Nearly all of our wireless communication is done using radio waves*, including phone calls, text messages, and WiFi. With its built-in radio transmitters and receivers, the Micro:Bit microcontroller makes it super easy to build all sorts of projects with radio communication.

This particular project is a simple & quick way to send text messages between two Micro:Bit** microcontrollers – the sender writes a (short) message that is transmitted via radio to the receiving Micro:Bit, which shakes a lil’ puppet using a servo motor, and then displays the message on the Micro:Bit LED screen. Each Micro:Bit can be both a sender and receiver.

It’s sort of like a two-person Twitter.. if the tweet notified you via dancing cardboard robot puppet!

Step 1: Materials & Tools✍️

Electronics

• Micro:Bit microcontroller (x 2)
• Servo Motor (x 2)
• Alligator Clips to Breadboard Wires

Puppet (or other Message Alert System) Materials

• Cardboard (approx. 2 ft. x 1 ft.)
• Paper Fasteners (13 or more)
• Skewers (5 or more)

Tools

• Hot Glue Gun
• Scissors and/or utility knife (e.g. exacto knife)
• Pencil
• Ruler or other straightedge

Step 2: Build the Incoming Message Alert Puppet!✍️

Step 1: Build a cardboard puppet like the one shown in the photo or create your own! Use the paper fasteners to make joints.

Step 2: Build a mounting system to attach the puppet to the servo with skewers and cardboard.

I used a magnet to attach the puppet to the servo mounting system because magnets are awesome, but you can also use glue, tape, velcro, or a variety of other adhesives!

Step 3: Build a stand for the puppet.

• On an approx. 6 in. x 12 in. cardboard sheet, measure, mark, and cut a hole for the servo body so that the arms of the servo rest against the front of the cardboard sheet.
• Cut two triangles out of cardboard and glue them on the back of the stand so that the stand, well, stands upright!
• Cut a hole for the Micro:Bit wires to thread through and add two pushpins on the front to hold the Micro:Bit.

Step 3: Code the Two Micro:Bits!✍️

To start, choose one Micro:Bit to be the sender and the other Micro:Bit to be the receiver. Once both are working as expected, add in the code for both roles.

Use the Make Code Micro:Bit website to program each Micro:Bit. As this is intended as a beginner project, the whole system can be built using the block-based programming language, although adaptations are encouraged and appreciated!

If there is more than one pair of Micro:Bits in the room (i.e. in a classroom setting), remember to set different radio group numbers for each pair.

The sender sends a (short) text based on user inputs over radio, like the example above. Pretty simple!

The receiver moves the servo when an incoming text is received, then scrolls the message text on the LED screen, like in the example below.

Press the reset button to stop sending/receiving the incoming message.

Step 4: Connect the Servo!✍️

Connect the servo red wire to the Micro:Bit 3V power pin, the servo black wire to Micro:Bit ground pin, and the servo white (or yellow) wire to the Micro:Bit input pin P0.

Step 5: Send All the Messages!✍️

Program both Micro:Bits to be both a sender and a receiver so you can communicate back and forth. Then switch power from the laptop to the battery pack and test out your wireless communication system! When the sender sends a message, the puppet will notify you to check the LED screen so that you can see the incoming message.

How far of a range can you get? Test it out!

There are tons of other extensions to this introductory project, here are some possibilities:

• Add more message options by adding more inputs or changing how those inputs are read;
• Instead of a table-top alert system, build a wearable alert system;
• Send voice messages and/or other sounds.

Special note: The author of the above article is  jenfoxbot , Original shared link：

I have being testing some of the Bluetooth projects of the kit. I used the Makecode environment (as suggested in the manual) instead of Lets code for the having access to the Bluetooth functions/modules. Once the project is created in Makecode environment I download it to a MicroBit V2 which later I insert in the crowbit platform, then the Bluetooth control is done from the Monitor/control area of the Microbit app.

The Bluetooth link and most of the functions work well, I can run the buzzer, LED module and one DC motor module without problems, but when adding a second DC motor (for example for the Bluetooth Car patrol) this motor only runs in one direction. I have tried to exchange the motors, in case one of them will be broken, but the result is the same, so I guess both motor modules are ok. I have also tried to use a different set of pins attached to the DC motor module, e.g. instead of P2/P3, I have tried with P14/P16 but the problem is still there.

