# RC and direction changing

Hi everyone,

I'am aiming to start a RC car project, I know it's been done many times, but still I want to do mine.
I have a few questions about the radio communication, I have watched this video (nRF24L01 30km challenge! - YouTube) which connect two arduino boards from a distance up to 30KM, but the problem is that the antennas needs to keep pointing at each other, I probably won't be facing this problem since I will be controlling my car from a distance of at max 100 meters, but let's assume that I want to make it controllable from a distance around 10 km, how do I avoid the pointing antennas problem since my car will be moving and rotating so It's nearly impossible to keep pointing at it ? Thanks in advance

but let’s assume that I want to make it controllable from a distance around 10 km

Why? You can’t see your car at that distance so how are you going to know how to control it?
A distance of 100 meters is quite feasible with unidirectional wip antennae.

I don’t think you understand what that video is showing you. It is not in any way suggesting it can be used as a mobile car controller. Also by putting those antennas on those modules you make them illegal because you are exceeding the permitted peak emission power.

Grumpy_Mike:
Why? You can’t see your car at that distance so how are you going to know how to control it?
A distance of 100 meters is quite feasible with unidirectional wip antennae.

I don’t think you understand what that video is showing you. It is not in any way suggesting it can be used as a mobile car controller. Also by putting those antennas on those modules you make them illegal because you are exceeding the permitted peak emission power.

I was thinking of a camera placed on the car, and the data gets transferred to the Arduino on my hands so I'll be able to control the car wherever it goes, I understand that the video is for immobile examples, that's why i'm asking about mobiles one (if possible of course)

If you are expecting the arduino to handle image data, I think you will be disappointed.

vinceherman:
If you are expecting the arduino to handle image data, I think you will be disappointed.

Actually, this video is more close to what I need to be done (RC car GPS telemetry (arduino + nRF24L01 + android) - YouTube), It's handling images very well, do you think it's using something beside Arduino ? and about the Omnidirectional antennas, are they long range ? Thanks for your time by the way

sufianetouil:
and about the Omnidirectional antennas, are they long range ? Thanks for your time by the way

No.

Yagis are used because they provide a fair bit of gain. You dont get something for nothing, so yagis are highly directional.

As has already been suggested, using high gain antennas for such applications is often illegal.

The comment on the video says:-

Using Android to display ack payload info from RC car.

Android is an operating system which runs on something many orders of magnitudes of power greater than the Arduino has.

and about the Omnidirectional antennas, are they long range ?

That makes little sense. The range of a transmitter is related to the power budget of the link, the antenna gain is only one factor in this. But no, their is no gain in an omnidirectional directional antenna so it dosn't help. But any other type of antenna is not feasible for your project because as you say you can not have anything directional as you can't predict what orientation the car has.

srnet:
No.

Yagis are used because they provide a fair bit of gain. You dont get something for nothing, so yagis are highly directional.

As has already been suggested, using high gain antennas for such applications is often illegal.

Grumpy_Mike:
The comment on the video says:-Android is an operating system which runs on something many orders of magnitudes of power greater than the Arduino has.
That makes little sense. The range of a transmitter is related to the power budget of the link, the antenna gain is only one factor in this. But no, their is no gain in an omnidirectional directional antenna so it dosn't help. But any other type of antenna is not feasible for your project because as you say you can not have anything directional as you can't predict what orientation the car has.

Ok, thanks everyone for your answers, I will stick to the short distance then.