NXT Connectivity Question

[yoraish]

As you know Bluetooth is way better than IR when talking about remote control.

My target is to control a PF powered truck with bluetooth.

My idea was to use the PF extension wire and the NXT converter cable to control PF motors directly from the NXT unit.

Now my question is, will such an arrangement work properly and deliver the maximum power as possible?

Or is there no other way but an HiTechnic IR sensor?

Thanks for your help.

[DLuders]

Have you seen Philo's "Power Functions NXT Remote Control" webpage? Maybe the logic can be reversed:

Edited October 18, 2011 by DLuders

[Jim]

Also bear in mind that BT communication has a slight delay, so it will probably not be as responsive as IR.

What do you want to achieve? Controlling your model with a mobile phone?

Edited October 19, 2011 by Gekke Ted

[Philo]

The voltage in the NXT and the motor driver chips are the same as the one used in PF IR receiver, so yes, the NXT should deliver the same power as the PF system.

@dluders: no, it's not really possible to "reverse" the logic...

[Burf2000]

I have done this, and BT is crap, it was too delayed for me, unstable and poor to connect up. It's quite well known that the BT on the NXT is rubbish.

[yoraish]

Thanks for your responses!

I have done this, and BT is crap, it was too delayed for me, unstable and poor to connect up. It's quite well known that the BT on the NXT is rubbish.

I have never heard that before. I am trying to use BT because I usually run my models outdoors, and the sunlight messes with the IR connections. The only way is to place the remote very close to the receivers. A really uncomfortable solution. And so far the delay you talked about didn't really bother me. So can you explain a bit more about that delay?

[Jim]

Thanks for your responses!

I have never heard that before. I am trying to use BT because I usually run my models outdoors, and the sunlight messes with the IR connections. The only way is to place the remote very close to the receivers. A really uncomfortable solution. And so far the delay you talked about didn't really bother me. So can you explain a bit more about that delay?

For driving vehicles it's probably negligible, but operating an NXT robot with high precision can be a pain in the ...

So it totally depends on the setup.

[Burf2000]

So right I clarify my response a bit better so I don't get flamed :)

While investigating PC to NXT communication I ran in to reports of it being quite unstable and some BT dongles did not work, etc I just read to many bad things (this was around 2 years a go)

So I went with using RobotC(Brilliant) and 2 NXT's (master slave) I wanted to have (master, slave, slave slave) but was told that the way bluetooth worked, the switching between slaves could be slow.

Anyway I build a large robot (my avatar) that used 2 master slave (1 per hand) which allowed my direct movement of arms to affect the moment of the robots arms.

Also trying to get 2 NXT's to connect involved resetting the BT quite often and pairing them both back up. Also had to take the battery out quite often.

However there was a extra switch on 1 that would allow me also to use it to drive the robot about (accelerometer).

I first noticed how bad BT was via switching modes. All this was was a NXT button on the master and it would show the mode on the slave NXT. Half the time this just did not work and it was not my code (prof coder for over 10 years)

Then between the lag of the BT with the lag of the Hitechnic IR link meant that if you needed to stop suddenly, you had to expect it to go forward for a few seconds.

This resulted in my large robot driving itself in to a table after 30 mins of the show it was at opening :(

This year I used a Mindsensor PS2 controller setup and it was fantastic! I plan to buy a few more!

[yoraish]

This resulted in my large robot driving itself in to a table after 30 mins of the show it was at opening :(

I'm sorry for your robot .

I have some experience with NXTs and I know what you're talking about. I guess that for my use (controlling trucks) the NXT-NXT/Phone-NXT BT connection should work fine.

Thanks for your great answer.

[cybermaster7]

Here is my soultion. Don't bother with IR, bluetooth, use full 6 channel FM rc control. http://www.youtube.c...h?v=IWeRBPRbOzw (this is my first video post)

It is control by Vex robotic rc system (www.vexrobotics.com), 6 channel radio, 4 analog (variable speed, forward and reverse) and 2 digital channels (single speed only, forward and reverse). You will also need the singal splitter and 6 motor controller 29 (converted PWM singal to drive the lego motors). I have to sacrifice 3 lego techinic connector wires and attatched the bec connectors (the little red connector, www.maxxprod.com), so it would be easier to switch to a differnt motors. The signal splitter take 7.2 or 9.6 volt battery. Range of the rc system is few hundred feet. I came up with the sytem few years ago, but just never have the time to buy all the parts to make it work till now.

You might able to make it work by connecting the motor controller 29 to regular rc esc, there fore using regualr rc controller rather than the vex rc system. I did not have tiem to try that yet.