PIC Dual-channel Thermometer

DS18S20 Dual Thermometer Component List:

1x2x16 Backlit LCD Monitor

1x16x1 LCD Monitor Female Connector

1x16x1 LCD Monitor Male Connector

1x Programmed PIC16F628

2x DS18S20 single-wire digital temperature sensors

1 x 100nF capacitor

1 x 10K potentiometer (LCD contrast ratio)

1 x 10K resistor

2 x 1K resistors

1x10 resistors

1 x LM7805 voltage regulator

1x Haptic Switch (Display Mode)

1x 2-pin male connector

1 x 4-pin male connector

Technical Specifications:

Temperature measurement range: -55 to 125°C (-67 to 257°F)

Accuracy: 0.5 °C / 1 °F

Power supply voltage: 7.5 - 15V

Power consumption: 8mA (when the LCD backlight is off)

DS18S20 Dual Thermometer

This is an easy-to-build DS18S20 dual thermometer that can simultaneously measure the temperature at two different locations. Thanks to the use of a PIC16F628 microcontroller and a 2x16 character LCD display, the instrument is built with very few components. It's like a small computer that can be customized by upgrading its hexadecimal firmware.

The DS18S20 dual thermometer uses two very exciting DS18S20 digital temperature sensors in a convenient TO92 package. Unlike conventional sensors that transmit temperature readings by varying voltage, the DS18S20 transmits temperature information as data in digital format. This opens up many new possibilities and allows temperature information to be transmitted over longer distances using only two wires. With this capability, temperature can be measured simultaneously at different locations far from the main board. For conventional voltage-dependent temperature sensors, the wires must be as short as possible, as longer wire lengths introduce stray resistance and lead to unreliable readings.

Another great feature of the DS18S20 sensor is that it requires absolutely no calibration while providing 100% accuracy. This means you simply plug it in and don't need to spend time recalibrating temperature readings. This is all thanks to its ability to send information in digital format. In fact, the DS18S20 is like a computer connected to a network, with a unique serial number identifier similar to an IP address. Multiple DS18S20 sensors can send information simultaneously, even through the same two-wire bus cable. These two wires provide 3-5V power to the sensor and are also used for bidirectional data transmission. If the wires are so long that the voltage on the DS18S20 sensor drops below 3V, the sensor can be powered using an external 5V power supply and a 1K resistor.

Once the PIC microcontroller receives the temperature information, it converts it to Celsius and Fahrenheit values ​​for display on the LCD screen. The DS18S20 dual thermometer can measure temperatures from -55 to 125°C (-67 to 257°F) with an accuracy of 0.5°C / 1°F. If you only need to measure the temperature at one location, you can use only one DS18S20 sensor, and the PIC16F628 microcontroller will use only one sensor.

Customized DS18S20 Dual Thermometer

Furthermore, the temperature display on the LCD screen can be customized by pressing a tactile button. Each selection is stored in non-volatile EEPROM memory, so the PIC remembers it even after power is off. Requests for different display styles are welcome, and upgrades can be made by simply flashing the PIC16F628 microcontroller with new hexadecimal firmware. We also plan to release a temperature thermostat version in the near future, which will turn the device on/off when a specific temperature is reached. The thermostat can be used to turn heaters, fans, air conditioning systems, etc. on/off.

DS18S20 Dual Thermometer PCB Layout

DS18S20 Dual Thermometer Kit