The project was aimed at making a special timer with circular shape with 3cm diameter and that was to be enclosed in a cylindrical tube. The timer had to be capable of triggering a specific number of buzzers according to programmed schedule conditions. Also, along with the buzzers, some LEDs with specific colors were to be turned on /off. Other requirements included including a function key for scheduling the design plus an on/off and a reset bottom.
The main challenge with this work was the small size of the board that made the choice of proper components difficult. The other challenge was clients request for making a fully functional prototype in a one-time prototyping without getting into a 2nd iteration.
In order to resolve the above challenges, a PIC16C61 was used. This microcontroller has enhanced core features, like an eight-level deep stack, and multiple internal and external interrupt sources. It also has 36 bytes of RAM and 13 I/O in addition to a timer/counter. These features plus its small size of 7.62mm x 22.479mm made it a good choice for the design. As a result, most of the design was embedded in the firmware without the need for any additional components. Also, all of the components were chosen to be an SMT type.
In the design, a bi-color LED and a buzzer was used to indicate different output states. Also, 5 pin jumpers were installed on the board allowing optional change of the firmware.
In order to make sure that the one-time prototyping requirement is met, the final design was simulated with different simulation software. After this step was successfully passed, the design was submitted for the prototyping.
Final Result and feedback:
The whole project took about 4 weeks and the first prototype was fully functional and compatible with all the requirements set by the client. The manufactured timer was installed in the device enclosure and was successfully tested by the client. Having finished the project within the given deadline and also the device’s good performance received the full satisfaction of the client.