DIY Digital Clock with Temperature Display using PIC Controller

One of the most enjoyable part of being an electronics person is creating your own gadgets and using them in daily life. In this article, we are building one of those with the help of SoloPCB design tools, a digital desk clock with temperature display feature.

DIY Digital Clock with Temperature Display using PIC Controller

The brain of the circuit is a Microchip PIC18F252 microcontroller. It acquires precise time information from DS1307 real time clock via I2C interface and displays it on four digit 38 mm seven-segment display with the help of MAX7219CNG display driver. The temperature data is read by the on-chip ADC module of the microcontroller from LM335 temperature sensor which outputs 10mV per kelvin degree linearly. The temperature data is also displayed periodically.

The PIC microcontroller and the peripheral ICs mentioned above needs 5V regulated supply to operate. The step-down converter in the power section of the circuit, LM2574N-5.0, converts 12VDC input voltage to 5VDC and lets to draw 500mA without any significant heating problem.

There are two LEDs on the board indicates power and functional status and the buttons let the user adjust the time and display the temperature manually.

The Circuit and the PCB Design

The circuit and the PCB of the project are drawn in SoloPCB. SoloPCB is a very powerful tool which integrates the circuit design to the PCB design and the fabrication. You can download SoloPCB from FabsSream for free. The circuit and the PCB files of the project are provided in SoloPCB format. You can download the design files including the symbol and the footprint libraries by using the download link below.

READ  Analog & Digital propeller clock using PIC16C84

The circuit schematic of the digital desk clock and a screenshot from its PCB can be seen below.

After the PCBs fabrication, the components listed below are assembled on the board.

Bill of Materials:

Quantity Part Description Designator
1 CR2032 Battery Holder B1
1 22uF 16V Tantalum Capacitor C1
1 10uF 16V Electrolytic Capacitor C10
1 220uF 16V Electrolytic Capacitor C2
5 100nf 63V Ceramic Capacitor C3 C6 C7 C8 C9
2 22pF 50V Ceramic Capacitor C4 C5
1 MBR-150 1A 50V Schottky Diode D1
1 3mm Red LED D2
1 3mm Green LED D4
1 LM335 Temperature Sensor D3
1 BAT42 200mA 30V Schottky Diode D5
1 DC-001 Power Connector J1
1 1×5 2.54mm Male Header J2
1 2×4 2.54mm Male Header J3
1 150uH 850mA Inductor L1
4 38mm Common Anode 7 Segment Display LD1 LD2 LD3 LD4
3 330R 1/4W Resistor R1 R2 R11
6 10K 1/4W Resistor R3 R4 R5 R7 R8 R10
1 2K 1/4W Resistor R6
1 27K 1/4W Resistor R9
3 SPST-NO 6mmx3.5mm Tactile Switch SW1 SW2 SW3
1 LM2574N-5.0 0.5A Step-Down Converter U1
1 PIC18F252-I/SP Microcontroller U2
1 28 Pin DIP Socket 300mil U2 Socket
1 MAX7219CNG 8 Digit Display Driver U3
1 DS1307+ Real Time Clock U4
1 32.768KHz Crystal Y1
1 10Mhz Crystal Y2


All the components are through hole type so there is no need for a very good soldering skill.


Read More:    DIY Digital Clock with Temperature Display using PIC Controller

Current Project / Post can also be found using:

  • temperature display project books

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