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Rudderfeedback Sensor Robertson/Simrad RF300
#11
(2024-02-08, 06:56 PM)fgorina Wrote:
(2021-05-12, 08:58 AM)xfactor99 Wrote: Hi,

My Setting is a PI4 with OP2 and an Pi Zero-W with Tinypilot

I managed to get my Sensor RF300 working and sending NMEA0183 Rudder position to the OP2.
The RF300 a Sensor that sends a freequency (center at 3400 HZ) and a change of 1 degree gives a cahnge of 20HZ.
The sensor has only two wires 12v and GND and the produced (ripple)-frequenciy is stable for an input from 10 to 15V.
A simple circuit and an Arduin Nano Clone transforms the freequency into NMEA and send it with 38400 Baud to
the OP2 over USB.

From there it goes to the Tinypilot (WIFI) and it is visible/configurable in the Pypilot Plugin in OpenCPN on the PI4.

This is working, and y also have Rudder-limit Switches for safty ....

I would now like to get the Rudder information directly into the Arduino were Motor.ino is runing, to avoid latency ....

So my thinking is instead of phasing a NMEA sentence to the PI4, to output a (PWM) voltage the witch will serve to the Arduino, runnting  Motor.ino as input for the Rudder reference. 

My question is how do I get a reference voltage to keep the precision  ???
Should I output from the rudder-sensor-arduino two voltages, one as reference voltage and one as rudder-pos-voltage ???
How do I connect and do I have to modify motor.ino for that ???


Thanks for any input on that and
save sailing
Andreas
I have a similar situation with the same rudder feedback but have no idea how it is internal. Looking with and oscilloscope when connected to a Simrad autopilot you see a square wave with varying frequency with the rudder position and a big offset (about 12v).

I am lost about how to power the RF300 if I don't have the simrad autopilot. Perhaps feeding 12V through a resistor or inductance?. Once that extracting the signal may be done with a high pass filter.

How did you did it?
Many Thanks

Hi,
its a while ago, and I sold the that boat two years ago.

I first went wit a breadboard, feeding 12v into the RF300 and filtering the signal with a simple high-pass filter, capacitor and resistor but I dont remember the
values. Then I think I fedd that in to an OP-Amp to amplify that signal so the arduino can handle it. The arduino code reads/counts that signal/freequency and with simple math calculates the rudderangle and gives an output as required.

I might have some more infos as the code ect. and will have a look at the weekend.

Greetings 
Andreas
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#12
Thanks, that's useful. At least giving 12v to the unit dfoesn't burn it
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#13
(2024-02-09, 08:52 AM)fgorina Wrote: Thanks, that's useful. At least giving 12v to the unit dfoesn't burn it

Hi,
found a Foto from my setup

https://www.dropbox.com/scl/fi/hf94qsoxw...ymodn&dl=0

The two pairs of blue connectors at the right are 12v and the RF300
Then you have an step down converter 7805 to provide 5v to the OP Amp chip LM358 and the arduino.
The high pass filter is the condenser 104nF and the resistor 10k.

Save sailing
Andreas
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#14
(2024-02-09, 08:13 PM)xfactor99 Wrote:
(2024-02-09, 08:52 AM)fgorina Wrote: Thanks, that's useful. At least giving 12v to the unit dfoesn't burn it

Hi,
found a Foto from my setup

https://www.dropbox.com/scl/fi/hf94qsoxw...ymodn&dl=0

The two pairs of blue connectors at the right are 12v and the RF300
Then you have an step down converter 7805 to provide 5v to the OP Amp chip LM358 and the arduino.
The high pass filter is the condenser 104nF and the resistor 10k.

Save sailing
Andreas

Thanks a lot!!!
Reply
#15
All up and running, thaks to all.
Reply
#16
(2024-02-26, 02:34 PM)fgorina Wrote: All up and running, thaks to all.

Hi, I also have an RF300 sensor I'd like to connect to a microcontroller.

How did you solve this? Powering the RF300 through a resistor and reading the voltage drop across it?

Regards,
Hans
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