I have an arduino device that is currently attached via usb cable to my computer. I can see data readings from the arduino device's sensors in hyperterminal, but I would like to have that same data transmitted over 3 wire RS-232 to another device. Does anyone know how to accomplish this without modifying any code?
Maybe a cable exists already to both power the arduino via USB and have the data come out in a 3 wire fashion?
I'd also be willing co splice multiple cables together if someone could guide me on how to do so.
The data exists on the Rx and Tx pins at TTL levels , you can use that via a Max232 chip to get RS232 signals .
You can also get RS232 to USB leads .
Power the Arduino , by some other route .
What kind of Arduino is Your "device"?
Software serial is way to create a second channel using RS232 level converters if Your "device" doesn't have it already.
Railroader:
What kind of Arduino is Your "device"?
Software serial is way to create a second channel using RS232 level converters if Your "device" doesn't have it already.
hammy:
The data exists on the Rx and Tx pins at TTL levels , you can use that via a Max232 chip to get RS232 signals .
You can also get RS232 to USB leads .
Power the Arduino , by some other route .
So the data I'm seeing over the USB cable is also automatically transmitted via the Tx pin on the board? What does the max232 chip do? Why can't I just wire the Tx on the arduino to the Rx on the other device?
The RX and TX pins connect to the on board USB interface chip and are the same signals .
You can connect these signals to another device that will accept them at that voltage level . The MAX 232 converts the signal to standard RS232 levels .
granola123:
So the data I'm seeing over the USB cable is also automatically transmitted via the Tx pin on the board? What does the max232 chip do? Why can't I just wire the Tx on the arduino to the Rx on the other device?
'
Because the Tx and RX pins from the Arduino are 5V to 0V levels, which is also called (TTL level). RS232 standard requires +/- 12 volts for the logic levels, so that's what an an RS232 device expects. Years ago, MAXIM came up with a nice one chip solution, requiring only a couple of small capacitors to make the conversion, so it is an easy addition.
hammy:
The RX and TX pins connect to the on board USB interface chip and are the same signals .
You can connect these signals to another device that will accept them at that voltage level . The MAX 232 converts the signal to standard RS232 levels .
Get Googling !
PeterPan321:
'
Because the Tx and RX pins from the Arduino are 5V to 0V levels, which is also called (TTL level). RS232 standard requires +/- 12 volts for the logic levels, so that's what an an RS232 device expects. Years ago, MAXIM came up with a nice one chip solution, requiring only a couple of small capacitors to make the conversion, so it is an easy addition.
Thanks for your help. I will attack things from this angle. I've honestly put a decent effort into trying to figure this out myself, but sometimes it's hard to know what to google when you are't too familiar with a topic.
