3)")
+      (node (ref U2) (pin 3)))
+    (net (code 101) (name "Net-(U1-Pad13)")
+      (node (ref U1) (pin 13)))
+    (net (code 102) (name "Net-(J1-Pad6)")
+      (node (ref J1) (pin 6)))
+    (net (code 103) (name "Net-(J1-Pad7)")
+      (node (ref J1) (pin 7)))
+    (net (code 104) (name "Net-(J1-Pad8)")
+      (node (ref J1) (pin 8)))
+    (net (code 105) (name "Net-(J1-Pad9)")
+      (node (ref J1) (pin 9)))
+    (net (code 106) (name "Net-(U1-Pad1)")
+      (node (ref U1) (pin 1)))
+    (net (code 107) (name "Net-(U1-Pad10)")
+      (node (ref U1) (pin 10)))
+    (net (code 108) (name "Net-(U1-Pad11)")
+      (node (ref U1) (pin 11)))
+    (net (code 109) (name "Net-(U1-Pad12)")
+      (node (ref U1) (pin 12)))
+    (net (code 110) (name "Net-(U1-Pad14)")
+      (node (ref U1) (pin 14)))
+    (net (code 111) (name "Net-(U1-Pad15)")
+      (node (ref U1) (pin 15)))
+    (net (code 112) (name "Net-(U1-Pad16)")
+      (node (ref U1) (pin 16)))
+    (net (code 113) (name "Net-(U1-Pad17)")
+      (node (ref U1) (pin 17)))
+    (net (code 114) (name "Net-(U1-Pad18)")
+      (node (ref U1) (pin 18)))
+    (net (code 115) (name "Net-(U1-Pad19)")
+      (node (ref U1) (pin 19)))
+    (net (code 116) (name "Net-(U1-Pad2)")
+      (node (ref U1) (pin 2)))))
\ No newline at end of file
diff --git a/circuit/mainboard/mainboard.pro b/circuit/mainboard/mainboard.pro
new file mode 100644
index 0000000..152769c
--- /dev/null
+++ b/circuit/mainboard/mainboard.pro
@@ -0,0 +1,33 @@
+update=22/05/2015 07:44:53
+version=1
+last_client=kicad
+[general]
+version=1
+RootSch=
+BoardNm=
+[pcbnew]
+version=1
+LastNetListRead=
+UseCmpFile=1
+PadDrill=0.600000000000
+PadDrillOvalY=0.600000000000
+PadSizeH=1.500000000000
+PadSizeV=1.500000000000
+PcbTextSizeV=1.500000000000
+PcbTextSizeH=1.500000000000
+PcbTextThickness=0.300000000000
+ModuleTextSizeV=1.000000000000
+ModuleTextSizeH=1.000000000000
+ModuleTextSizeThickness=0.150000000000
+SolderMaskClearance=0.000000000000
+SolderMaskMinWidth=0.000000000000
+DrawSegmentWidth=0.200000000000
+BoardOutlineThickness=0.100000000000
+ModuleOutlineThickness=0.150000000000
+[cvpcb]
+version=1
+NetIExt=net
+[eeschema]
+version=1
+LibDir=
+[eeschema/libraries]
diff --git a/circuit/mainboard/mainboard.sch b/circuit/mainboard/mainboard.sch
new file mode 100644
index 0000000..44e92e7
--- /dev/null
+++ b/circuit/mainboard/mainboard.sch
@@ -0,0 +1,71 @@
+EESchema Schematic File Version 4
+EELAYER 26 0
+EELAYER END
+$Descr A4 11693 8268
+encoding utf-8
+Sheet 1 1
+Title ""
+Date ""
+Rev ""
+Comp ""
+Comment1 ""
+Comment2 ""
+Comment3 ""
+Comment4 ""
+$EndDescr
+$Comp
+L Connector:Raspberry_Pi_2_3 J1
+U 1 1 5C35F1BF
+P 2500 2300
+F 0 "J1" H 2500 3778 50  0000 C CNN
+F 1 "Raspberry_Pi_2_3" H 2500 3687 50  0000 C CNN
+F 2 "Connector_PinHeader_2.54mm:PinHeader_2x20_P2.54mm_Vertical" H 2500 2300 50  0001 C CNN
+F 3 "https://www.raspberrypi.org/documentation/hardware/raspberrypi/schematics/rpi_SCH_3bplus_1p0_reduced.pdf" H 2500 2300 50  0001 C CNN
+	1    2500 2300
+	1    0    0    -1  
+$EndComp
+$Comp
+L 74xx:74HC245 U1
+U 1 1 5C35F2D7
+P 1950 5850
+F 0 "U1" H 1950 6828 50  0000 C CNN
+F 1 "74HC245" H 1950 6737 50  0000 C CNN
+F 2 "" H 1950 5850 50  0001 C CNN
+F 3 "http://www.ti.com/lit/gpn/sn74HC245" H 1950 5850 50  0001 C CNN
+	1    1950 5850
+	1    0    0    -1  
+$EndComp
+$Comp
+L Analog_Switch:CD4051B U2
+U 1 1 5C35F42C
+P 4850 4600
+F 0 "U2" H 4850 5478 50  0000 C CNN
+F 1 "CD4051B" H 4850 5387 50  0000 C CNN
+F 2 "" H 5000 3850 50  0001 L CNN
+F 3 "http://www.ti.com/lit/ds/symlink/cd4052b.pdf" H 4830 4700 50  0001 C CNN
+	1    4850 4600
+	1    0    0    -1  
+$EndComp
+$Comp
+L Interface_Expansion:MCP23017_SP U4
+U 1 1 5C35F617
+P 4800 2150
+F 0 "U4" H 4800 3428 50  0000 C CNN
+F 1 "MCP23017_SP" H 4800 3337 50  0000 C CNN
+F 2 "Package_DIP:DIP-28_W7.62mm" H 5000 1150 50  0001 L CNN
+F 3 "http://ww1.microchip.com/downloads/en/DeviceDoc/20001952C.pdf" H 5000 1050 50  0001 L CNN
+	1    4800 2150
+	1    0    0    -1  
+$EndComp
+$Comp
+L 74xx:74LS138 U3
+U 1 1 5C35F892
+P 7800 1350
+F 0 "U3" H 7800 2128 50  0000 C CNN
+F 1 "74LS138" H 7800 2037 50  0000 C CNN
+F 2 "" H 7800 1350 50  0001 C CNN
+F 3 "http://www.ti.com/lit/gpn/sn74LS138" H 7800 1350 50  0001 C CNN
+	1    7800 1350
+	1    0    0    -1  
+$EndComp
+$EndSCHEMATC