This forum uses cookies
This forum makes use of cookies to store your login information if you are registered, and your last visit if you are not. Cookies are small text documents stored on your computer; the cookies set by this forum can only be used on this website and pose no security risk. Cookies on this forum also track the specific topics you have read and when you last read them. Please confirm whether you accept or reject these cookies being set.

A cookie will be stored in your browser regardless of choice to prevent you being asked this question again. You will be able to change your cookie settings at any time using the link in the footer.

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Analog motor sensors
#1
Is it possible to connect openplotter to resistive motor sensors?  would be great to get coolant temp, oil pressure , turbo pressure and so on. and stndard tank sensors.

Most sensors operate in a 0-500 ohms range , 10-180 being most common in europe , while  240-30 ohms is most common in the US

here are the faria sensor values:http://faria-instruments.com/site_manuals/IS0085E.pdf

Both 2-wire sensors and one wire (resistance to ground) sensors should be supported , but either one would do.


Come to think of it; what about making a Rpi zero signalK motor interface??


Keep up the great work.

  .manitu
Reply
#2
(2016-03-24, 07:15 PM)manitu Wrote: Is it possible to connect openplotter to resistive motor sensors?  would be great to get coolant temp, oil pressure , turbo pressure and so on. and stndard tank sensors.

Most sensors operate in a 0-500 ohms range , 10-180 being most common in europe , while  240-30 ohms is most common in the US

here are the faria sensor values:http://faria-instruments.com/site_manuals/IS0085E.pdf

Both 2-wire sensors and one wire (resistance to ground) sensors should be supported , but either one would do.


Come to think of it; what about making a Rpi zero signalK motor interface??


Keep up the great work.

  .manitu

At this time, it does not.  There have been discussions of selecting an Analog to Digital converter, but it hasn't made it to the top of the priority list yet.
Reply
#3
I did a little reordering of requested features and analog sensors jumped to the top Smile
Look here: http://forum.openmarine.net/showthread.php?tid=4
Reply
#4
Moved this thread to features requests forum
Reply
#5
Great. got me a Rpi2 yesterday , to tinker with until I get my Rpi3.

A friend who works with electronics, who gave me the Rpi2 , offered to make me a 3 dollar analog sensor interface.
I'ts basically a atMega 328 dim, a reset switch, pull-up resistors and a few lines of code.
It has 4 analog inputs if we use I2C , 6 if we use SPI. (8 if we use a different atmega 328 format)
+ 4/4 digital I/O's..

The resistance of the sensor would need to be scaled , either in the atmega , or preferably in openplotter so you get support for any resistive sensor. the scaling itself is a single line of code , dividing the ref voltage over the pull-up and the sensor resistance.

Could something like this be supported directly in Openplotter? we could allso use a bigger atmega for more I/O's.

Wichever ADC solution you choose as your reference , I  will buy one , just to have the same hard ware as others.

however, a intuitive way to take analog input voltages from SPI/I2C/whatever source , scale them , and turn them into NMEA/signalK values, and the possibilities are unlimited.

 .manitu
Reply
#6
There is a guy working on an ADC board with 2 MCP3008 (16 analog inputs) connected by SPI openplotter interface which will provide variable voltage dividers:

http://foro.latabernadelpuerto.com/showp...count=1576

But a standalone arduino connected by SPI could be a complementary solution and could use the same openplotter code/interface.

I think that is time to organize a little all the work that is being done around openplotter, so let me some days to try to create workgroups and try to coordinate them.

thanks!
Reply
#7
Hola marineros.


I've been researching the sensor input issue , and different possibilities have emerged.
The MPC3008 looks good and has been used a lot with the Rpi already.

I stumbled over Emile Cantin's blog , he uses a ardunio to read sensors, do all math , and send the data in SignalK format!
It looks like it should be easy  to do an engine mounted interface for most engines with analogue sensors, sending SignalK data over your preferred bus.

We could even make a code library for the different engine brands, or if someone wants to make some interfaces and sell them , they could.
I think this could help both Openplotter , and the SignalK revolution.

One problem though...
If we use openplotter , replacing original gauges, there's no problem.
If we mount extra sensors , obviously , no problems.
But if we want to get data to openplotter , from original sensors , while keeping the original panel , problems emerge... 

First , the original gauges are fed with 12-14,4 volt, 100-300 ohm pull-up's, so the signal voltage goes higher than 3,3 or 5 volt. 
Next, In a traditional dual instrumentation , you use senders with half the resistance , as you now have two pull-up resistors in paralell.

So , what I need to do to get this working is to read each sensor's voltage, without affecting it, then scale it down to something the ardunio or Openplotter ADC can read. I guess I'll just have to assume the ref voltage is close to 14,4v most of the time the engine is running.

Any ideas?

Another Rpi project worth checking out is the Homegrown Marine project. Specially his direct LOG input.

