The ANAVI Macro Pad 12 and ANAVI Arrows have received official certification from the Open Source Hardware Association (OSHWA). OSHWA, a non-profit organization based in the United States, manages the Certified Projects Directory and hosts the annual Open Hardware Summit. Notably, the summit takes place in different cities, and in 2024, it is scheduled to be held in Montreal, Canada.
The certification program by OSHWA ensures that a project’s understanding of “open source hardware” is in harmony with the wider community’s definition of open source hardware. Subsequently, OSHWA assigns a unique identification number (UID) to every certified hardware version. This UID commonly comprises a blend of a country code and a numerical sequence, ensuring that each certified hardware version possesses a distinct identifier. For our two new keyboards, the UIDs are:
The OSHW Certification Mark serves a dual role: not only does it display the project’s unique certification ID, but it also streamlines navigation and information retrieval. In this context, the “BG” prefix signifies the country code for Bulgaria, indicating that these mechanical keyboards are crafted in Plovdiv, the second-largest city in Bulgaria and the oldest continually inhabited European city with over 6000 years of history. What sets our keyboards apart is their complete adherence to open-source principles. This means that every facet of their design and functionality is open and freely accessible to everyone. Our dedication to openness extends to utilizing only free and open source software in various project aspects, including designing the printed circuit board, creating acrylic enclosures, developing firmware, and thoroughly documenting the entire process.
The printed circuit boards for ANAVI Arrows and ANAVI Macro Pad 12 were designed with the open source software KiCad on Ubuntu Linux distribution. Furthermore, we use open source firmware called KMK, written in CircuitPython. Soon QMK firmware will be also ported to both keyboards. Open source ensures transparency, sharing knowledge and hopefully fostering collaboration and innovation within the community.
In the world of electronics and IoT, gesture recognition has emerged as a fascinating and practical technology. Whether it’s controlling your favorite gadgets with the wave of a hand or adding a touch of magic to your projects, gesture recognition sensors play a pivotal role. Among the numerous sensors available, the APDS9960 stands out as a versatile and widely used I2C sensor at a very affordable price. In this blog post, we will take you on a journey through the fascinating world of gesture recognition using the APDS9960 sensor on a Raspberry Pi and any of our popular add-on boards: ANAVI Infrared pHAT, ANAVI Light pHAT, ANAVI Gardening uHAT, ANAVI Info uHAT as well as ANAVI Miracle uHAT and ANAVI CO2 uHAT (both of which are in final development).
What is APDS9960?
APDS9960 is an I2C (Inter-Integrated Circuit) sensor produced by Broadcom (formerly Avago Technologies). It is known for its versatility and is commonly used for gesture recognition, proximity sensing, ambient light sensing, and color sensing applications. Gestures are detected at a distance of 10 to 20 cm. The sensor has built-in UV and IR filters for better recognition. Its wide range of applications makes it a favorite choice among electronics enthusiasts, engineers, and hobbyists. Ovewr the years APDS9960 has been integrated in many popular consumer electronic devices, including Samsung Galaxy S5 smartphone.
In this tutorial, we will explore how to set up gesture detection on a Raspberry Pi running the Raspberry Pi OS Linux distribution. Specifically, we will use the APDS9960 I2C sensor connected to a Raspberry Pi uHAT (add-on board) and a mini OLED SSD1306 I2C yellow-blue display.
🔌 Hardware Setup
Both APDS9960 sensor and the mini yellow-blue SSD1306 OLED display rely on the serial communication protocol I2C that allows multiple electronic devices to communicate with each other using only two wires: serial data (SDA) and serial clock (SCL). Raspberry Pi single board computers have two different I2C busses. The primary I2C bus is at GPIO 2 (physical pin 3 for SDA) and GPIO3 (physical pin 6 for SCL). These pins should be used to attach APDS9960 and the mini OLED display to the Raspberry Pi. Also APDS9960 should be connected to 3.3V and GND pins of the Raspberry Pi to be powered. This makes 4 wires in total to attach the sensor. ANAVI HATs (Hardware Attached on Top) for Raspberry Pi offer dedicated slots for I2C sensors. On ANAVI Info uHAT and ANAVI CO2 uHAT there are even dedicated slots for the mini OLED display.
