Production Recorder

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This project is about a system that can help supervisors to monitor production in manufacturing stations. Currently, a supervisor relies heavily on the logs created by the personnel which leaves plenty of room for lethargy and inefficiency.  I came to know this through Niranjan, a mechanical engineering friend of mine, who noticed this ‘corruption’ during his implant training. This project is the solution that I came up with.

Most modern manufacturing machines, especially the CNCs, have a stack light or machine status lights to indicate the state of a machine. Typically a stack light will have 3 lights – Red indicating breakdown, Yellow indicating a job in progress and Green indicating that the machine doors can be opened for retrieving or setting the work piece. Therefore the transition from yellow to green indicates the end of a process and at the end of each such process there is a finished workpiece.

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Machine Status lights or Stack lights

The Production Recorder system has multiple transmitters, each associated with a single machine, to communicate with a central receiver. Each transmitter module monitors the stack lights of its associated machine. This is done by using light sensors to detect the light or simple level translators to see the electrical signal supplied to each light. The microcontroller in these transmitter modules is programmed to read the light being ON or OFF as a digital input for processing. At every Yellow to Green transition, the transmitter module’s microcontroller, a MSP430, understands that a job is finished and expects the operator to tell the result of the job. It does so by waiting for one of three buttons to be pressed- the crossed button (bottom) for defective, the dashed button (middle) for minor faults and the clear button (top) for Quality Check Passed. The operator is required to check the workpiece and press one of the three switches on the transmitter module for good, minor fault or defective.

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Every job and its result is reported by the transmitter to a central receiver. The transmitters send specific codes detailing the particular machine number and the quality of the current job to the central receiver via the ‘NRF24L01+’ RF transceivers. If in case the operator does not press any switch and another process starts (when the microcontroller sees Yellow during its wait state) a warning code is sent. In the event of a breakdown and the microcontroller sees the Red light, a breakdown code is sent. These codes are obtained by the central receiver through the same transceiver. The central receiver also has a ‘HC 05’ Bluetooth module to transfer these codes to the supervisors mobile for processing. The central receiver functions as a link between the individual transmitters and the android app.

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The custom built app processes these codes and updates production values on the screen. The codes are used to determine which machine and its current job result to increment the appropriate value on screen.  In case of a breakdown, the machine title gets displayed in a red background to notify the supervisor that something is wrong with the machine.

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Screenshot before establishing Bluetooth Connection through ‘Source Select’

If the machine is repaired and resumes production after a breakdown, depending on the next job result an increment occurs and the title color of the appropriate machine goes back to its normal color. As a proof of concept prototype, the project’s transmitter module microcontroller simulates the stack lights by providing the signals to the LEDs appropriately and then reading that as an input. Practically, the concept and method remain the same.

Future work can be done to take an IoT based approach so that the data can be accessed by any authorized person anywhere anytime. Also, the app can be modified in order to automatically generate a variety of plots using the obtained data for performance evaluation and personnel management. This system and its concept is primarily aimed to help a supervisor keep better track of the production in real time. Subsequently, this creates a production optimized environment where lethargy and inefficiency can be greatly reduced by careful monitoring.

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