Sending two sensor data from Arduino to Touch Designer

hello

Q. Is there any way I can send x2 (or more) real-time pulse sensor data from Arduino to Touch Designer?

It’s my first post, recently I am trying to connect the x2 pulse sensor to the Arduino and send the real-time pulse data to the Touch designer via Serial DAT. It worked well with x1 pulse sensor on Arduino and I could see real-time pulse sensor data appearing on Serial DAT. However, when 2nd pulse sensor was attached there was a random alphabet appearing on the serial DAT monitor but no essential data was transmitted on the Touch Designer.

What I am trying to achieve is to send x2 pulse sensor data from Arduino to Touch Designer but so far I haven’t solved it by myself.

< Below are what I tried so far (& failed) >
(1) Attach x2 pulse sensor with x1 Arduino UNO, send data to TouchDesigner via USB modem and insert serial DAT. *Result: Serial DAT displayed random alphabets and no essential data was seen on the TD.

(2) Attach x1 pulse sensor on each Arduino UNO, connected on PC via a USB modem. Before opening on serial DAT, realized the second type C port on my mac was for battery only (it’s a shame since this is such a basic).

(3) Use firmata instead serial DAT, later learned firmata is for regulating Arduino from Touch Designer.

Material:
Pulse sensor (from Pulse sensor . com)
Arduino UNO, Arduino R3
USB Modem
M1 MacBook Pro

:see_no_evil:I know this is very basic but I only used both Touch Designer and Arduino for two weeks so any advice is appreciated.

:raised_hands:Thank you for your time & support!