Long Range Transmitter

Hello

I am proposing to build a handheld controller incorporating an Arduino/433Mhz unit that communicates directly with an Ardunio/433Mhz ground receiver approximately 1.5km away. The receiver will then input signal through an ESC to ultimately control a brushless motor.

The alternative is the handheld unit incorporate incorporates a micro Arduino/Bluetooth that connects to another base unit incorporating Arduino/Bluetooth/433Mhz. The controller inputs would then be transmitted via a 433Mhz long range module.

Essential Requirements:
It will be able to communicate 6 channel signals with PWM output on the 433Mhz receiver as this is a requirement of the ESC. The handheld unit needs to be as compact as possible while incorporating a battery.

Preferable:
The battery is sufficient for approximately 6 hours continuous use.

Is this possible? Does anyone know of any examples where this has been implemented in the past? Any alternative methods? I am essentially recreating a long range compact rc controller with trigger and buttons/switches.

Thank you

Plan on line of sight communications only at that frequency.

It will be able to communicate 6 channel signals with PWM output on the 433Mhz receiver as this is a requirement of the ESC.

You would send a few bytes that specify the PWM signals to be generated by the receiving electronics.

HC-12, RFM69 and LoRa all have this ability - especially when you have line of sight. With obstacles you're probably down to LoRa.

Why six channels? All you have to do is send the update PWM value for the motors when there's a change, and let the receiving controller deal with it. The last thing you should do is try and send the PWM signal itself over the air!

you don't say where you are. therefore, we don't know which rules apply. the following info is for people under the benevolent jurisdiction of the FCC.

RF modules for Arduinos are mostly Part 15 devices. Part 15 is an unlicensed low power radio service. Part 15 devices are limited to a low EIRP ( Effective Isotropic Radiated Power ) output. EIRP is a combination of transmit power and antenna gain

bottom line: Part 15 output power + antenna gain is limited. By contrast, in amateur radio, transmitter output is limited to a very generous level, and you can effectively increase that with a high gain antenna. you can't legally do this with Part 15 devices.

you may have noticed that in your lifetime, the number of people busted for exceeding Part 15 power limits is exactly equal to the number of people who got stomach cramps and drowned from swimming 59 minutes after eating. I only mention this because for some people in some work environments strict adherence to the letter of the law is necessary.

Part 15 is a legal unlicensed use of a licensed band. 433 mhz and 915 mhz are shared bands. The government gets first priority, licensed amateur radio operators get second priority, and Part 15 gets what is left. you may find yourself clobbered by RADAR or the ham up the street bouncing signals off the moon with 1500 watts and a vast gain array. as a user of an unlicensed band, interference from a licensed operator means tough luck, Chuck. the good thing is there are thousands of designs for DIY antennas designed by hams on the internet.

for continuous transfer of data I would use HC-12 modules. This is my current project, I have no results to report yet. The HC-12 sends serial data. therefore, I must have serial data to send. the sensors do not generate serial data, so the plan is ( far end ) SPI & I2C sensors >NANO > serial port > HC-12 > ( the sky ) HC-12 > serial port > NANO > one pin to trigger the MEGA and an I2C connection for the sensor data. I plan on having far too many sensors for direct serial connections to the MEGA. You may need something like this, send values through the serial port that get converted to PWM at the downstream end.

When the distance gets large, which definitely includes 1.5 km. you have to lower the bit rate to get the distance. you have to use specialized modulation schemes, and you have a limit on packet size.

research HC-12 radios, and LoRa. LoRa claims the range you are looking for, but in bursts of data at sporadic intervals

you are not going to get the range you want, high data rate, and compact antennas. the laws of man and the laws of physics won't support that.

a thing to know about antennas: a higher gain antenna on one end bestows it's blessings on both ends of the link. if you replace a standard issue rubber duck antenna with 2.14 dbi gain ( you are on your own if you want to know more about db & dbi ). if you replace your 2.14 dbi dipole with an 18 dbi yagi, both ends of the link see a 16 dbi improvement in signal strength

higher freguency > shorter antennas > higher gain in a smaller package
higher frequency > shorter range > offset by the benefits of better antennas
high gain antennas get their gain by concentrating power out in one direction, and receiving from a smaller aperture in the sky
if you need a high gain antenna on both ends, and have no practical way to aim and support a directional antenna, the highest gain omnidirectional antenna is a collinear. the practical limit for a collinear is 15 dbi gain. if you try for more, losses in the longer antenna counter the gain of the additional elements. those eBay vendors peddling 18 dbi collinears know new laws of physics they are not sharing.

at 433 mhz, 9 dbi is a practical limit for a collinear. more gain = longer = support structure required.

TwoThings:
Hello

I am proposing to build a handheld controller incorporating an Arduino/433Mhz unit that communicates directly with an Ardunio/433Mhz ground receiver approximately 1.5km away. The receiver will then input signal through an ESC to ultimately control a brushless motor.

The alternative is the handheld unit incorporate incorporates a micro Arduino/Bluetooth that connects to another base unit incorporating Arduino/Bluetooth/433Mhz. The controller inputs would then be transmitted via a 433Mhz long range module.

Essential Requirements:
It will be able to communicate 6 channel signals with PWM output on the 433Mhz receiver as this is a requirement of the ESC. The handheld unit needs to be as compact as possible while incorporating a battery.

Preferable:
The battery is sufficient for approximately 6 hours continuous use.

