Add project files

attiny_firmware/.gitignore

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+.pio
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch

attiny_firmware/.vscode/extensions.json

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+{
+    // See http://go.microsoft.com/fwlink/?LinkId=827846
+    // for the documentation about the extensions.json format
+    "recommendations": [
+        "platformio.platformio-ide"
+    ],
+    "unwantedRecommendations": [
+        "ms-vscode.cpptools-extension-pack"
+    ]
+}

attiny_firmware/include/README

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+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with `.h'.
+It is most portable to use only letters, digits, dashes, and underscores in
+header file names, and at most one dot.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

attiny_firmware/lib/README

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+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into executable file.
+
+The source code of each library should be placed in an own separate directory
+("lib/your_library_name/[here are source files]").
+
+For example, see a structure of the following two libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional, custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+and a contents of `src/main.c`:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+PlatformIO Library Dependency Finder will find automatically dependent
+libraries scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

attiny_firmware/platformio.ini

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+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:attiny85]
+platform = atmelavr
+board = attiny85
+framework = arduino
+upload_protocol = custom
+upload_port = /dev/ttyACM0
+upload_speed = 19200
+upload_flags =
+    -C
+    ${platformio.packages_dir}/tool-avrdude/avrdude.conf
+    -p
+    $BOARD_MCU
+    -P
+    $UPLOAD_PORT
+    -b
+    $UPLOAD_SPEED
+    -c
+    stk500v1
+upload_command = avrdude $UPLOAD_FLAGS -U flash:w:$SOURCE:i
+lib_deps = connornishijima/TinySnore@^1.0.1
+
+monitor_speed=115200
+board_build.f_cpu=1000000L
+board_fuses.lfuse = 0x62
+board_fuses.hfuse = 0xD7
+board_fuses.efuse = 0xFF

attiny_firmware/src/main.cpp

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+#include "tinysnore.h"
+#include <Arduino.h>
+
+// Define to enable serial debug
+// messages on pin 1
+#define debug
+
+// Pin connected to the ESP-01's CH_PD pin (Pin 3)
+#define esp_enable_pin 4
+// Pin connected to the ESP-01's feedback pin (UTXD / Pin 1)
+#define esp_status_pin 3
+
+// Wake up the ESP-01 every 5 minutes
+const long update_interval = 1000L * 60L * 5L;
+// Cut power to the ESP-01 if the update takes longer than 30 seconds
+const long update_timeout = 1000L * 30L;
+
+#ifdef debug
+#include <SoftwareSerial.h>
+SoftwareSerial Debug(PB0, PB1);
+#endif
+
+void setup() {
+#ifdef debug
+  Debug.begin(9600);
+  Debug.println("-> Reset");
+#endif
+  pinMode(esp_enable_pin, OUTPUT);
+  pinMode(esp_status_pin, INPUT_PULLUP);
+}
+
+unsigned long runESP() {
+  // Reset the ESP
+  digitalWrite(esp_enable_pin, LOW);
+  snore(100);
+  digitalWrite(esp_enable_pin, HIGH);
+  // Wait 0.2s for the ESP to boot up
+  snore(200);
+  // Wait until either the status pin gets pulled HIGH
+  // by the ESP or `update_timeout` milliseconds have passed
+  unsigned long elapsed_time_ms = 0;
+  while (digitalRead(esp_status_pin) == LOW &&
+         elapsed_time_ms < update_timeout) {
+    snore(100);
+    elapsed_time_ms += 100;
+  }
+  // Turn off the ESP
+  digitalWrite(esp_enable_pin, LOW);
+
+  // Return time the mcu was asleep
+  return 100L + 200L + elapsed_time_ms;
+}
+
+void loop() {
+  // Store the current time
+  unsigned long start_time = millis();
+#ifdef debug
+  Debug.print("Start time: ");
+  Debug.println(start_time);
+  Debug.println("-> Running ESP");
+#endif
+  // Run the ESP and store the sleep time
+  long elapsed_asleep = runESP();
+  // Calculate elapsed time the mcu was awake
+  long elapsed_awake = millis() - start_time;
+  // Calculate the total elapsed time
+  long delta_time = elapsed_awake + elapsed_asleep;
+  // Sleep until next interval
+  long sleep_time = max(0, update_interval - delta_time);
+#ifdef debug
+  Debug.println("-> ESP Done");
+  Debug.print("Took: ");
+  Debug.println(delta_time);
+  Debug.print("-> Sleeping for ");
+  Debug.println(sleep_time);
+#endif
+  snore(sleep_time);
+}

attiny_firmware/test/README

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+
+This directory is intended for PlatformIO Test Runner and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PlatformIO Unit Testing:
+- https://docs.platformio.org/en/latest/advanced/unit-testing/index.html