Knowledge Base

This is the official Knowledge Base created by okinesio Labs.
Here you find useful information about our development process as well as content about our experience during the project.


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

We are exited to announce that we launched our new Knowledge Base, where we will publish articles relating our experiences during development.


We will update it from time to time. So stay tuned!
For now you can follow us on Twitter @okinesioLab

This article outlines a walk-through on how to make your own Arduino board (even if you are not into electrical engineering – but you may get yourself familiar during the progress).

Let me build my own ...

Pedometers in general

Common electronic pedometers (e.g. activity trackers) are equipped with an digital triple-axis accelerometer (3-DOF) which measures the acceleration of the three directions (X, Y, Z). With an algorithm parsing the values in the background, steps can be detected on a specific pattern. The accuracy of detection mostly depends on a good algorithm. Some trackers additionally use multiple sensors such as an accelerometer and a gyroscope (6-DOF or even more) for precise determination on the hardware side.

You can find plenty information about accelerometers on the internet (if you’re interested in this topic).

Read more ...