Getting serial data from multiple Qiks on one Arduino

Hi. We have daisy-chained two Qiks so that one Arduino Mega controls motor speeds on both. (We chose to use one of the Mega’s four serial ports rather than using softserial.) All works well. However, it would be ideal if we could also get some information from each Qik (e.g., get motor current). We note that the Qik user manual states that “connecting multiple serial outputs to one serial input is more complicated” and that “you can use an AND gate (since the idle state is high)”. We would love it if you could give us more details as to what we need to do so that we can use one Arduino to request info from one of the two Qiks. Thanks.

Hello, jonathang.

To receive serial data back from multiple daisy-chained Qiks, you will need to pass the serial lines that return to your Arduino through an AND gate so they do not conflict with each other. Since the idle state is high, when one of the Qiks is sending information back, that signal will be sent to the Arduino without directly shorting out with high signal from another Qik. The output of the AND gate can be connected to your Arduino’s RX pin. You might be able to find an AND gate package at your local electronics supply store or online at sites like DigiKey Electronics.


Thanks Brandon. That makes sense. I’ll make an AND gate with two NPN transistors and give it a whirl.