Smart Radar With Evive, Ultrasonic Sensor & Adafruit IO

Use the actual project photo showing the HC-SR04 ultrasonic sensor mounted on the servo/Evive setup, rather than the circuit diagram. The close-up project photo you provided is the better cover image because it immediately shows the main hardware.

The goal of this project is to create a simple and affordable radar-like scanning system.

Instead of using a traditional radar module, this project uses an ultrasonic sensor mounted on a servo motor. As the servo rotates, the ultrasonic sensor scans different directions and measures the distance of objects.

Evive processes the readings and displays:

Object detection status

Scanning angle

Object distance

The project also connects to Adafruit IO, allowing the detected information to be transmitted for remote monitoring and analysis.

This makes the project useful for learning about robotics, sensors, automation, IoT, and real-time data visualization.

Components and Software

Hardware

1. Evive
2. HC-SR04 Ultrasonic Sensor
3. Servo Motor
4. Jumper wires
5. Mounting/support structure for the ultrasonic sensor

Software

1. PictoBlox
2. PictoBlox IoT Extension
3. Adafruit IO

Working Principle

The radar works through four main stages:

1. Scan

The servo motor rotates the ultrasonic sensor through different angles.

2. Measure

The HC-SR04 ultrasonic sensor sends an ultrasonic pulse and measures the returning echo to determine the distance of an object.

3. Detect

Evive compares the measured distance with a predefined detection threshold.

In this project, an object is treated as detected when the measured distance is below 40 cm.

4. Display and Monitor

When an object is detected, the Evive display changes to a red indication and displays the angle and distance.

The detected information is also sent to an Adafruit IO feed named Radar.

Mounting the Ultrasonic Sensor

First, mount the HC-SR04 ultrasonic sensor on the servo motor.

The sensor should be fixed firmly so that it rotates together with the servo.

Make sure:

1. The sensor is securely attached to the servo.
2. The servo can rotate freely.
3. The ultrasonic sensor faces forward.
4. The wires do not interfere with servo movement.

The servo allows the ultrasonic sensor to scan different directions instead of measuring only one fixed direction.

Circuit Connections

Connect the HC-SR04 ultrasonic sensor and servo motor to the Evive board according to the circuit diagram.

The ultrasonic sensor uses:

1. TRIG → Digital Pin 9
2. ECHO → Digital Pin 8

These pin assignments are also used directly in the PictoBlox project code.

Connect the servo motor to the Evive servo connection used by the project.

Make sure the power and ground connections are secure before switching on the system.

Important: Check all connections before powering the Evive board.

Programming the Evive

The project is programmed using PictoBlox block coding.

Open PictoBlox and select the Evive board.

The program uses:

1. Ultrasonic sensor blocks
2. Servo control blocks
3. Evive display blocks
4. Variables
5. Conditional statements
6. Loops
7. IoT blocks for Adafruit IO

Upload the project to Evive and verify that the board is communicating correctly.

Servo Scanning

A variable called angle is used to control the servo position.

The program starts the angle at 15 degrees.

The servo then moves forward in small increments until it reaches approximately 165 degrees.

After reaching the end of the scanning range, the servo moves back in the opposite direction.

This creates a continuous back-and-forth scanning motion.

The scanning process allows the ultrasonic sensor to measure objects at different angles.

The servo control section of the project uses repeated loops and changes the angle variable by +1 during the forward scan and -1 during the return scan.

Object Detection

During every scanning position, the ultrasonic sensor measures the distance of the object in front of it.

The program checks whether:

Distance < 40 cm

If this condition is true, an object is considered detected.

When an object is detected:

1. The Evive display changes to red.
2. The current angle is displayed.
3. The measured distance is displayed.
4. Object information is sent to Adafruit IO.

If an object is not detected within the defined threshold, the display changes back to the normal indication.

Displaying Angle and Distance

When an object is detected, the Evive display shows the scanning information.

The display presents:

Angle – [current angle]

Distance – [measured distance]

This makes it possible to understand not only how far away the object is, but also the approximate direction in which it was detected.

The display provides a simple real-time interface without requiring an external computer screen.

Setting Up Adafruit IO

To enable IoT-based monitoring, an Adafruit IO account is required.