Of course the OLED display is optional and as an alternative we offer a simple command-line Python3 example for APDS9960 which can function without the OLED display.
The heart of our demonstration are scripts written in the Python 3 programming language. We’ve tailored the script to work seamlessly with Raspberry Pi OS, but it should also run smoothly on any other GNU Linux distribution. These scripts rely on popular Python3 libraries like PIL and Luma OLED. You can find the source code on GitHub for reference and further experimentation: https://github.com/AnaviTechnology/anavi-examples/tree/master/sensors/APDS-9960/python
There are two different Python 3 scripts to demonstrate APDS9960 gesture detection:
gesture-oled.py for detecting gestures and showing them on the mini OLED display as in the video
gesture.py for detecting gesture and printing them in the command-line interface (use this one if don’t have a suitable mini OLED display)
👁️ Real-Time Gesture Detection
Experience the magic as the APDS9960 sensor detects your hand movements, including swipes, taps, and more. Witness how your Raspberry Pi interprets and responds to these gestures in real-time, opening up a world of interactive possibilities. The video provides insights into potential issues you might face during setup and offers practical tips to ensure a seamless experience.
After our crowdfunding campaign concluded successfully, we immediately started the manufacturing phase without delay. Thankfully, we had the foresight to ensure we had all the necessary components in stock ahead of time. Just recently, we happily received the first batch of ANAVI Arrows and Macro Pad 12 printed circuit boards, which are adorned with surface mount components on both sides.
We are already in the process of locally producing our second batch, and we expect it to be ready by the end of September. These printed circuit boards are meticulously gold-plated to guarantee the highest quality.
Additionally, the acrylic enclosures were laser cutted in August. Our next steps include programming CircuitPython and the KMK firmware, testing, and packaging all keyboards.
Once again,thank you for your support of ANAVI Macro Pad 12 and ANAVI Arrows. Stay tuned for more exciting updates in the coming weeks!
I2C (Inter-Integrated Circuit) is a popular serial communication protocol that allows multiple integrated circuits to communicate with each other over a short distance, typically limited to a few meters. Each device on the bus has a unique address, identifying it and allowing it to communicate individually. The protocol was developed by Philips (now NXP Semiconductors) in the 1980s. Over the years it has become a standard for communication between various electronic components in embedded devices. I2C can be used to connect various peripherals, such as sensors, displays and EEPROMs. The mini OLED yellw-blue displays on our compact mechanical keyboards ANAVI Macro Pad 12 and ANAVI Arrows are connected to the Raspberry Pi RP2040 microcontrollers over I2C.
I2C is easy to use becase it requires only two wires for communication:
SDA (Serial Data) for transmitting and receiving data between devices
SCL (Serial Clock) for a clock signal to synchronizes the data transfer between the devices
The core component of our hot-swappable mechanical keyboards ANAVI Macro Pad 12 and ANAVI Arrows is Seeed Studio XIAO RP2040 module. This is actually a tiny development board suitable for surface-mount technology (SMT) assembly and equipped with a Raspberry Pi RP2040 32-bit dual-core ARM Cortex M0+ MCU, 264 KB SRAM, 2 MB Flash memory, 11 GPIO pins and USB-C connector. The I2C interface is located on pins D4 (for SDA) and D5 (for SCL) of XIAO RP2040.
A yellow-blue mini OLED I2C display is included in all kits with ANAVI Macro Pad 12 and ANAVI Arrows. It has 4 pins: GND (ground), VCC (supply voltage), SCL, and SDA. This display relies on SSD1306, a single-chip CMOS OLED/PLED driver with controller for organic / polymer light emitting diode dot-matrix graphic display system which consists of 128 segments and 64 commons. It is the same display we include in our other mechanical keyboards like the ANAVI Macro Pad 10 and ANAVI Macro Pad 8, Internet of Things devices like the ANAVI Thermometer and ANAVI Gas Detector, tools like ANAVI Fume Extractor, and Raspberry Pi add-on boards like ANAVI Info uHAT. This versatile mini OLED display is a great fit for many projects, You can pick one up at Mouser if you need a spare.