The DC motor modules are only working with P0/P1 set of pins, when I select a different pair of pins (needed for a second DC motor) the error is always there (only running in one direction).

Could it be related with some internal use of the direction signal when using Bluetooth applications?

or Could it be related to the use of MakeCode instead of LetsCode? In applications developed with LestCode (no Bluetooth controlled) the 2 DC motor modules work fine.

Is there any way of implementing the Bluetooth examples using LetsCode? It looks from the picture advertisement that you have an specific App for Bluetooh application control. But I could not find it.

If you have a complete example in LetsCode of a Bluetooth project, I would really appreciate to have it.

Let me know any suggestion,

Best regards

The Micro:bit uses a moisture sensor to monitor the moisture level in the plant's soil and then switches on a small pump to water the plant if the soil gets too dry. This way, your plant is always looked after, even when you've forgotten about it or you're away.

✍️Supplies

• MicroBit – Buy Here
• Capacitive Moisture Sensor – Buy Here
• DC Pump – Buy Here
• Relay Module – Buy Here
• Ribbon Cable – Buy Here
• Storage Containers (Not the same, but should work) – Buy Here
• Power Supply – Buy Here
• M3 Screws – Buy Here

I’ve used the MicroBit version 2, but this project can be made using the first version as well.

Step 1: Preparing Your Components✍️

MicroBit is a small programmable micro-controller that has a number of onboard sensors and buttons, making getting started with programming really easy.

You can use block coding for children and less experienced programmers and JavaScript or Python for those who are more experienced with programming and want to get more functionality out of it. It also has a range of IO pins available for sensors and devices along it’s bottom edge.

The capacitive moisture sensor I’m using runs on 3.3V, which is perfect to be used directly with the MicroBit.

Note: These capacitive sensors generally state that they operate between 3.3V and 5V, and output a maximum of 3.3V as they have an onboard voltage regulator. I've found that a lot of the cheaper versions of these sensors don't actually work with an input voltage of 3.3V, but require 3.5-4V before they actually "switch on". You'll need to be careful with this as the Micro:bit is only designed for an input voltage of up to 3.3V.

The pump will need to be turned on and off using a relay module. The relay module switches power to the pump so that the current isn’t flowing through the MicroBit.

Step 2: Designing the Circuit & Code in TinkerCAD✍️

I designed the circuit and did the block coding in TinkerCAD since they’ve recently added the MicroBit to their platform. Block coding is a really easy way to build basic programs by just dragging and dropping function blocks.

I used a DC motor to represent the pump and a potentiometer to simulate the moisture sensor input as it also requires the same three connections.

In my final version of the block code, the Micro:bit shows a smiley face when it’s turned on then starts taking moisture readings every 5 seconds and plotting them on the graph on the display. It also checks whether the moisture level is below the set limit, and if it is then it turns on the pump for 3 seconds. It continues to cycle the pump, with a 5-second break between cycles, until the moisture level is again above the limit.

I also added functions to the two buttons where button A turns the pump on for 3 seconds to manually water the plant, and button B shows the moisture level reading on the display.

Step 3: Testing the Circuit and Code✍️

Once I was happy with the simulation running in TinkerCAD, I connected the components together on my desk to check that they worked in the same way. I made temporary connections using some jumpers and alligator clips to attach to the Micro:bit pins.

This was mainly to test that the Micro:bit was reading the correct values from the sensor and that the relay was able to be turned on and off.

Step 4: Making the Water Tank✍️

Once I was happy with the test setup, I got to work on making a water tank, building the components into a housing, and doing the permanent electrical connections.

I found these two containers in a local discount store. They stack together so that I could use the bottom one as a tank and the top one to house the electronics.

To make the tank, I needed to mount the pump into the tank with the water inlet as close to the bottom as possible, while still leaving enough room for the water to flow. I glued the pump in place using a glue gun.

I then drilled holes for the wires to the motor and the tube for the water outlet.

