Heater Click is designed with intention of PCB heater concept testing and useful tool for heating complete casing where staying in specified temperature range is crucial. Exact PCB temperature can be set and controlled using TMP235 on board temperature sensor from Texas Instruments. Heater Click is useful tool for some projects and products that require some kind of heating, whether to prevent electronics from becoming too cold, to help control humidity, to heat up a substance, or even to prevent one material from sticking to another.

Heater Click board™ is supported by a mikroSDK compliant library, which includes functions that simplify software development.

Heater Click works on a principle of Joule heating, also known as resistance heating (resistive heating), a process by which the passage of an electric current through a conductor produces heat. Energy dissipated per unit time is equal to current passing through resistor times electric potential difference.

Heater Click allows PCB temperature adjusting and monitoring as it have embedded trace resistor on top layer of PCB. Resistor is made from copper 1oz thick and a pattern of 0.1mm wide track 1950mm long, this give us about 10 ohm resistance at 25 degrees Celsius.

With on board VIN SEL jumper power supply can be selected as 5V from mikroBUS™ or any other voltage from external power supply at terminal block VIN. Using mikroBUS™ PWM pin power dissipation can be adjusted and therefore temperature controlled.

Heater Click minimize temperature spread from embedded resistor by having PCB gaps between it and rest of the Click board™ and components, by doing so hot zone is easier to warm up and keeping it at exact temperature without affecting rest of the components. LEDs are connected to LD1 and LD2 GPIO pins and can be used for example to signal user if temperature is ramping up or achieved, or any other user defined signaling.

Since the temperature rise in a heater is a function of its resistance and voltage, you don’t always need to design a heater from scratch. So long as you can apply a specific voltage, you should be able to achieve your desired temperature and monitoring it through I2C.

Temperature is monitored with TMP235 precision CMOS integrated-circuit linear analog temperature sensor with an output voltage proportional to temperature, The TMP235 device provides a positive slope output of 10 mV/°C over the full –40°C to +150°C temperature range. Using MCP3221 a 12-bit ADC, output voltage from temperature sensor can be red through I2C. Communication to the MCP3221 is performed using a 2-wire, I2C compatible interface. Standard (100 kHz) and Fast (400 kHz) I2C modes are available with the device.

• Interface: I²C, PWM
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V or 5V

• Schematic
• TMP235 Datasheet
• mikroSDK
• GitHub