How to interface Arudino with external serial device?

Using Arduino Networking, Protocols, and Devices
1

I have ATmega based Geiger detector that has serial interface. How would I setup Arduino Uno to receive data from it? Any hints are much appreciated :slight_smile:
Ideally I want to use SD DataLogger shield to log CPMs from geiger detector (without computer).

2

If the Geiger detector has a TTL (5V) Serial interface you would just connect the detector Ground to Arduino Ground and the one or two serial pins to one or two Arduino digital pins. Then use SoftwareSerial to talk to the device.

If the Geiger detector has an RS232 Serial interface you need an RS232-to-TTL level converter between it and the Arduino.

3

johnwasser:
If the Geiger detector has a TTL (5V) Serial interface you would just connect the detector Ground to Arduino Ground and the one or two serial pins to one or two Arduino digital pins. Then use SoftwareSerial to talk to the device.

If the Geiger detector has an RS232 Serial interface you need an RS232-to-TTL level converter between it and the Arduino.

It's ATtiny2313 based (MightyOhm geiger kit), form what I can tell it's straight ATtiny2313 to serial header (no other ICs other than 555), but it's 3 Volt based, so that could be a problem?