Tablet Tester

Project Description

Requirements
This product was designed for a leading asian pharmaceutical equipment manufacturer. The product measures the dimensions and hardness of a medical tablet with high precision. The client wanted a very low cost product to target the large east Asian markets. The product had to be robust and easy to manufacture with low inventories. Test throughput was a major consideration.

Solution
Medical Tablet tester PCB A 32 MIPS architecture processor was chosen for this product. The single processor system has to control and drive a stepper motor at varying speeds, run multiple ADC conversions, execute a couple of complex digital filtering algorithms and manage a simpler user interface. Configuration was stored in a serial EEPROM. The peripherals were connected through I2C buses. All electronic components were SMD devices and the PCB had four layers.

The firmware was developed in C programming language with parts of it in assembly. A custom cooperative multitasking scheduler was used to manage the various time bound tasks. A remote control command set allowed the instrument to be controlled by PC software via RS-232 link. The product had to support multiple printers directly, this included both 80 column and 42 column thermal printers. The acquired data of previous tests up to 100 results would have to be stored and retrieved.

Specific digital filtering algorithms were developed for this product, to achieve high precision. Code and process optimizations were done to achieve high throughput.

User interface was designed to allow industry users of these products a quick and familiar to the use the instrument. The entire product was designed and developed on schedule. The development was duration was four months. The design was transitioned to a contract manufacturer. Manufacturing tests were developed to help in quick verification of the manufactured products.

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