Hello all, this is my first post to this forum so apologies in advance for any poor etiquette.

I am getting back into Lego after decades of absence and I am learning NXT from scratch and essentially a newbie. I am doing a MOC build that requires coordinated action and bi-directional communication between two NXT bricks, via Bluetooth I suppose. However, I am having quite a bit of trouble when I am testing out these capabilities. I have a few basic questions I wanted to see if anyone can help:

1. Let's say I manually connect the primary NXT to the secondary. When I run a program right after that I could send messages (Numbers, not text) from the primary to the secondary. However, I can't get the secondary to successfully send a message back to the primary. Are BT messages inherently uni-directional (i.e. from primary to secondary, when primary is the device that initiated the BT connection).
2. Do I have to disconnect and reconnect BT after I download a new program to the NXT? I find that the uni-directional messages don't even work after a new program download to either the primary or secondary.
3. Do text messages work over BT? I'm using the Mindstorms NXT GUI to program the brick, and I'm having trouble sending text messages across BT - can't quite figure out how to make it work!
4. Are there better programming tools other than the Mindsotrms NXT GUI? I find the drag-and-drop logic extremely convenient, but it's really slow when dealing with complex logic or calculations. I tried Java with LeJOS but I don't quite seem to find any support for NXT-to-NXT communications via BT. I also can't seem to figure out how to do precision motor controls with LeJOS. Their forum is closed to new users and their admins don't seem to be replying to requests to join their forum.
5. Would I have better luck with EV3? Seems like there is both BT and WiFi support. Does brick-to-brick communication work better when EV3 devices are connected to each other via WiFi?

For additional context, both NXTs are running 1.31 Firmware, AVR/BC4 version 1.01 and Build 1903121214. Any help will be appreciated!

Thanks,
- TA

I would not recommend EV3 with LeJOS, (which I used and worked fine), it is pretty rare and expensive.

If you are looking quick and simple use the powered up hubs and a M5Stack ATOM for running  the one and only program.

It's much easier.

On 10/23/2023 at 12:51 AM, Lok24 said:

I would not recommend EV3 with LeJOS, (which I used and worked fine), it is pretty rare and expensive.

If you are looking quick and simple use the powered up hubs and a M5Stack ATOM for running  the one and only program.

It's much easier.

Appreciate the note Lok24!

With some unexpected inspiration I managed to use a color wheel with a color sensor to replace several touch sensors so I can build with exactly 4 sensors now. This means I can use a single brick and not worry about cross-brick communications.

This will allow me to focus on the build and core functional coding. I’m going to give it a try with a stock EV3 and the standard Mindstorms EV3 drag-and-drop programming software. It should do the job.

I also looked into PyBricks, pretty cool and will switch to that if the current plan does not pan out. I’ll keep the folks here posted if anyone is interested!

Cheers,

- TA

10 hours ago, TechnicAddict said:

so I can build with exactly 4 sensors now

If you use a motor as a sensor (for your wheel e.g) you can increase number of sensors.

Yeah Lok24, I noticed that. I think someone made an analog joystick out of that, pretty nifty feature!