Keep up the good work. Openplotter , and the signalK crew, is going to change Boating as we know it!

  .manitu
Reply
#8
Hello Members.
I have been using OP for a few months and playing around with all its functions. Very impressed with the stability and ease of use.
I was going through some of the threats and noticed the same request that I was wondering about; Interfacing to the engine.

Instead of trying to adapt to existing sensors, I was thinking to add additional sensors to my engine. This was I can keep my old (40 year old) analog gauges and add a complete independent monitoring system.
I happen to have a perfect solution already ready for this. For one of my other projects (eosweather.ca) I developed a PCB to get sensor data from weather sensors. This board can be used for Engine sensors (temp, pressure, rpm's etc) as well. All sensors would be 0-5VDc or 4-20mA. After collecting the analog data, the PIC microcontroller can send an NMEA data string to the OP!
The nice thing about this PCB is that it fits directly onto the GPIO connector of a RPI!

I will start getting some sensors and over the next few months will make this work.
Does anyone have the NMEA0183 data string for engine data. I found $--RPM but that only contains RPM data...
Also, it would be nice to have some gauges to display the data

Thanks
Henk
Reply
#9
(2016-07-26, 01:16 PM)henker Wrote: Hello Members.
I have been using OP for a few months and playing around with all its functions. Very impressed with the stability and ease of use.
I was going through some of the threats and noticed the same request that I was wondering about; Interfacing to the engine.

Instead of trying to adapt to existing sensors, I was thinking to add additional sensors to my engine. This was I can keep my old (40 year old) analog gauges and add a complete independent monitoring system.
I happen to have a perfect solution already ready for this. For one of my other projects (eosweather.ca) I developed a PCB to get sensor data from weather sensors. This board can be used for Engine sensors (temp, pressure, rpm's etc) as well. All sensors would be 0-5VDc or 4-20mA. After collecting the analog data, the PIC microcontroller can send an NMEA data string to the OP!
The nice thing about this PCB is that it fits directly onto the GPIO connector of a RPI!

I will start getting some sensors and over the next few months will make this work.
Does anyone have the NMEA0183 data string for engine data. I found $--RPM but that only contains RPM data...
Also, it would be nice to have some gauges to display the data

Thanks
Henk

Hi Henk,

First of all sorry for not answering the email you sent me few days ago. Too much work and few time, as usual...

That sounds really great. I would be glad to help. OpenPlotter can also deal with all kind of sensors but an intermediate arduino/PCB could simplify the wiring and make all safest.

The bad news is that NMEA 0183 doesn't have sentences for most engine data. You could use XDR sentences but there is not a standard for this sentences and every device uses its own ID and settings. Since this is a common issue for all projects, OpenPlotter included, we are working hard to fully implement the new open protocol Signal K to OpenPlotter. Signal K specification allows to deal with all kind of data. This is how OpenPlotter will work:

Inputs
  • All NMEA 0183 inputs are converted and stored in Signal K model  (serial, network)
  • All NMEA 2000 inputs are converted and stored in Signal K model (serial)
  • All the digital and analog sensors connected to OpenPlotter generate Signal K data directly (1W sensors, I2C sensors, GPIO sensors, SPI sensors) and stored in the Signal K model.
  • All the notifications get by MQTT, SMS or OpenCPN are stored in the Signal K model.
  • OpenPlotter calculate new data (true wind, rate of turn...) and generate Signal K data directly.
outputs
  • Built in apps to show instruments from signal K model in your remote devices.
  • Send Signal K data to any specific external app.
  • OpenPlotter actions system uses Signal K values as triggers to run multiple actions.
  • Built in app for build NMEA 0183 from Signal K data (not a converter, a builder to send custom NMEA 0183 data, ex. you could send the XDR data that OpenCPN or any devices likes)
  • Signal K to NMEA 200 converter to send data to your NMEA 2000 network.
So we recommend you to send Signal K data to communicate with OpenPlotter. If this is not possible, OpenPlotter could convert NMEA 0183/2000 data to Signal K but you will not be able to find the right sentences to send most sensors data. I could guide you to choose the right Signal K values to send and the right format.

What do you think?

More info:

http://signalk.org/
A similar project:
https://bitbucket.org/R_P_Ryan/enginemonitor/wiki/Home
https://bitbucket.org/R_P_Ryan/enginemon...ersion_2_0
A tutorial to send Signal K from arduino:
http://blog.emilecantin.com/web/sysadmin...art-1.html
http://blog.emilecantin.com/web/sysadmin...art-2.html

I will reply your email as I have some time, sorry again Smile
Reply
#10
For engine temperature I use the excellent ds18b20 sensors then openplotter, otter outputs mqtt so I can keep an eye on things remotely in the cockpit with an android tablet reading the data over wifi.

Sent from my SGP511 using Tapatalk
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)