Arduino

You can download old Arduino (ver 1.8) to Programs, or you can use from Ubuntu (ver 2.1).

Arduino Makefile

I use Arduino Makefile to compile and flash to arduino https://github.com/sudar/Arduino-Makefile

sudo apt-get install arduino-mk

It gives some files https://packages.ubuntu.com/xenial/all/arduino-mk/filelist I could ignore path to arduino dir since I used system arduino

# ~/config/bashrc/arduino.sh
export ARDUINO_DIR=/usr/share/arduino
export ARDMK_DIR=/usr/share/arduino/

So for your project you have to define

# Makefile
BOARD_TAG    = uno
ARDUINO_PORT = /dev/ttyACM0
include $(ARDMK_DIR)/Arduino.mk

In vim you can run

make
make upload
make monitor
# you can exit with Ctrl+C or Ctrl+A + K (and y)
make show_boards

In case you have an error avrdude: can't open config file "/usr/../avrdude.conf": No such file or directory than define in makefile AVRDUDE_CONF = /etc/avrdude.conf

Ignore build files

#.gitignore
build-uno/

To exit from serial monitor (screen or minicom, which I could not setup to work from makefile) you can Ctrl + A and than K and than Y

Low cost tx rx

VirtualWire works fine on ATMEGA Follow installation http://www.airspayce.com/mikem/arduino/VirtualWire/ and download zip and extract to sketchbook/libraries in my case is /home/orlovic/Arduino/libraries. Than you can find examples of it: File -> Examples -> VirtualWire -> transmitter Pin 12 is for sending, Pin 11 for receiving.

But since it is not updated I used Manchester http://mchr3k.github.io/arduino-libs-manchester/

Solar food dehydrator

https://www.youtube.com/results?search_query=solar+food+dehydrator

Air quality monitor

https://github.com/carldunham/air-quality-monitor/tree/cd/initial-implementation