need solution on voltage level translation

[vishu489]

hi friends I'm trying to interface glucometers with atmega16 on uart. but the problem is that one of my glucometer gives LVTTL interface logic(0 to 3.3v) and another one gives rs232 signal (-12V t0 +12v)
and one more glucometer gives TTL o/p (0 to 5v). but the problem is that my controller is capable to read signal ranging from 0 to 3.3v. so how can i make my atmega16 uart compatible with all 3 meters.
basically i need voltage conversion solution so that what will be the voltage coming from glucometer , it should be converted into voltage compatible with atmega16 uart. thank you in advance:lol::lol:

 

[jayanth.devarayanadurga]

You can use MAX232 to convert RS232 voltage to TTL level. You can use this https://www.sparkfun.com/products/8745 for connecting signal pins of glucometer to ATMega16. And you can directly connect the glucometer giving 0-5v TTL signals to ATMega16.

 

[vishu489]

thanks for your reply. but that solution i already know . i don't want to change hardware every time i change my glucometer. i want one global solution such that i can maintain compatibility with different glucometer.

i wanted to do something as below

glucometer(o/p: LVTTL, TTL ,RS232) -------> VOLTAGE TRANSLATION---------> ATMEGA16 UART

that voltage translation must have to sense this logic and convert it into compatible signal of atmega16 uart(LVTTL)