Section Control - USB Machine Control V5.5 - Bluetooth Issue

I am attempting to use a Bluetooth module to connect my machine control nano to my tablet. I’m simply hooking the bluetooth module to the nano Tx/Rx pins. When I hook up more than 2 sections it continually cycles the relays when they are supposed to be activated. If I connected to my tablet via USB cable it works fine. Anyone have an idea why adding in the BT module would do this?


What sort of power supply are you using for the nano? To me it sounds as if you aren’t getting enough current to the relays when you don’t have the 5v from the usb.

I’m using a 12v adapter. Same adapter I’m using when hardwired. I’m triggering relays when voltage goes high. Maybe the BT module is consuming too much power? I’ll try connecting it to a different power source as it’s getting 5v from the nano now.

I doubt the BT module is using very much power. Check the rated current for the 12v adapter. When you have the nano connected via usb the system will receive a fair bit of current from the usb connection(aprox 500ma max). Keep in mind that each relay needs about ~70 ma when activated.

12v - 2amp so that should be plenty. I’ll do some more testing tomorrow with the power source(s).

I think it has to do with hooking my BT module to the hardware serial ports. Might need to use software serial ports and not disturb the hardware ports but I’m not versed enough in arduino coding to make these changes myself. Probably need to fall back to hardwiring unfortunately….