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ExpressLRS for RC models


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After I went bonkers on the covid thing I started on a new obsession. Here's my new thing I been working on.

https://www.expresslrs.org/

"High Performance Open Source Radio Control Link
ExpressLRS aims to provide the best completely open, high refresh radio control link while maintaining a maximum achievable range at that rate with low latency. Vast support of hardware in both 900 MHz and 2.4 GHz frequencies."

It's pretty cool and I like it because of the open source philosophy. Fuck Microsoft!

I figure I should get to know some drone and fixed wing tech for the upcoming war.

I'll post some progress here in the future.

 

 

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0 votes RE: ExpressLRS for RC models

My dad taught himself electrical engineering. And he did, he was a PhD physicist patent lawyer. He had all kinds of BOOKS. I wish we had saved them when we sold the house. Anyway I always wondered what it would be like to be an engineer and have this level of understanding of the world. Must be pretty sweet.

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0 votes RE: ExpressLRS for RC models
M4d said: 

My dad taught himself electrical engineering. And he did, he was a PhD physicist patent lawyer. He had all kinds of BOOKS. I wish we had saved them when we sold the house. Anyway I always wondered what it would be like to be an engineer and have this level of understanding of the world. Must be pretty sweet.

 That's cool your dad sounds like a smart guy. You should make a thread about your dad. I'd love to read it.

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0 votes RE: ExpressLRS for RC models

Being new to thing remote control (RC) flying thing I first had to understand how all the pieces fit together.

Here is a picture of the simplest RC system.

The hand held radio transmitter talks to the radio receiver in the RC airplane. ExpressLRS is the software used to manage and talk. The airplane receiver gets commands and instructions from the hand held transmitter on the ground.

The airplane radio receiver then passes these commands, such as throttle up, throttle down, aileron position, elevator position and rudder position on to the control servo motors and the motor electronic speed control (ESC).

Each servo motor or ESC is on one channel of the receiver.

The airplane receiver is just a slave or middle man to the hand held transmitter on the ground.

More complex systems have a flight control computer with telemetry, GPS and other options. More to come on the more complex systems.

 

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0 votes RE: ExpressLRS for RC models

Some tech. on servo motors.

Aileron position, elevator position and rudder position are controlled by servo motors. Servo motors can precisely control the positioning of these airplane controls. Servomotor are controlled by carefully-timed pulses from the receiver.

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The timed pulses is called pulse width modulation.

The servo has three wires: power, ground, plus a third wire to carry the command pulses.

"Internally, the mechanism of a servo motor uses a potentiometer attached to the rotating shaft to sense the position. It measures the width of the incoming pulse and applies current to the motor to turn the shaft, until the potentiometer indicates that the position corresponds to the incoming pulse width. This is a form of feedback control. The motor has received the desired position from the pulse width, and the actual shaft position is fed back to the circuit via the potentiometer. It compares the desired value to the actual value and drives the motor in the direction that causes actual to match desired."

 

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The servomotors are connected to the airplane control surfaces by connecting rods. This allows the aileron position, elevator position and rudder position to be controlled remotely via the radio transmitter.

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