An electronic cattle scale with precision instrumentation, EMI/EMC immunity and an embedded architecture that later evolved to Linux.

The project started with a very concrete problem: the hardware of a cattle weighing indicator had run into trouble during INMETRO testing (Brazil’s metrology authority) and had to be redesigned in roughly 60 days.

The client’s team knew the application software well, but needed support on the hardware side. ECK worked alongside that team, not only developing the new electronics but also transferring knowledge on instrumentation, signal acquisition and techniques to reduce electromagnetic interference.

Electronic cattle scale: redoing the hardware in 60 days

Weighing cattle has an extra difficulty: the animal does not stand still on the scale. The load cell signal has to be acquired and processed so that a stable reading is obtained despite the variations caused by the animal moving.

At the same time, the new hardware had to fix the problems found in the previous version and meet the requirements for approval.

The work covered a review of the electronic architecture, replacement of the A/D converter, design of the input filters, review of the power supply and protections, EMI/EMC treatment and specific care with grounding, analog signals and PCB layout.

The new solution was based on an ARM microcontroller running bare-metal C firmware, with no operating system.

The device was subsequently approved and became a commercially successful product.

Second stage: from thousands to almost one million records

As use of the device grew, a need appeared that did not exist in the original project: a significant increase in storage capacity for weighing records.

At that point, simply adding memory to the original architecture was no longer the right answer.

ECK then took part in a second evolution of the product, using a Toradex module running Linux. This platform made it possible to add an SQL database and raise capacity to the order of one million records.

However, Linux was not the right platform to directly run the critical part of the weighing acquisition.

So the architecture was split into two levels: a dedicated ARM processor remained responsible for acquisition and fast filtering of the scale signals, while the Toradex Linux module handled the higher-level functions and the database.

Two architectures for two different problems

This project ended up with two very distinct generations. The first delivered a robust electronic cattle scale for field use; the second expanded processing and storage capacity without compromising the critical weighing acquisition.

The first had to quickly solve hardware, accuracy and electromagnetic compatibility problems and reach a solution able to pass the applicable tests.

The second had to cope with the growth of the product and a volume of data far larger than originally planned.

Instead of trying to make a single platform do everything, each task stayed where it made the most sense: real-time acquisition on the microcontroller; Linux and SQL for high-level processing and storage.

The case shows how weighing equipment can evolve without abandoning the architecture that guarantees stable, accurate measurement. When storage, interface and processing requirements grew, the solution was to separate responsibilities rather than concentrate everything on one platform.

See other electronic engineering projects developed by ECK.