The Kilo Lamp: An Interactive Lamp Controller

The Kilo Lamp is an interactive lamp controller built using an Arduino Uno shield. It also contains a load cell, a load cell amplifier, and a MOSFET that drives an LED using a pulse-width modulated (PWM) signal. The brightness of the LED is determined by how much weight is placed on the lamp. When the load reaches 5 kg, the lamp achieves 100% brightness. Figure 1 shows the fully assembled Kilo Lamp shield.

Figure 1. The Kilo Lamp shield.

Specs and Operation

• Supply: 12 V DC.
• Onboard Load Cell Amplifier: HX711.
• Onboard MOSFET: PWM LED Driver.
• Load Current: Up to 1 A.
• PCB Dimensions: 51.44 x 41.75 mm.

The load cell sends an analog signal to the HX711 load cell amplifier. The HX711 acts as an analog-to-digital converter (ADC) and outputs a digital signal. This signal is read by the Arduino Uno, which processes the weight data and generates a corresponding PWM signal. The PWM signal is then fed into a MOSFET, which drives the LED and adjusts its brightness according to the PWM duty cycle, directly proportional to the applied weight. In simple terms, the greater the weight, the higher the light intensity.

Schematic and Bill of Materials

Figure 2 provides the schematic for this project. You can view a higher-resolution version of the schematic by clicking on the image.

Figure 2. [click to enlarge] Schematic for the Kilo Lamp.

The bill of materials for the Kilo Lamp is shown in Table 1.

Table 1. BOM for the Kilo Lamp.

Wiring Instructions

To wire up the Kilo Lamp, consult the diagram in Figure 3 and the information below it.

Figure 3. [click to enlarge] How to connect up the Kilo Lamp. Image of load cell (left) used courtesy of SparkFun Electronics; Image of LEDs (right) used courtesy of ThinkRobotics

Referring back to the schematic in Figure 2, the wiring connections are as follows:

• CN1
  • Pin 1 = Load Cell Red Wire.
  • Pin 2 = Load Cell Green Wire.
  • Pin 3 = Load Cell White Wire.
  • Pin 4 = No Use.
  • Pin 5 = No Use.
  • Pin 6 = GND.
• CN2: Do Not Install.
• CN5: Jumper for single supply operations.
  • Arduino Uno V_in and Shield 12 V.
• CN3:
  • Pin 1 = VDD 12 V.
  • Pin 2 = LED Cathode.
• CN4:
  • Pin 1 = GND.
  • Pin 2 = 12 V DC Input.
• D1: Power LED.

PCB Files and Arduino Code

To download the Gerber files for the Kilo Lamp, click on the button below.

Kilo Lamp Gerber Files

The Arduino code for the project is also available for download here:

Kilo Lamp Arduino Code

Upload this code to the Arduino Uno and install the shield (Figure 4) to see the magic!

Figure 4. The completed Kilo Lamp project with the shield installed.

All images used courtesy of Rajkumar Sharma except where otherwise specified