Experiments with my Raspberry Pi 3 Model B
These experiments are based on the lesson plans from the web site of OsoYoo which sells the Raspberry Pi Starter Kit which is what is being used for these projects.
See URL: http://osoyoo.com/2017/07/13/raspberry-pi-3-starter-learning-kit-introduction/
The RPi Hub on eLinux.org has a ton of information https://elinux.org/RPi_Hub
Each project stored within this repository is in a folder with a README.md file. There are also pages in the repository wiki.
The project source code is in the C or C++ programming language and uses the wiringPi library in order to interface with the Raspberry Pi GPIO board. The wiringPi library has been ported to other languages that support C calls. And there are other libraries that provide similar functionality as the wiringPi library.
Thus far I have seen GPIO interfaces for python, JavaScript, and Lua in addition to C. All of these languages are available on the Raspberry Pi.
WARNING: Be careful about the pins connected and used in experiments. The Raspberry Pi GPIO board has both 3.3v and 5v power pins. You can overload the I/O pins, which are 3.3v, by connecting them accidently to the 5v pin and render your Raspberry Pi dead.
See the Wiki page about the Broadcom board and the GPIO interface.
These may also work with an Orange Pi 5 using the wiringOP library at https://github.com/orangepi-xunlong/wiringOP instead of wiringPi library.
I have just purchased an Orange Pi 5 Plus and have Ubuntu running on it. I plan to run a few tests with some of these projects. The Orange Pi 5 seems to have a similar physical pinout for the 40 GPIO pins as the Raspberry Pi 3 however the pin addressing is a bit different.
Breadboarding guidelines - http://nreeder.com/eet1131/breadboardingTips.htm
Most plastic breadboard are actually three pieces that are connected together with an adhesive backing securing the three pieces into a single board. The ability to separate these three pices can make breadboards a bit more flexible with unusual sized components.
There are two power rail sections, one on each side, which each have two columns (+ column and - column) of tie points that are vertically connected. Each row has a tie point to provide a power point and a ground point. This arrangement allows multiple tie points to access the power rail on each side.
The middle section is a single piece with a gutter down the middle to electrically isolate the sub-sections on each side of the central gutter. The idea is that one power rail is used to provide power and ground to one side of the gutter and the other power rail to provide power and ground for the other side of the gutter.
With some microelectronics such as the ESP32 microcontroller the distance between the pins on each side of the physical package are so large that it will not fit properly on the middle section of a breadboard across the gutter so that you have access to the pins on each side while the pins are also isolated.
One approach is to use two breadboards togther to create a gap of the necessary width. However with most breadboards the width of the power rail section is sufficient as to make this appoach unworkable due to the width of the two power rail sections that are side by side. One solution is to take one of the two breadboards and remove one of the power rail sections. Then the two breadboards can be used together such that instead of having a gap that is as wide as two power rail sections, you now have a gap as wide as a single power rail section.
Nick Reeder's Home page with access to various electronics topics - http://nreeder.com/
Remove After Washing label on Piezo buzzer - https://electronics.stackexchange.com/questions/98556/remove-after-washing-on-piezo-buzzer
Tutorial on Serial Communications https://learn.sparkfun.com/tutorials/serial-communication
Tutorial on Serial Peripheral Interface (SPI) https://learn.sparkfun.com/tutorials/serial-peripheral-interface-spi
Tutorial on Inter-integrated Circuit (I2C) https://learn.sparkfun.com/tutorials/i2c
Tutorial on Pull-up Resistors https://learn.sparkfun.com/tutorials/pull-up-resistors
The answers to this question are quite educational about pull-up resistors. How do I calculate the required value for a pull-up resistor? https://electronics.stackexchange.com/questions/23645/how-do-i-calculate-the-required-value-for-a-pull-up-resistor
Also on pull-up resistors, I2C Bus Pullup Resistor Calculation http://www.ti.com/lit/an/slva689/slva689.pdf
This slide share package of some 60 slides does a compare and contrast between four different IoT protocols looking at the needs of two different IoT groups, Consumers and Industrial, which have differing needs for reliability and robustness. What's the Right Messaging Standard for the IoT?.
There are several message broker server alternatives with RabbitMQ being one of the most well known.
RabbitMQ https://www.rabbitmq.com/
VerneMQ https://vernemq.com/
Apache ActiveMQ http://activemq.apache.org/
The following article provides an overview of three of the most commonly used protocols: AMQP, MQTT, and STOMP. There is CoAP as well
Choosing your messaging protocoll: AMQP, MQTT, or STOMP https://blogs.vmware.com/vfabric/2013/02/choosing-your-messaging-protocol-amqp-mqtt-or-stomp.html
STOMP materials are at https://stomp.github.io/
AMQP materials are at https://www.amqp.org/
CoAP materials are at http://coap.technology/
CBOR materials are at http://cbor.io/
See as well the following:
- All About Messaging Protocols: What Are the Differences? http://www.eejournal.com/article/20150420-protocols/
- IoT Standards and Protocols https://www.postscapes.com/internet-of-things-protocols/
- MQTT and CoAP, IoT Protocols https://www.eclipse.org/community/eclipse_newsletter/2014/february/article2.php
- Practical MQTT with Paho https://www.infoq.com/articles/practical-mqtt-with-paho
- MQTT community wiki in GitHub https://github.com/mqtt/mqtt.github.io/wiki
- Adafruit Message Queue Telemetry Transport https://learn.adafruit.com/adafruit-io/mqtt-api
- Simple Messaging with MQTT (Java) https://www.oracle.com/corporate/features/simple-messaging-with-mqtt.html
- Reliable message delivery with Mosquitto (MQTT) https://www.electricmonk.nl/log/2017/02/20/reliable-message-delivery-with-mosquitto-mqtt/
For explorations into the underlying MQTT protocol see the following:
- IoT – MQTT Publish and Subscriber C Code https://blog.feabhas.com/2012/04/iot-mqtt-publish-and-subscriber-c-code/
MQTT Protocol Overview -Beginners Guide http://www.steves-internet-guide.com/mqtt/
MQTT 101 – How to Get Started with the lightweight IoT Protocol https://www.hivemq.com/blog/how-to-get-started-with-mqtt
Getting started with MQTT https://dzone.com/refcardz/getting-started-with-mqtt
CoAP web site http://coap.technology/
CoAP Messaging in Depth http://programmingwithreason.com/article-iot-coap.html