Simrad RF300 Rudder feedback unit

[weegiemann]

Hello out there, I am wondering if anyone can help me, I have a spare RF300 rudder feedback unit which I was wanting to use to make an led based rudder indicator . I really need this as a stand alone unit that I can use day or night to see at a glance my rudder position, this is particularly the case when coming off the top of a wave at night. So my intention was to use the RF300 feedback unit interfaced to an arduino to read it and then display the Rudder position on a simple bar of LED lights coloured green and red. I know that the RF300 is a frequency based unit but I dont know how to operate it or indeed how to wire it into an Arduino, Is there anyone out there in the OpenMarine universe who has already done this or knows how to operate a RF300 rudder feedback unit that would be willing to assist me here.
Many thanks 
weegiemann

[holgerw]

Hello WEEGIEMANN

As this is an CAN Device it is suitable easyly into an NMEA2000 System.

For an Arduino there are easier Ways to go. Use an cheap Rudder Indicator, which has only the mechanic and an potentiometer inside. The middle pin goes to one of the arduino analog input pins and the other 2 pins to GND and Vcc (3 or 5V depends of your arduino HW). You could use your available Rudder Sensor as it has also an Potentiometer inside and throw the rest of the electronics away (or better send it to me ;-). So better leave this Thing together for an later upgrade of your system to N2K.

But i like your Idea to have an LED Night indicator. Maybe you are able to use an cheap DIY Indicator with an Poti and some Mechanical. Potis have linear or logaritmic courves (the latter is uses for loudness in audio) so buy an linear type. The resistor is not so important 1k to 100k should be okay.

have Fun sailing.
Holger

[weegiemann]

Huild a waterprroof housing for it olger,

Tks for your reply, I have made a rudder indicator using a pot but it was not so successful, the pot was electrically very noisy and having to build a waterproof housing for it added to the complications. The lazerette where the rudder shaft is located is a pretty damp place. I was hoping to use the RF300 as the electronic components are already in a suitable housing built to withstand harsh conditions, I thought initially the RF300 was basically a pot but it only has 2 wires and a screen coming out of it and no matter what combination of wire I used I cannot detect a changing resistance. Some more investigation into the RF300 suggests that there is a frequency generator inside it and the frequency changes in accordance with the Rudder position. The base or set frequency corresponds with the mid position of the sensor and the frequency changes either up or down based on the position of the indicator arm, Ideally I would like to use it in the manner it was designed for but I need an internal wiring diagram or even better a circuit diagram that I could use to achieve my aims, If you have any more information on how I can use it I would well appreciate it if you could share it with me, thanks again for your reply. Regards Graham

[holgerw]

There are frequency Counters libraries for pi and arduino. Try them.

[fgorina]

Huild a waterprroof housing for it olger,

Tks for your reply, I have made a rudder indicator using a pot  but it was not so successful, the pot was electrically very noisy and having to build a waterproof housing for it added to the complications. The lazerette where the rudder shaft is located is a pretty damp place. I was hoping to use the RF300 as  the electronic components are already in a suitable housing built to withstand harsh conditions, I thought initially  the RF300 was basically a pot but it only has 2 wires and a screen coming out of it and no matter what combination of wire I used I cannot detect a changing resistance. Some more investigation into the RF300 suggests that there is a frequency generator inside it and the frequency changes in accordance  with the Rudder position.  The base or set frequency corresponds with the mid position of the sensor and the frequency changes either up or down based on the position of the indicator arm, Ideally I would like to use it in the manner it was designed for but I need an internal wiring diagram or even better a circuit diagram that I could use to achieve my aims, If you have any more information on how I can use it I would well appreciate it if you could share it with me, thanks again for your reply. Regards Graham

I am in the same situationm. Have the software for the frequency reading done and working in an ESP32, also it saves the rudder position to a SignalK server and outputs a PWM signal that after filtering may be used to input to the Motor controller.

My problem now is connecting the unit. It has only 2 wires and testing them in the Simrad autopilot found they have 12v (for power) and the signal. I looked a it with an oscilloscope and it was a "big" sqare wave. Will have to confirm as I am not now in the boat and don't remember exact values.

That means there is some isolation from the power supply. I would like to get the schematics of the device so I don't burn it and may be able to create a good interface.  

I am creating a Github Plarformio project to get the software and will add all the information I get.

The url is https://github.com/fgorina/RF300-Converter. Hope it helps

[ShieldShadow]

You'll need to figure out how to read the RF300's signal and interpret it with Arduino. Once that's sorted, displaying rudder position on LEDs should be easy.