You know when it comes to New Years and Independence Day, you always get to see some really exotic, beautiful fireworks. Well, all those fireworks are nowdays controlled by an ignition control system but here’s how to make one for yourself.
At the heart of my firework ignition system is an SX48 running at 50 MHz. I was able to make full use of the SX’s 36 IO pins. Thirty lines are dedicated to the 30 channels. Two lines connect to a MAX233 chip for serial port control. Another line is connected to a 7805 (TO-92) which monitors the state of the arming key. The remaining 3 lines are used to communicate with the PIC A/D converter via an SPI interface. The system was built with cost as an important factor. At $10 the SX48 Proto board was an easy choice with its incorporated 5V regulator, led and all the difficult surface mount soldering already done for me. I also designed 2 pc boards using the freeware version of Cadsoft’s Eagle. The interface board connects the SX48 Proto board and contains the MAX233 chip, A/D converter and 30 LEDs to represent the state of each of the 30 channels.