Opinion wanted on using Xbee modules for radio control of a R/C boat

w4fej

Can the Xbee Pro modules be effectivley used to control an R/C boat? I want to be able to send commands to the boat and read sensors on the boat and send them back to the controller. Using Prop boards on each end.. The Pro 60mw version claims up to 1 mile range and this boat would be WAY under 1 mile, more like a few hundred yards..

I assume with the right Spin code they (the Xbee's) can communicate back and forth. Would the data exchange rate be fast enough to send (for example) steering commands to the boat in a SMOOTH manner just like you might expect a conventional R/C transmitter to have?? I want to read from the boat things like propeller RPM, battery voltage, water in the boat?? etc..

Size and weight are not an issue at all. The "house" battery will be a deep discharge, 12VDC marine battery so regulation down to 3.3vdc or what ever is easily accomodated in the boat..

I have The prop boards, an HB25 controller, Parallax servo controller and various other Parallax goodies and will buy a pair of the Xbee's if it looks like it is a good fit for this project...

All opinions are welcome..
Thank you, Mike B.

Mike Green

A pair of xBee Pro modules should work fine for the sort of range you're talking about. For best range, mount the xBee as high as possible above the water line and run +3.3V/Gnd/Tx/Rx to it. You can also get an xBee module for use with an external antenna and mount the antenna above deck (like this one) with some kind of waterproofing. The data rate won't be as high as you think since you only have to send position/speed changes to the boat, not the constant R/C pulses you're used to and changes don't happen that quickly with manual controls. The controller on the boat can smooth out any changes sent to it if need be.

Consider using a switching regulator for the electronics, something like this.

Duane Degn

Paul K. has built some nice controllers using the XBee.

I'm used both XBees and Nordic nRF24L01+ transceivers as remotes for some ground based robots. Apparently the XBees (and probably the Nordics) are fast enough to control quadcopters successfully.

I personally like to use the Nordic modules for wireless projects since they are so inexpensive. There's a link to an ebay source of inexpensive Nordic modules in post #1 of my index (see my signature). The Nordics aren't as easy to use as the XBees but I think they are faster than XBees.

If you use the regulator Mike linked to, you might need to use some shielding around it. Those regulators can produce a lot of radio interference.

Ragtop

I am putting the finishing touches on a RF remote I made using an xbox controller case and the nordic transceivers.

I removed the joysticks and triggers for my project, but if those could be left in this seems like a perfect RF prop powered remote.

[video=youtube_share;wC72W8m6RuM]

JLocke

Duane Degn wrote: »

I'm used both XBees and Nordic nRF24L01+ transceivers as remotes for some ground based robots.

I know you are a big proponent of the Nordic modules. What kind of range do you typically get out of those? I tried to use a Nordic 'fob' module to transmit to the Nordic module transceiver, and found I could only get about a 15-foot range. (I'm trying to wire a garage door opener; the original trigger modules are lost and it's an old unit). I couldn't get the module to trigger from halfway down the driveway with the garage door open. I've since ordered another Nordic transceiver with the 'duck' antenna to see how that picks up the range, but haven't had time to get back to the project. Anyway, I was wondering if the range was better, transceiver-to-transceiver?

Duane Degn

JLocke wrote: »

I know you are a big proponent of the Nordic modules. What kind of range do you typically get out of those? I tried to use a Nordic 'fob' module to transmit to the Nordic module transceiver, and found I could only get about a 15-foot range. (I'm trying to wire a garage door opener; the original trigger modules are lost and it's an old unit). I couldn't get the module to trigger from halfway down the driveway with the garage door open. I've since ordered another Nordic transceiver with the 'duck' antenna to see how that picks up the range, but haven't had time to get back to the project. Anyway, I was wondering if the range was better, transceiver-to-transceiver?

I could only find a few places in my house where the Nordic fob wouldn't transmit across our home (maybe 80ft?). The couple of places that didn't work were places the transmission had to pass through heavy appliances like the refrigerator or oven. I tested both the SparkFun modules and the modules from Hong Kong with the Nordic fob and I thought they both worked fine.

I haven't tested the various antenna myself but I'd suspect the "duck" antenna may work better than a PCB antenna. I wouldn't bother getting the "large" antenna. I've found large 2.4GHz antennas just add more plastic; the actual antenna inside is the same size (very small).

How were you powering the receiver? As I mentioned above, I've had severe interference problems using switching regulators.

JLocke

I don't want to hijack this topic, so briefly... using a linear regulator with the circuit on a breadboard. I think the regulator is good for 500mA; the wall-wort powering everything is good to 1.2A. I had the breadboard circuit about 8 feet inside the garage with an LED indicator to indicate receipt of the fob 'trigger'. I walked out the garage and kept pressing the button on the fob; I quit receiving probably 7-10 feet down the driveway. I'll let you know after I have time to get back to it (maybe in a couple of weeks?).

w4fej

Hmmm.. I don't know what happened but I replied to this thread the day it was posted. I wanted to thank Mike Green for his answer but for some reason the reply didn't make it to the thread??

Anyway Mike G., the antenna will be about three foot above the water and I can't imagine the boat getting much more than a couple hundred yards away from the controller.. Looking forward to getting and learning about the Xbee Pro...

Gotcha on the regulator. Being a ham radio op I can testify to the RFI generated by switchers especially on HF frequencies. An RFI tight enclosure may be in order.. Like the Marines say, "what ever it takes!".
Again, thanks to everyone that replied, I now feel confident in using the Xbees for this project..

Let's see if this makes it to the forum this time..