Arduino Scale (SmartScale)

Hi! Welcome to SmartScale its Instructables page.

This Instructables guide is for anyone interested in building a smart, compact, and efficient scale. This scale can weigh up to a maximum of 20kg and is perfect for shops, individuals, and anyone looking for a portable and easy-to-use weighing solution.

Used materials:

• HX711 + loadcell

• Buzzer

• OLED 0.91"

• Ultrasonic sensor

• Pushbutton

• MPU6050

In the images shown above, you can see the breadbord scheme and the electric circuit. It has all been verified by our electronic teacher, so everything should work fine!

This is how the DB is made:

Table 1: Device

• DeviceId (PK)
• Name
• Type (sensor / actuator)

Table 2: History

• HistoryId (PK)
• DeviceId (FK to Device)
• ActionId (FK to Actions)
• ActionDate
• Value

Table 3: User profile

• Id (PK)
• Name
• Email
• Password

Table 4: Weighing measurements

• MeasurementId (PK)
• MeasuredWeight
• TareSetting
• Ambient temperature
• EffectiveWeight
• DeviceId (FK to Device)
• User ProfileId (FK to User Profile)

Table 5: Actions

• ActionId (PK)
• Status (on / off)
• User ProfileId (datetime)
• DeviceId (FK to Device)

The images you see here, show how most cables, components, and so on are placed on the breadbord and connected with GPIO pins. You can easily verify with these images and the breadbord scheme in the step before this one, to verify if you're doing everything correctly.

Here you can see my 3D sketch made that I've made in Blender. For me, it was an easy-to-use program as I've never did any 3D-modelling before. If you're new to this too, I really recommend this.

Length: 20 cm

Width: 12cm

Height (with HX711 loadcell): +- 9 cm

As shown on the images, you'll have to print the base and the round weigh plate seperatly, as you'll have to attach the HX711 loadcell in between the base and the round weigh plate. Ensure you have enough supports too!

In this step, you see the full built from the SmartScale. It shows all different sides of how eveything has been attached, plugged and so on. As seen on picture 4, I've added a small extra breadbord because the standard doesn't fit well with the HX711 module.

The HX711 loadcell, ultrasone sensor, pushbutton and OLEd screen have been attached with hot glue to avoid falling out the 3D object.

To make this project, you also need some frontend / backend code. This SmartScale project is made with: Python, HTML, CSS, JavaScript.

All the code can be found on GitHub: https://github.com/howest-mct/2023-2024-projectone-mct-BoelensVince.git

If you've done all the steps mentioned above, the SmartScale must be working fine!

Ensure that all connections are well attached in for example the breadbord or the component, that you've got the correct sensors and also enable the correct busses (i²c and so on) in your Raspberry Pi. Also see that the VCC and GND are correctly switched into the components.

By any issues, you can always contact me!

-- Founder of SmartScale.