[An old project I moved from my previous website]

This is a test project built hastily on a solder less breadboard. It uses a LM75 to read the current temperature via I2C and displays the result on three 7 segment displays. It uses a PIC16F628 with an internal 4 Mhz clock.

The program was created using JAL

Note the LM75 is a surface mount device, so I had to solder wires onto it to use it on the solderless breadboard.

LM75 Temperature Sensor on breadboard

Sorry for the bad quality photo. The stuff on the left is a 5V voltage regulator and not shown on the schematic below.

LM75 Temperature Sensor Schematic

Component List

Part     Value          Device      Package  Library        Sheet

D1                      7SEG-CA     7SEG-13  special        1
D2                      7SEG-CA     7SEG-13  special        1
D3                      7SEG-CA     7SEG-13  special        1
IC1      PIC16F628      PIC16F628   DIL18    microchip      1
IC2      LM75           LM75        SOP-8    andre_lm75     1
Q1       BC557C         BC557C      TO92-EBC transistor-pnp 1
Q2       BC557C         BC557C      TO92-EBC transistor-pnp 1
Q3       BC557C         BC557C      TO92-EBC transistor-pnp 1
R1       12K            R-EU_0207/7 0207/7   rcl            1
R2       12K            R-EU_0207/7 0207/7   rcl            1
R3       1K             R-EU_0207/7 0207/7   rcl            1
R4       1K             R-EU_0207/7 0207/7   rcl            1
R5       1K             R-EU_0207/7 0207/7   rcl            1
R7       220            R-EU_0207/7 0207/7   rcl            1
R8       220            R-EU_0207/7 0207/7   rcl            1
R9       220            R-EU_0207/7 0207/7   rcl            1
R10      220            R-EU_0207/7 0207/7   rcl            1
R11      220            R-EU_0207/7 0207/7   rcl            1
R12      220            R-EU_0207/7 0207/7   rcl            1
R13      220            R-EU_0207/7 0207/7   rcl            1
R14      220            R-EU_0207/7 0207/7   rcl            1

In case you are like me and couldn’t find the pinouts for the sevent segment display, here they are:

7 Segment Display Pinout

Download the project here: LM75 Temperature Sensor Project - LM75 Temperature Sensor with 7 segment display output. Uses a PIC Controller. This project includes the JAL source code, a compiled hex file and a schematic.