2. IoT:bit Introduction¶

2.1. Introduction¶

Smarthon IoT Bit is an IoT orientated expansion board for Micro:bit. With the help of this, Micro:bit able to connect to different sensors or actuators without welding and start to use the internet services.

It provides 13 regular GVS socket, allow user to connect batch of sensors at the same time to receive group of data. For some special purpose sensors/actuator, such distance sensor, motor and OLED display, an independent socket are offered, so not only the digital and analog I/O device can use in project, but also I2C device become an option to the Micro:bit from now on. Last but not least, a buzzer is built-in on the board to provide sound generation.

It is the most powerful Wi-Fi extension board for micro:bit in the STEM community. The core is using dual core processor ESP32 compared with the ESP8266 which is single core processor. Besides of the basic ThingSpeak and IFTTT Web services, it supports Wide Area Network (WAN) and can be controlled by mobile app, Amazon echo dot and Google home remotely. Also, it supports object to object communication (O to O) in the Internet. It can facilitate the students to learn the communication between the objects.

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2.2. Product Features¶

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The Most powerful IoT chip ESP32 embedded for micro:bit
Exchangeable wireless modular design (ESP8266, ESP32, BLE)
Integrated OLED and Onboard buzzer embedded
Extended I/O port x13, I2C port x2 from Micro:bit with GVS socket
Extended Servo port x3 from ESP module
Various types of power supply (USB, 3.7V lithium battery, 6V Normal battery)
Extra Port: Crocodile Pin, Quick Access Port and 4-Pin Port for different usage

2.3. Hardware Size¶

Product size: 75mm X 65mm X 20mm
PCB thinkness: 1.5mm
Hole diameter: 4mm

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2.4. Specification¶

Item	Parameters	Remarks
Size	75mm X 65mm X 20mm	Without Packing
Power supply	USB:5V Lithium Battery :3.7~4.2V AA Battery*4 :6V	Maximun current limit of whole board: 1A
Operation Temperature	0 to 80℃
Buzzer	Passive Buzzer(Musical)
Wireless Module	ESP8266 ESP32 Bluetooth	Operate under UART protocol
OLED Module	128*64 resolution OLED Screen SSD1306	Operate under I2C protocol
Micro:bit lead out	13 I/O Pins (13 Digital & AnalogOut Pins) (6 AnalogIn Pins)	Reserved Pins: Wireless module:P8,P16 4-Pins module:P12,P13
I2C Pins	P19,P20	3 available ports, 1 port reserved for OLED
ESP lead out	3 Pins for servo control(S1,S2,S3)	Control by ESP chip

2.5. Pinout Information¶

Pinout Diagram:

Port Diagram:

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Pinout Table

Type		Micro:bit	IoT:bit	Extra Port
Analog	P0		Buzzer	Rapid Access Port
	P1			Rapid Access Port
	P2			Rapid Access Port
	P3	LED
	P4	LED
	P10	LED
Digital	P6	LED
	P9	LED
	P12			4-Pin Port
	P13	SPI(SCK)		4-Pin Port
	P14	SPI(MISO)		4-Pin Port
	P15	SPI(MOSI)		4-Pin Port
Serial	P8	UART(TX)	ESP32(RX)
Serial	P16	UART(RX)	ESP32(TX)
I2C	P19	I2C	OLED(SCL)
I2C	P20	I2C	OLED(SDA)
External Servo	S1		ESP32(23)
	S2		ESP32(22)
	S3		ESP32(21)

2.6. Hardware Interface¶

Micro:bit edge connecter
USB Port
Power Switch
3.7V Lithium battery Port [XH2.54]
6V 4*AA(1.5V) battery Port [DC 5.5mm]
Rapid Access Port
Crocodile Pin
I2C Port
4-Pins Port
ESP Servo Port
Buzzer switch
4mm Hole
OLED Module (128*64 pixel)
ESP32 Wireless Module
Buzzer
General GVS Port

2.7. Detail Hardware Description¶

Micro:bit edge connecter

Provide the socket for the Micro:bit to install. Follow the instruction icon right about that to install the Micro:bit to the expansion board.

Power port(USB, Battery, DC) & Switch

Provide three different type of methods to power on the expansion board and Micro:bit. User can either choose common 5V USB power, or two different port which connect to 3.7V ~ 6V battery box.

Wireless Module

The Wireless Module provide the Core function of the expansion board. Though different modules install on the socket, Micro:bit gain the correspond connectivity ability. User may install ESP32, ESP8266, Bluetooth to implement various application project, make use of the IoT resource.

OLED Module

The expansion board have the reserved space to place a SSD1306 0.96 inch OLED screen. User can use the I2C connection port to output the visual element on that module.

ESP Servo port

When installed the ESP32 module, it provide extra 3 servo control port to connect the Servo motor. Compatible with general GVS 180/360 Servo motor (SG90/SG90S)

Buzzer & Switch

The IoT Bit built in a Passive Buzzer on the board, which connected to P0. Using the program can generate different tone of sound.
Since each I/O pin should be only serve for one sensor/actuators at the same time, so you should pulling the switch down (to the sound icon) when using buzzer, otherwise pulling the switch up (to the mute icon) to avoid the interrupt from buzzer to P0.

Micro:bit lead out Pins

The Lead Out from the Micro:bit I/O pins, provide great expansion feature for the Micro:bit , user can connect up to 13 different sensor/actuator at the same time. Each independent GVS socket make the connection become more connivance.

4-Pins Module Port

On the IoT Bit, two ports are reserved for the 4 Pins Module. Each port can connect to some sensors or actuators which required use two I/O Pins at the same time, such Distance Sesnor. In total, there are 4 I/O Pins being used, they are P12, P13, P14, P15 respectively.

I2C Port

Since Micro:bit support I2C protocol, IoT:bit provide three I2C port (one reserved for OLED Module) to connect I2C peripherals, make the IoT project can access more sensors/actuators.

Rapid Access Port

To some GVS sensor which provide the Rapid Insert Pin, it can use on the Rapid Access Port. It do not need to use the cable to connect the sensor, simplify the product in the application.

Crocodile Pin

For the user who use the crocodile cable clips to connect parts, Iot Bit reserved 5 Pins for them to get easier access. There are 3 Pins from GVS Port 0,1,2 and 2 Pins for 3V and Ground.

2.8. Software Support¶

MakeCode editor

The MakeCode editor is the official cross-platform editor designed for BBC Micro:bit, it is available on Web Browser, Mobile and tablets Apps. The Colorful coding block is familiar to who previously used Scratch, providing a simple and clear way to programming on the Micro:bit.

The editor offer a text-based mode for user to programming using JavaScript rather than drag the blocks
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Python editor

Python is one of the most famous programming language, widely used in school and industry. Micro:bit provided an online python editor for user to study and exercise python on Micro:bit. User just need to connect Micro:bit with USB and click the Flash button, the compile and upload progress will be finish automatically.
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