diff --git a/.arduino-ci.yml b/.arduino-ci.yml
index 319d7302..1e394c06 100644
--- a/.arduino-ci.yml
+++ b/.arduino-ci.yml
@@ -1,4 +1,22 @@
-  
+platforms:
+  mega2560:
+    board: arduino:avr:mega:cpu=atmega2560
+    package: arduino:avr
+    gcc:
+      features:
+      defines:
+        - __AVR__
+        - __AVR_ATmega2560__
+        - ARDUINO_ARCH_AVR
+        - ARDUINO_AVR_MEGA2560
+        # Why aren't these already provided elsewhere?
+        - SS=1
+        - MOSI=2
+        - MISO=3
+        - SCK=4
+      warnings:
+      flags:
+
 unittest:
     platforms:
         - mega2560
@@ -8,6 +26,7 @@ unittest:
       - "Ethernet"
       - "LiquidCrystal"
       - "RTClib"
+      - "SD"
 
 compile:
     platforms:
@@ -18,3 +37,4 @@ compile:
       - "Ethernet"
       - "LiquidCrystal"
       - "RTClib"
+      - "SD"
diff --git a/Gemfile b/Gemfile
index 80468b55..fb422d12 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,2 +1,2 @@
 source 'https://rubygems.org'
-gem 'arduino_ci', git: 'https://github.com/Arduino-CI/arduino_ci.git', branch: 'master'
+gem 'arduino_ci'
diff --git a/src/Devices/SD_TC.cpp b/src/Devices/SD_TC.cpp
new file mode 100644
index 00000000..0672efee
--- /dev/null
+++ b/src/Devices/SD_TC.cpp
@@ -0,0 +1,54 @@
+#include "Devices/SD_TC.h"
+
+//  class variables
+SDClass_TC* SDClass_TC::_instance = nullptr;
+
+//  class methods
+/**
+ * accessor for singleton
+ */
+SDClass_TC* SDClass_TC::instance() {
+  if (!_instance) {
+    _instance = new SDClass_TC();
+  }
+  return _instance;
+}
+
+//  instance methods
+/**
+ * Constructor sets pins, dimensions, and shows splash screen
+ */
+SDClass_TC::SDClass_TC() : SDClass() {
+  pinMode(10, OUTPUT);
+  digitalWrite(10, HIGH);
+  // TODO: Need to re-enable this for the physical device
+  // begin(4);
+}
+
+void SDClass_TC::printRootDirectory() {
+  File root = open("/");
+  printDirectory(root, 0);
+}
+
+void SDClass_TC::printDirectory(File dir, int numTabs) {
+  while (true) {
+    File entry = dir.openNextFile();
+    if (!entry) {
+      // no more files
+      break;
+    }
+    for (uint8_t i = 0; i < numTabs; i++) {
+      Serial.print('\t');
+    }
+    Serial.print(entry.name());
+    if (entry.isDirectory()) {
+      Serial.println(F("/"));
+      printDirectory(entry, numTabs + 1);
+    } else {
+      // files have sizes, directories do not
+      Serial.print(F("\t\t"));
+      Serial.println(entry.size(), DEC);
+    }
+    entry.close();
+  }
+}
diff --git a/src/Devices/SD_TC.h b/src/Devices/SD_TC.h
new file mode 100644
index 00000000..453f47f4
--- /dev/null
+++ b/src/Devices/SD_TC.h
@@ -0,0 +1,26 @@
+#pragma once
+
+#include <Arduino.h>
+#ifdef MOCK_PINS_COUNT
+#include <SD_CI.h>
+#else
+#include <SD.h>
+#endif
+
+class SDClass_TC : public SDClass {
+public:
+  // class methods
+  static SDClass_TC* instance();
+  // instance methods
+  void printRootDirectory();
+  // bool begin(uint8_t csPin = SD_CHIP_SELECT_PIN);
+  // bool begin(uint32_t clock, uint8_t csPin);
+
+private:
+  // class variables
+  static SDClass_TC* _instance;
+
+  // instance methods
+  SDClass_TC();
+  void printDirectory(File dir, int numTabs);
+};
diff --git a/src/TankControllerLib.cpp b/src/TankControllerLib.cpp
index c138ede6..b1cdc519 100644
--- a/src/TankControllerLib.cpp
+++ b/src/TankControllerLib.cpp
@@ -37,6 +37,7 @@ TankControllerLib::TankControllerLib() {
   lcd = LiquidCrystal_TC::instance();
   log = Serial_TC::instance();
   log->print(F("TankControllerLib::TankControllerLib() - version "), TANK_CONTROLLER_VERSION);
+  SDClass_TC::instance()->printRootDirectory();
 }
 
 /**
diff --git a/src/TankControllerLib.h b/src/TankControllerLib.h
index fecb7098..636f2cf8 100644
--- a/src/TankControllerLib.h
+++ b/src/TankControllerLib.h
@@ -2,6 +2,7 @@
 #include <Arduino.h>
 
 #include "Devices/LiquidCrystal_TC.h"
+#include "Devices/SD_TC.h"
 #include "Devices/Serial_TC.h"
 
 const char TANK_CONTROLLER_VERSION[] = "0.3.0";
diff --git a/test/SD.cpp b/test/SD.cpp
new file mode 100644
index 00000000..8efa8971
--- /dev/null
+++ b/test/SD.cpp
@@ -0,0 +1,13 @@
+#include <Arduino.h>
+#include <ArduinoUnitTests.h>
+
+#include "TankControllerLib.h"
+
+unittest(test) {
+  TankControllerLib* tank = TankControllerLib::instance();
+  SDClass_TC* sd = SDClass_TC::instance();
+  assertTrue(tank != nullptr);
+  assertTrue(sd != nullptr);
+}
+
+unittest_main()