I have 112 switches that output a 0 or 5 volts. I need a way to send this to an Arduino, MEGA2560 , by the serial port, using some CMOS logic or? so that I can tell which switches have changed state. Normal condition is that all 112 are HI=5 volts. Ideas please. The Arduino and the switches are about 5 feet apart but in a noisy environment. thanks
THey are as you described external and I don't have any way to connect to the Arduino except as a serial line. I am hoping someone will have some idea of what CMOS logic chips might do the job. I realize that this is not a simple problem but I am willing to build the PCB to put the chips on it. Just haven't worked with CMOS for some time and need some help with the CMOS family, decoders, etc... also need to take the logic output and have a way to read the data. I did think that a way would be to use 2 MEGAs, since that would give me enough inpins and then send the data from these to the remote ARduino via the serial line. Although not cheap it it seems that it might be the simplest... Opins?
I suddenly realized that I can arrange the 112 as a 7 x16 array...
thanks for the advice. I suddenly realized that I can arrange the 112 as a 7 x16 array , read it with an Arduino and send the data to the main Mega... I am sure that the code to read an array is in a library... anyone know where I could look for this? The switches are all fully floating so making them as an array is simple.thanks
The switches are all fully floating