Temperature Sensor PCB Board Project: From Prototype to Mass Production

The temperature sensor PCB project is a successful case from one of our Argentina-based customers. This collaboration showcases not only our one-stop PCBA manufacturing capabilities but also highlights how professional engineering support, careful quality control, and customer-centric optimization can lead to long-term production cooperation. After the initial batch of 2,500 pieces in 2023, the customer returned in 2024 with a larger order of 3,000 pieces, confirming their trust in our quality and service.

Project Overview

PCB Specifications

The temperature sensor PCB was designed by the customer, and we were responsible for the full manufacturing and assembly process. Below are the detailed technical specifications of the PCB:

• Material: FR4 (TG130)

• Board Type: 2-layer

• Board Thickness: 1.6mm

• Copper Thickness: 1oz

• Surface Finish: Lead-free HASL

• Solder Mask: Green

• Silkscreen: White

• Board Dimensions: 60mm x 40mm

• Panelization: 3 pieces per panel using V-cut

• Assembly Type: Single-sided, with both SMD and DIP components

There were no complex trace spacings or critical pad widths, which allowed for efficient board fabrication. After assembly, the PCBs were de-panelized, edge-ground, cleaned, and securely packaged before shipping.

BOM and Component Selection

Precise Component Verification

The Bill of Materials (BOM) contained 15 different component types. The customer provided a BOM with many specific notes and revisions, which required us to:

• Verify each component's package, value, and part number

• Confirm tolerances, e.g., 1% resistors instead of 5%

• Validate any allowed replacements with the customer

Engineering Optimization

Our engineering team carefully reviewed datasheets and specifications for each component. We successfully identified cost-effective alternative parts for several items including:

• Connectors

• Diodes

• Capacitors

• Resistors

By replacing some connectors with more economical options (while ensuring they met all electrical and mechanical requirements), we helped the customer significantly reduce costs.

Assembly and Production Notes

Critical Soldering Issue Solved

A challenging aspect of this project was the placement of component CN1. Positioned at the PCB edge, it presented soldering issues due to:

• Small pad size

• Large pin dimensions

• Tight tolerance between silkscreen and pad positions

To resolve this, our engineers suggested increasing pad size by 1–2mm, and after this design adjustment, soldering quality improved to 100% pass rate.

Testing and Quality Assurance

Functional Testing Process

One of the most important steps in our workflow is PCB functional testing, ensuring each unit operates exactly as expected before shipment.

The customer provided a comprehensive test procedure in PDF format, which included the following steps:

1. Prepare test items:

   • 4 LEDs

   • 1 switch

   • 12V DC power supply

2. Testing actions:

   • Step 1: Turn on the switch → LED1 lights up immediately, then LED2 lights up after 0.5s.

   • Step 2: Touch the temperature sensor → if temperature rises above 30°C, LED3 and LED4 light up.

   • Step 3: Remove finger → when temperature drops below 26°C, LED3 and LED4 turn off.

Overcoming Environmental Challenges

During initial testing, the expected LED behavior did not occur. After troubleshooting, we realized that ambient temperature fluctuations were affecting the readings. By adjusting the testing environment to maintain a precise temperature differential, the issue was resolved, and we successfully tested all 2,500 boards with consistent and accurate results.

About Temperature Sensors

What Is a Temperature Sensor?

A temperature sensor is a transducer that measures temperature and converts the value into an electrical signal. This project used a touch-type sensor, meaning it detects temperature via physical contact.

Principle of Operation

The sensor operates based on thermal conduction or convection, achieving thermal equilibrium with the object being measured. Once equilibrium is reached, the output signal corresponds directly to the temperature of the object.

Application and Industry Use

Temperature sensors are widely used in:

• Industrial automation

• Agricultural control systems

• Consumer electronics

• Medical devices

• Food safety monitoring

• Aerospace and defense applications

• Superconducting and cryogenic research

The versatility and reliability of temperature sensors make them indispensable in modern technology.

This project is a great example of how close collaboration, technical expertise, and manufacturing efficiency can deliver results that exceed customer expectations. From PCB fabrication and assembly to testing and shipping, we supported the entire lifecycle of the product.

If you're looking for a professional PCBA partner who can handle both small-scale prototyping and large-volume manufacturing with engineering insight and strict quality assurance, we’re here to help.