You are reading a single comment by @Gordon and its replies.
Click here to read the full conversation.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
@Gordon
It shouldn't matter that the voltage regulators are unconnected, as long as GND is connected together.
Did you add series resistors to the LEDs? As in my post above, that might explain why the receive LED isn't lighting and why you're not actually receiving data with the LEDs attached.
Have you used a meter with a continuity check between B6 on the master and B7 on the slaves?
Right now it seems that pullup resistors are not the problem - if the LED isn't lighting at the master, it's to do with pulling down to 0 rather than pulling up.
With a lot of slaves you might need a bigger pullup resistor, but at some point and with longer lengths of wire, you'll probably need to start using special line drivers like RS485 - over longer distances and with more nodes, you'll get more noise coming in, which won't be good to feed straight into the Picos.