As the title suggests, this is a loose collection of resources, articles and links that might be interesting.
We are not responsible for content of external sites.
Guide for practical electronics
https://en.wikibooks.org/wiki/Practical_Electronics
https://en.wikibooks.org/wiki/Practical_Electronics/PCB_Layout
https://www.allaboutcircuits.com/textbook
Articles
Hardware Design should be free
http://www.wired.com/2015/03/richard-stallman-how-to-make-hardware-designs-free
Build It. Share It. Profit. Can Open Source Hardware Work?
https://www.wired.com/2008/10/ff-openmanufacturing
Producing / Selling
How to turn an Arduino-based proof of concept into a final prototype
http://digitaljunky.io/how-to-turn-an-arduino-based-proof-of-concept-into-a-final-prototype
From Prototype to Kickstarter to Production: How blink(1) was made
https://www.slideshare.net/todbotdotcom/blink1-talkmakerfaire2013nonotes
via Sparkfun (Producing and/or Selling)
https://learn.sparkfun.com/tutorials/how-to-sell-your-widget-on-sparkfun
via Seeestudio
https://www.seeedstudio.com/propagate
Licensing
Compatible licenses with GPL
https://www.gnu.org/licenses/license-list.en.html#GPLCompatibleLicenses
Low Power
Good resource for low power practice
http://www.gammon.com.au/power
Adventures in Low Power Land (reducing power step-by-step)
https://www.sparkfun.com/tutorials/309
General information about sleep modes (German)
http://www.mikrocontroller.net/articles/Sleep_Mode
Innovative Techniques for Extremely Low Power Consumption with 8-bit Microcontrollers
http://www.atmel.com/images/doc7903.pdf
Measure Battery Level
Secret Arduino Voltmeter – Measure Battery Voltage (fast & w/out any external components)
http://provideyourown.com/2012/secret-arduino-voltmeter-measure-battery-voltage
What if we want to know the battery state?
http://jeelabs.org/2013/05/15/what-if-we-want-to-know-the-battery-state/index.html
Measuring Battery Capacity With an Arduino
http://denishennessy.com/2012/04/08/measuring-battery-capacity-with-an-arduino
Crystals, Resonators & Oscillators
Notable Guide about Crystal oscillators (recommended)
http://www.ecsxtal.com/store/pdf/Oscillation-Circut-Design-Considerations.pdf
Best practices for PCB layouts of oscillators
http://www.atmel.com/images/doc8128.pdf
General information about Oscillators
https://www.sparkfun.com/tutorials/95
Guide for choosing the right caps for a quartz crystal
https://blog.adafruit.com/2012/01/24/choosing-the-right-crystal-and-caps-for-your-design
Short insight about Cstray and Caps (Answer on StackExchange)
http://electronics.stackexchange.com/questions/17891/stray-capacitance-for-crystals
FAQ about Oscillators
http://www.commutek.com/?p=20
Using a Crystal Resonator with a Microcontroller
http://kdelectronics.blogspot.de/2013/03/using-crystal-resonator-with.html
Good information sheet about oscillators
http://www.st.com/web/en/resource/technical/document/application_note/CD00221665.pdf
Detailed article about crystal design
https://www.maximintegrated.com/en/app-notes/index.mvp/id/5265
Forum post about crystals
http://www.avrfreaks.net/comment/264222#comment-264222
Internal clock on Atmel microcontrollers
http://electronics.stackexchange.com/questions/160921/when-we-need-external-crystal-for-atmega
AVR053: Calibration of the internal RC oscillator
http://www.atmel.com/images/doc2555.pdf
Protocols
SPI protocol
https://learn.sparkfun.com/tutorials/serial-peripheral-interface-spi
I2C protocol
https://learn.sparkfun.com/tutorials/i2c
Bootloader
General information about Bootloader & Arduino
https://learn.sparkfun.com/tutorials/installing-an-arduino-bootloader
Information uploading a Bootloader via Arduino
https://www.arduino.cc/en/Hacking/MiniBootloader
DFU Programming and uploading firmware with Arduino
https://www.arduino.cc/en/Hacking/DFUProgramming8U2
Programming ATMEGA32U4 through USB
http://electronics.stackexchange.com/questions/185846/programming-an-atmega32u4-through-usb
ATMEL USB DFU Bootloader (Datasheet)
http://www.atmel.com/Images/doc7618.pdf
USB Bootloader (AVRUSBBoot)
http://www.fischl.de/avrusbboot
ISP programming
AVR Fuse Calculator
http://www.engbedded.com/fusecalc
Avrdude commands / overview
http://www.ladyada.net/learn/avr/avrdude.html
Example process avrdude
http://blog.spitzenpfeil.org/wordpress/2009/04/03/flashing-the-bootloader-with-usbtinyispavrdude
Hint: Other wires on ISP could loading down the signals
http://forum.arduino.cc/index.php?topic=324881.15#20
AVR910 (Page 3) > add pull-up resistors if lines are used by SPI devices
http://www.atmel.com/images/doc0943.pdf
AVR042 (Page 7) > information about using pull-ups when using ISP and SPI devices
http://www.atmel.com/Images/Atmel-2521-AVR-Hardware-Design-Considerations_ApplicationNote_AVR042.pdf
Further information about pull-up resistors when using SPI
https://www.kanda.com/avr-isp-circuits.html&h=177&w=274&tbnid=U4uMuDXuo0RImM:&zoom=1&tbnh=90&tbnw=139&usg=__iTEc9_ef_X60E5m2I7fCDF5MabQ=&docid=AGGJf83fI99mHM
Solder Technics
Solder QFN/SMD-Packages (for Demonstration/Know How)
https://www.youtube.com/watch?v=M_rO6oPVsws
Reflow Process
https://www.youtube.com/watch?v=FNNRoXZom30
Know-How
Basics about diodes
https://learn.sparkfun.com/tutorials/diodes
Differences between different descriptions on oscillators
http://electronics.stackexchange.com/questions/86676/what-is-crystal-resonator-crystal-resonator-crystal-oscillator?lq=1
Capacitors: Read the datasheet. As the capacity can massively drop when temperature rises
https://www.maximintegrated.com/en/app-notes/index.mvp/id/5527
Further information about DC Bias characteristics
https://product.tdk.com/info/en/products/capacitor/ceramic/mlcc/technote/solution/mlcc03/index.html#anc04
http://www.murata.com/en-sg/support/faqs/products/capacitor/mlcc/char/0005
Video describing DC Bias characteristics and how to minimize capacity loss
https://product.tdk.com/info/en/contact/faq/faq_detail_D/1432616875432.html
Does capacitor size matter
http://www.avrfreaks.net/forum/does-capacitor-size-matter
Low forward voltage Schottky Diode (application note)
http://www.st.com/st-web-ui/static/active/en/resource/technical/document/application_note/CD00003953.pdf
Difference between different types of diodes
https://blog.adafruit.com/2012/03/06/an-answer-to-your-question-14-what-is-the-difference-between-the-different-types-of-diodes
Diode ratings explained
http://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/diode-ratings