1. Create an account on Adafruit IO.
2. Open the Adafruit IO dashboard.
3. Create a new feed.
4. Name the feed Radar.
5. Open the API Key section.
6. Copy your Adafruit IO username and API key.
7. Add the credentials to the IoT connection block in PictoBlox.

Security Note: Never publish your personal Adafruit IO API key in a public project. Use your own credentials when running this project.

Connecting PictoBlox to Adafruit IO

Add the IoT extension in PictoBlox and use the Adafruit IO connection block.

Enter:

Username: Your Adafruit IO username

API Key: Your Adafruit IO API key

After the connection is established, the program sends radar detection information to the Radar feed.

The data includes the detected angle and distance.

This allows the sensor information to be monitored remotely through Adafruit IO.

Data Transmission

When an object is detected, the program creates a message containing:

Object detected at: Angle – [angle] and Distance – [distance]

This information is sent to the Adafruit IO Radar feed.

The program then waits for approximately one second before continuing with the next transmission.

This provides a simple IoT-based record of detected objects during operation.

1. Select the correct Evive board.
2. Check the ultrasonic sensor connections.
3. Check the servo connection.
4. Enter your own Adafruit IO username.
5. Enter your own Adafruit IO API key.
6. Confirm that the feed name is Radar.
7. Upload/run the program.

Testing

After completing the hardware connections and uploading the program, switch on the Evive board.

The servo should begin scanning from one side to the other.

Place an object in front of the ultrasonic sensor.

When the object enters the detection range:

1. The ultrasonic sensor measures its distance.
2. Evive identifies the object.
3. The display changes to red.
4. The angle is displayed.
5. The distance is displayed.
6. The detection information is sent to Adafruit IO.

Move the object to different positions and observe how the angle and distance values change.

Results

The completed radar system successfully detected objects and displayed their distance and angle on the Evive screen.

According to the project testing documented for this build, the system detected objects within a range of 0–250 cm with an average reported accuracy of 98.5%.

The servo motor and ultrasonic sensor provided angular scanning and distance measurement, while Adafruit IO enabled remote data visualization and monitoring.

The system was also tested under different environmental conditions, including changes in lighting and temperature.

These results demonstrate the potential of combining low-cost maker hardware with IoT technology to create an interactive radar-like detection system.

Challenges Faced

One of the challenges during development was integrating the project with Processing IDE for external radar visualization.

The Processing IDE could not be successfully interfaced with the PictoBlox block-coding environment used in this project.

To overcome this limitation, the project was modified to use the built-in Evive display along with Adafruit IO for visualization and remote monitoring.

This approach allowed the project to remain functional while also providing a way to monitor the detected data.

Future Improvements

This project can be further improved in several ways.

1. Longer Detection Range

The system could be optimized to improve sensitivity and increase the detection range.

2. Smaller Object Detection

Additional sensor processing could be used to improve the detection of smaller objects.

3. Camera Integration

A camera could be added to provide visual information about detected objects.

4. Infrared Sensors

Additional infrared sensors could be integrated for improved object detection.

5. Object Recognition

Future versions could combine the radar system with computer vision to identify different types of objects.

6. Advanced Data Visualization

A dedicated dashboard could be developed to display the scanning angle, distance, and historical detection data in a more visual format.

Possible Applications

This project can be used as an educational demonstration of:

1. Robotics
2. Ultrasonic sensing
3. Servo motor control
4. IoT
5. Real-time monitoring
6. Distance measurement
7. Object detection
8. Embedded systems
9. Block-based programming

The same concept can be extended to applications such as obstacle detection, smart parking demonstrations, robotic navigation, security systems, and educational STEM projects.

Conclusion

The Smart Radar project demonstrates how an Evive board, ultrasonic sensor, servo motor, PictoBlox, and Adafruit IO can be combined to create a compact radar-like object detection system.

The rotating servo allows the ultrasonic sensor to scan different directions, while Evive processes the sensor data and provides immediate visual feedback.

The addition of Adafruit IO extends the project beyond local detection by enabling remote data monitoring and visualization.

This project provides a practical introduction to robotics, sensor integration, IoT, and real-time data processing using affordable maker technology.

The system can also serve as a foundation for more advanced projects involving object tracking, computer vision, and intelligent navigation.