Is this possible? Does anyone know of any examples where this has been implemented in the past? Any alternative methods? I am essentially recreating a long range compact rc controller with trigger and buttons/switches.

Thank you

Some other things to do that may help your project: survey the area for other devices that operate on 433 mHz as they will interfere with your project.

Finding the receiver with the lowest noise factor and smallest band width will do much more to help your project than adding power to the transmitter, which is limited by law.

Paul

TwoThings:
Is this possible? Does anyone know of any examples where this has been implemented in the past?
I am essentially recreating a long range compact rc controller with trigger and buttons/switches.

OpenLRS has been around for quite a few years now.

Its based on RFM22B\Si4432, its an open source RC control system designed for long range control of RC models.

srnet:
Its based on RFM22B\Si4432, its an open source RC control system designed for long range control of RC models.

That's a quite old radio, its successor is the RFM69 module, offering a.o. better range.

wvmarle:
That's a quite old radio, its successor is the RFM69 module, offering a.o. better range.

Is there an Arduino RC control system, compatible with the RFM69 ?

I don't know of any commercial ones but it can't be that hard to build. After all you have just a few commands: up, down, forward - and maybe a speed number. That's 1-2 bytes per command.

If that RFM22 project is written properly it's transmitter agnostic and will work over any radio.

wvmarle:
If that RFM22 project is written properly it's transmitter agnostic and will work over any radio.

At the hardware level the two devices are quite different though.

The Si4432 is capable enough though, and I think I hold the 'RC' record with the device @ 2,200km

Arguably the world record should be a bit longer... those Voyager probes are remote controlled and are pretty far out by now! But then that's maybe not a "world" record, as it's out of this world...

Anyway, using the Radiohead library I've before used the same code on RFM69 and RFM95 (LoRa), and expect to be able to use the same on HC-12, HC-05, NRF24, and others. That's thanks to them splitting the driver (dealing with the hardware - getting the bits from A to B) form the manager (dealing with the actual message, resends, etc).

Thank you. I appreciate all your responses.

In reply to a few things raised. I am based in Australia where 433Mhz can be used at a maximum EIRP of 25 mW. This being said, I still use my DragonLink UHF RC system which is 500mW. My build purpose is for non-commercial personal use.

I have attached a copy of a controller from an electric skateboard which is the style and ideal size I am aiming for but will compromise where essential.

Given my preferred setup [Arduino/433Mhz TX > Arduino/433Mhz RX], and for reasons of keeping this setup as compact as possible, is there a particular Arduino board and modules that people would recommend.

Is it as simple as getting 2xArduino and 2x433Mhz modules (eg. Lora) and then the remainder of parts? I am new to this space so still learning compatibility, size and functionality of parts. Thank you again for your time.

controller.jpg

TwoThings:
I still use my DragonLink UHF RC system which is 500mW. My build purpose is for non-commercial personal use.

Is it as simple as getting 2xArduino and 2x433Mhz modules (eg. Lora) and then the remainder of parts? I am new to this space so still learning compatibility, size and functionality of parts. Thank you again for your time.

It could be, but it sounds like you are quite willing to use illegal levels of power.

srnet:
It could be, but it sounds like you are quite willing to use illegal levels of power.

UHF RC systems are available in most RC model stores in Australia, all at higher than minimum per levels. In this case I feel laws have failed to keep up with technology advancements but that is for another discussion. Not looking for a right/wrong battle here.

TwoThings:
UHF RC systems are available in most RC model stores in Australia, all at higher than minimum per levels. In this case I feel laws have failed to keep up with technology advancements but that is for another discussion. Not looking for a right/wrong battle here.

Auto stores also sell aftermarket wood rim steering wheels for cars which is fine.

BUT let the local Constable find you driving with it fitted to your car on a road anywhere and you'll go for max.

Get the drift..??

These days also there are eyes and people aware of the aviation rules regarding line of sight, and location, armed with video cameras. Get in the bad books with CASA and you'll be looking out from behind steel bars.

TwoThings:
Not looking for a right/wrong battle here.

A lot of people are not happy to provide free advice, on public forums, for people doing illegal stuff.

I was only asking about a solution to getting a signal max 1.5km away with equipment that is available within this low power Arduino field. From what I see, equipment suggested by users is all very low power but still sufficient for the line of sight purpose. I know the antenna is just as important if not more for effective range.

I am not here to get information to create something that will breach laws. Certainly not my intention. My purpose is to control a winding wheel motor on a farm. I live in a remote area of the country.

thanks

LoRa sounds like a good solution for this.

Can handle some obstruction; it's designed for long range, low power, low data rates - for transmitting hourly sensor data, but can work just as well for a start/stop signal for a pump or so.

TwoThings:
I was only asking about a solution to getting a signal max 1.5km away with equipment that is available within this low power Arduino field. From what I see, equipment suggested by users is all very low power but still sufficient for the line of sight purpose. I know the antenna is just as important if not more for effective range.

I am not here to get information to create something that will breach laws. Certainly not my intention. My purpose is to control a winding wheel motor on a farm. I live in a remote area of the country.

thanks

When the original post does not fully explain the project, things like "6 channel, ESC, brushless motors" are normally associated with Quad copters and the like, hence the warnings.

If you look at the site below, he has several long range applications explained, not just the one here listed.

bluejets:
If you look at the site below, he has several long range applications explained, not just the one here listed.
https://www.youtube.com/watch?v=4XRp7pkZgPM

Thank you