There is a dedicated slot for the display on the printed circuit board. Just plug the mini OLED display into it and then connect the mechanical keyboard to a computer. In every kit with ANAVI Macro Pad 12 and ANAVI Arrows, you will find four additional male-to-female jumper wires included, providing you with an exciting opportunity to get creative with your project. If you decide to design your own 3D printed case for the keyboard, these jumper wires may become handy. They grant you the flexibility to reposition the mini OLED display to a location of your choice within the case.
ANAVI Macro Pad 12 is compatible the two most popular open source firmwares for mechanical keyboards: KMK and QMK. KMK is written in CircuitPython and QMK in the C programming language. Both support OLED displays over I2C.
Makers with advanced skills have a fantastic opportunity to extend the capabilities of the keyboard project by adding more I2C peripherals. Using a breadboard and without any soldering, makers can easily connect additional I2C peripherals, such as sensors or other modules that communicate via I2C, to the existing setup. This allows them to expand the project’s functionalities and explore various creative ideas. Those seeking a more permanent and tailored extension can even design their own custom I2C add-on printed circuit board. The mini OLED displays included in the kits work out of the box, but it is important to be aware that incorporating any other I2C devices into the keyboard will require adjusting the KMK firmware to support the additions.
Support our crowdfunding campaign and get the open source mechanical keyboards ANAVI Macro Pad 12 and ANAVI Arrows with a mini OLED display for real-time notifications and customizable graphics at your fingertips. Learn how to use I2C and unleash your creativity by extending the keyboard with additional peripherals!
Within the realm of computer keyboards, a remarkable open-source firmware called KMK has surfaced, captivating enthusiasts from all corners. KMK possesses a potent capability to revolutionize mechanical keyboards into personalized instruments, enabling users to venture into uncharted territories of customization and productivity.
CircuitPython is an open-source programming language that runs on microcontrollers used in various embedded applications, including mechanical keyboards like ANAVI Macro Pad 12 and ANAVI Arrows from our crowdfunding campaign at Crowd Supply. Built upon the foundations of Python, CircuitPython is specifically crafted to cater to the requirements of resource-limited embedded devices housing microcontrollers. One of the standout merits of CircuitPython lies in its user-friendly nature and effortless adaptability, particularly beneficial for newcomers who may not possess extensive coding expertise.
The source code of KMK is readily available on GitHub, released under the GPLv3 license. The inception of KMK can be traced back to 2018. Notably, the KMK source code follows a coding style that employs the Python code formatter, known as Black, and embraces the usage of single quotes.
The hardware requirements for microcontrollers to run KMK are: a minimum of 256KB of flash storage, support HID over USB and/or Bluetooth, CircuitPython version 7.0 or newer. With its impressive hardware capabilities, the Raspberry Pi RP2040 microcontroller is a perfect fit for CircuitPython and KMK. Because of this we selected Seeed Studio’s XIAO module with RP2040 for ANAVI Macro Pad 12 and ANAVI Arrows.
KMK offers many key features:
Key Mapping: Customize key assignments to suit individual preferences
Macros: Create and assign macros for automating tasks or executing commands
Layers: Define multiple virtual layers for accessing different functions or modes
LED Control: Customize backlighting and LED behavior
Rotary Encoder: Rotary encoders for various functions like volume control or scrolling.
Mini OLED Display: Compatibility with mini OLED displays, allowing users to display custom information or visuals on their keyboards
As part of the covered stretch goals, each kit will include stickers from ANAVI Technology and KiCad, the free and open source CAD software used for designing the printed circuit boards of the keyboards. Furthermore, ANAVI Macro Pad 10 kits will include 32 super-cool emoji stickers. You can stick them on the top or sides of the translucent keycaps. Last but not least, we’ll be publishing various video tutorials to ensure getting started is easy.
I2C stands for Inter-Integrated Circuit, pronounced eye-squared-C, and alternatively known as IIC. It is a synchronous, multi-controller/multi-target (controller/target), packet switched, single-ended, serial communication bus. This protocol is suitable for devices wired at short distances, no more than 2-3m. We use I2C in pretty much all our open source products: Internet of Things, mechanical keyboards and Raspberry Pi HATs.