Step 5: Assemble the Electronics✍️

I wanted the MicroBit to be mounted onto the front of the housing so that it was easy to see, as I’m using the LED display on the front as a graph of the water level.

I drilled some holes through the front to hold the MicroBit and act as the connections to the IO pins on the bottom. I used some long M3 x 20mm button head screws to screw into the terminals on the IO pins and connect to the wiring on the inside of the case. I connected the wiring to the screws by wrapping some of the exposed wiring around the screws and then using heat shrink tubing to hold it in place.

I also drilled holes for the power lead to the Micro:bit, for the power socket at the back and for the pump and moisture sensor wires.

I then connected all of the wiring, soldering the joints, and connected the components together inside the housing.

Step 6: Testing the Watering System✍️

Now that all of the components are assembled, it's time for a bench test.

You can code, customize, and control micro:bit to bring your digital ideas, games, and apps to life. Measuring 4cm by 5cm, and designed to be fun and easy to use, users can create anything using micro:bit, from games and animations to scrolling stories at school, at home, and on the go. All you need is imagination and creativity.

micro:bit v2 has a lot of features and is completely programmable. Each of its LEDs can be individually programmed. It is also equipped with a MEMS microphone, speaker, and touch-sensitive logo. If you want to realize wireless projects, it is equipped with a 2.4GHz micro:bit radio and BLE Bluetooth 5.0. Also, It has 25 red LEDs that can flash messages and two programmable buttons that can be used to control games or pause and skip songs on a playlist. micro:bit v2 can also detect motion and tell you in which direction you’re heading in with the help of the onboard accelerometer.

Feature:

① Pocket-sized microcontroller (4 x 5cm) designed for kids and beginners

② Wireless connectivity with built-in 2.4GHz micro:bit radio and BLE Bluetooth 5.0

③ 25 red LEDs that can be used for interactions

④ Onboard MEMS microphone, speaker, and touch-sensitive logo

⑤ Onboard accelerometer for motion sensing applications

⑥ Notched edge connector for easier connections

⑦ Dedicated I2C bus for peripherals

⑧ Two programmable buttons

Specification:

Processor: Nordic Semiconductor nRF52833

Memory: 512KB Flash, 128KB RAM

Interface: NXP KL27Z, 32KB RAM

Microphone: MEMS microphone and LED indicator

Speaker: On-board speaker

Logo touch: Touch-sensitive logo

Edge Connector: 25 pins. 4 dedicated GPIO, PWM, I2C, SPI and ext.power. 3 ring pins for connecting crocodile clips/banana plugs. Notched for easier connection

I2C: Dedicated I2C bus for peripherals

Wireless: 2.4GHz micro:bit Radio/BLE Bluetooth 5.0

Power: 5V via micro-USB port, 3V via edge connector or battery pack, LED power indicator, Power off (push and hold the power button)

Current available: 200mA available for accessories

Motion Sensor: ST LSM 303

Software: C++, MakeCode, Python, Scratch

Size: 5cm(w) x 4cm(h)

Comparison between the current version (v1.5) and the latest version (v2.0)

The device is described as half the size of a credit card but including an ARM Cortex-M0 processor; An accelerometer that detects the acceleration of the micro:bit and tricks motions like tilt, shake, free fall and etc; Bluetooth and USB connection;25 individually programmable LEDs which allows you to display text, numbers, and pictures through a combination of ON and OFF LEDs; and two programmable buttons. It can be powered by either USB or an external battery pack.Furthermore You can control the external device through 25 pins on the edge connector of the micro:bit.

It is widely used in STEAM education and helping encourage children to get actively involved in writing software for computers and building new things, rather than being consumers of media. You can use your micro:bit to code,customize,and control it from anywhere.More than that,it is available for all kinds of creations whatever it is.As for what you can do with micro:bit, that’s only limited to your imagination. You can program it using Microsoft Blocks, python or JavaScript language.

Features:

① 25 individually-programmable LEDs

② 2 programmable buttons

③ Physical connection pins

④ Light and temperature sensors

⑤ Motion sensors (accelerometer and compass)

⑥ Wireless Communication, via Radio and Bluetooth

⑦ USB interface

If you have any questions about Microbits, please post in this section, we will check and solve the problem in time.

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