Mydaq digital sensor connection

[jkptz7]

Hi Folks,

   I'm working on a project that requires me to take a whole gamut of senor readings (4-5 air pressure readings, 2 high temperature readings (~950-1000 F) and 1 "low" temperature reading -> thermocouples with appropriate signal conditioning, 1 or 2 tachometer readings (1 at ~<100,000 rpm), 2 or 3 voltage readings, and I also need to generate at least 1 PWM signal). I have two myDaqs and was planning on:

1. using analog multiplexing for as many AI signals as possible without taking up too many DO pins and while keeping at least 1-2Hz sampling per sensor multiplexed

2. using a reflective ir emitter/detector with one the myDaq's counters for the tachometer

What I'm unsure of is what digital sensor interface is compatible with myDaq DI pins. I'm not a Comp. E. and as I look at the digital sensor selection on digikey or mouser, I see different protocols for the digital sensor outputs. I know from reading this forum that I2C is not supported, but what should I look for in a sensor (SPI? UART? Asking the wrong question?)? What about ADC's? Is it possible/advisable to use an ADC to generate a digital signal from an analog source if a digital sensor of a certain type is unavailable? If so what should I look for? Also, given my daq devices, is this plan even possible? I'm a college student and short on cash, so can someone suggest an alternative daq device if two mydaqs won't cut it? Sorry for the laundry list of questions!

   Thank you very much!

      James

[Hockeyjim07]

Hi Jkptz7,

This certainly is a load of questions and hopefully someone else will jump in here to help out. As far as the digital connections go on the myDAQ:

" The eight digital input and digital output lines (3.3 V TTL-compatible) help students interface both low voltage TTL (LVTTL) and 5 V TTL digital circuits. "

You will get a signal for anything that is in that range of voltage, can you give a few examples of digital devices you will be monitoring from? I think you may simply be asking too much from the myDAQ but I would like if you could clarify the actual tasks you expect it to preform.