I2C was originally developed in 1982 by Philips. While that makes it 40 years old, it is still a very convenient and widely used bus. There are many I2C sensors and peripherals. It is in pretty much every smartphone, embedded electronics, microcontroller, personal computer and of course Raspberry Pi.
Actually, since the introduction of the famous 40-pin header in 2014, Raspberry Pi single board computers have not one but two I2C buses! We use them both on ANAVI Info uHAT and our other HATs. Th first I2C bus is on pins 3 and 5. On the ANAVI Info uHAT, it is used for the three I2C slots for sensors and the 4th dedicated slot for the mini OLED display.
The second I2C bus is on pins 27 and 28 of the Raspberry Pi and is reserved exclusively for attaching an ID EEPROM. The ID EEPROM contains a software description of the hardware so the operating system on your Raspberry Pi can automatically identify the add-on board.
The I2C bus consists of two signals: SDA (Serial Data) is a data signal, SCL (Serial Clock) is a clock signal. I2C modules also need power, so the dedicated I2C connectors on the ANAVI Info uHAT and our other open source hardware provide two additional pins for VCC and GND. Typically, the VCC for the I2C connectors on our add-on boards for Raspberry Pi are 3.3V.
The I2C bus drivers are “open drain”, which means they can only pull the corresponding signal line at low level. They cannot drive it high. To restore the signal to high when no device is asserting it low, a pull-up resistor has to be added to each signal line. For example, on the ANAVI Info uHAT, we have 4.7K pull-up resistors R4 and R5 connected to SDA and SCL.
Resistor selection varies depending on the devices attached to the bus. In some specific use cases, further adjustment of the resistance value might be required. For systems with lots of devices or longer wires, smaller resistors are better.
How to Enable I2C on Raspberry Pi OS
Raspberry Pi OS, previously known as Raspbian, is the default and recommended Linux distribution for all models and versions of the Raspberry Pi single board computer. By default, I2C is not enabled. There are several ways to enable it, but probably the easiest is using the command-line tool raspi-config to perform few basic commands:
Open a terminal or login remotely via SSH to your Raspberry Pi and type in the following command: sudo raspi-config
Each I2C device must have a unique address. The I2C reference design has a 7-bit address space, although rarely it might be used with a 10-bit extension. The 7-bit addresses range from 0 to 127 (0 to 0x7F hexadecimal). This is a limitation because it is not possible to have two I2C devices with the same address on the same I2C bus. For example, the I2C address on the mini OLED display included in all ANAVI Info uHAT kits is 0x3C. From the software side, this address is used in the example Python 3 script to access the display.
For Linux distributions, including Raspberry Pi OS, there is a package with a heterogeneous set of I2C tools called i2c-tools. To install it on Raspberry Pi OS, open a terminal and execute: sudo apt install -y i2c-tools. Once you have it installed, you can list attached I2C devices by their addresses with i2cdetect. For example, if the HTU21 temperature and humidity sensor module is attached to the Raspberry Pi, the output will be:
OSHWA runs the certification program ensures that the definition of “open source hardware” used by a specific project matches the community’s definition of open source hardware. They provide a unique indentification (UID) for each version of the certified hardware based on the country code and a serial number. For example, the UID for ANAVI Info uHAT is BG000081. The prefix BG is the country code for Bulgaria, because the Info uHAT is made in my hometown of Plovdiv. The serial numbers show that now there are 81 open source hardware devices from Bulgaria.
MH-Z19B is an intelligent infrared CO2 module which interacts with the Raspberry Pi using UART (universal asynchronous receiver-transmitter). Takuya uses the UART port on ANAVI Infrared pHAT to attach MH-Z19B. The rest of the sensor modules for his setup are included in ANAVI Infrared pHAT Advanced kit: HTU21D for temperature and humidity, BMP180 for barometric pressure and BH1750 for light.
By the way, initially we had published open source examples for using HTU21D, BMP180 and BH1750 in the C programming languages using the library wiringpi. Takuya also based his setup on wiringpi. However, wiringpi is now deprecated therefore we have replaced it with another library called libi2c-dev. Furthermore we added examples written in Python 3.