Long distance (400 meters) RF remote control for The Sea.

Hello all!

I am developing a robot who can be driven on The Sea. And I need some modules to connect to the Arduino (one for the robot, and other for the remote control).

I need a range of 400m aprox.

Another thing, is that I need to drive 2 servos. And I developed it for control it through 2G network. But I am having a lot of RFI, and the servos move alone. This topic is treated in other thread.

Can it be possible? Does it exist?

Thanks in advance.

Abel.

Do you have the luxury of a masthead antenna? Waves at sea can get in the way.

so expensive, is this what did you mean?

What's about using a GPS on the sea? P4B6 for example...

I'd be inclined to pick up a couple of old CB radios at a car boot sale. They're cheap as chips and would be good for about 20 miles with a high enough antena.

That's a great idea, but ... is very heavy for the robot.

I am thinking in just using a GPS. At the sea, RC seems to don't be a good idea for long distances and also it is better idea because the true is that I just want the robot to go to a point and come back, so I am studying of how to drive it by a GPS...

Just to know, does a GPS module has something like Compass? I need to know how much turn right/left for getting into the path... Is this possible (navigation) without compass, just with GPS?

Look at these websites Deltang and Deltino.

The devices use an Atmega 328 and can be programmed as an Arduino. The principal market for the Deltang units is for Radio Control so they probably have considerable range. Email DavidT for more info.

I have used the Deltino devices for radio control of model trains but, of course, I don't need 400m range. I use one device as a master (connected to my PC) and others as slaves in the locomotives.

...R

Hello Robin2,

thanks for the info and links.

I just emailed DavidT.

Waiting for his answer ;).

Cheers,

Abel.

GPS can be a heading (not bearing) compass while you are in motion. Once you stop moving, you don't know what direction you are pointing.

Magnetometers are inexpensive and work for bearing (not heading) whether moving or stopped.

I need bearing for pointing the robot in right direction and heading to know did I arrive.

Thanks a lot, I am buying a magnetic compass.

Google "HM-TRP", a module made by HopeRF. You'll find it in formats that work via USB or plain, arduino-friendly TTL serial -- think of it as a simple, wireless, serial link. Range is around 1 mile but the output power can be adjusted lower. Frequency is available in 433, 470, 868, or 915 MHz; selection is based on what side of the planet you're on.

Wow dude, that's amazing. It seems it would be very helpful for my robot! :O

I'll decide tomorrow if giving a chance, because I discovered my GSM module is noising with EMI the mega 2560 chip. And a mate told me it's a big problem. So I asked if someone has a solution for this.

Thanks! I was looking for something like this for long time ;).

Cheers,

Abel.

Hello!

I've solved my problem of EMI with my GSM module and rest of hardware. Just used Faraday's cage (mini home made version).

So now, I'm going to buy a great Quad-band antenna for the module, and also a GPS with SMA connector for antenna.

Would be possible to communicate over the air by the GSM technology, and at the same time, receive GPS waves on the GPS antenna, without any EMI, or any problematic EMI?

Thanks a lot,

hoping for your answers.

Cheers,

Abel.

abeltomillo: Would be possible to communicate over the air by the GSM technology, and at the same time, receive GPS waves on the GPS antenna, without any EMI, or any problematic EMI?

Yes, smartphones do it all day long. Just separate the GPS and GSM antennas as much as you can (for example, one in the bow and one in the stern) and shield between them.

Thanks a lot mate! You're right, smartphones do it all the time!

Fine!

Cheers,

Abel.

Just another question.

I had very painful EMI by the GSM shield, in the whole devices. I did a simple mini Faraday's cage, and putted al the hardware inside, but not the module of GSM. Then worked fine, but, my actual GPS has not SMA connector for external antenna, so I must put it out the cage.

As there'r about 6 wires connected to the Arduino Mega 2560... will I have EMI on the 2560 again??

That will be very sad. Do you think I should buy a GPS with external antenna?

Thanks mates, very helpful all of you.

Cheers,

Abel.

abeltomillo: Do you think I should buy a GPS with external antenna?

Not yet.

I'm assuming this GPS module is TTL RS232 serial? You can run the serial wires a long distance away from your GSM module to separate the antennas. Further, you can put a coil or choke on one end if the wires. Finally, you can twist a ground wire together with the TX wire and wrap the wire bundle in metallic shielding.

Not sure how much of that will actually be necessary... you can just keep adding one countermeasure after another until the EMI is eliminated.

Okay, I'll start using my actual GPS, and try to fight the possible EMIs.

I think I've got some exp. on this subject, after 7 days of non-stop against an evil GSM module ;).

Cheers,

Thanks.

Abel.