....
the environment is extremely harsh, so special care is required, and the pivot point has not much room around....
Have you totally ruled out putting a compass module on one section and a separate compass module on the other section and determining relative angle via difference in compass directions? I'm guessing the compass modules could be hermetically sealed, so your only problem might be stringing a cable "across" your pivot point (though you could use a wireless solution like an Xbee, I presume). If this application is as exposed as I'm guessing it is, I bet a "simple" potentiometer solution is going to turn out to be not so simple .
ElectricAye,
I have not ruled out any option at the moment.
My compass sensors are very picky, so the idea to use them is not so appealing.
This week end a friend will go see the "machine", and test a couple of sensor, just to have a first feeling.
With all the actuators, hydraulic pumps and so on I'm not sure the compasses will offer consistent readings.
I received two other magnetic sensors today. A magnetic pot, and the melexis.
The magnetic pot has a magnet inside, is rather intriguing, easy to measure, but probably not the best option.
The Melexis is not saturating even with a supermagnet close. Moreover a home made test board is very small.
I'll post some pictures tomorrow.
Nice thing is I started investigating so many aspects new to me, at least in a micro world. Last time I did analog measurements I had 4 wires GPIB multimeters, SMU units, and so on...
Massimo
My compass sensors are very picky, so the idea to use them is not so appealing.
With all the actuators, hydraulic pumps and so on I'm not sure the compasses will offer consistent readings.
I think you will find compass sensors do not work well since the "machine" is probably made of steel and will distort the earths magnetic field.
I received two other magnetic sensors today. A magnetic pot, and the melexis.
The magnetic pot has a magnet inside, is rather intriguing, easy to measure, but probably not the best option.
The Melexis is not saturating even with a supermagnet close. Moreover a home made test board is very small.
These should work much better than the compass but may also be affected by the mass of surrounding steel. I would suggest testing them at various angles in various orientations ( N, S, E, W ) to see how the earths magnetic field affects the readings. It would also be a good idea to have a mass of steel on each end of the test assembly to simulate the machine mass.
I have a working prototype.
It uses two supermagnets to create a strong field for the sensor.
On a steel plate the readings are still consistents.
I'm using the dual sigma delta object from Ray's site.
A friend will go seeing the thing and testing it directly. Moreover this way we should be able to have more informations about dimensioins, clearance and so on, that at the moment are fuzzy.
I attached a couple of pictures fo the test system.
The sensor is inside a plastic pipe.
The magnets are attached to a bigger one, rotating around the one with the sensor.
My compass modules are too nervous, and I cannot afford to recalibrate them on the fileld.
While I like the idea to be able to place them in "safe" areas they are too sensitive and I have difficulty to obtain consistent readings.
A friend will go seeing the vehicle (and maybe making photos) this week end. This way we'll be able to verify how a sensor could be attached.
I'll keep you updated.
Massimo
A little update about the sensor.
Please find attached a couple of pictures of the machine.
Of all the solutions tested the only primising at the moment are the Melexis combined with the supermagnets, and the good old pot.
Both work with the engine running and all the related stuff.
Now the key point is finding a nice mounting solution....
Comments
Have you totally ruled out putting a compass module on one section and a separate compass module on the other section and determining relative angle via difference in compass directions? I'm guessing the compass modules could be hermetically sealed, so your only problem might be stringing a cable "across" your pivot point (though you could use a wireless solution like an Xbee, I presume). If this application is as exposed as I'm guessing it is, I bet a "simple" potentiometer solution is going to turn out to be not so simple .
I have not ruled out any option at the moment.
My compass sensors are very picky, so the idea to use them is not so appealing.
This week end a friend will go see the "machine", and test a couple of sensor, just to have a first feeling.
With all the actuators, hydraulic pumps and so on I'm not sure the compasses will offer consistent readings.
I received two other magnetic sensors today. A magnetic pot, and the melexis.
The magnetic pot has a magnet inside, is rather intriguing, easy to measure, but probably not the best option.
The Melexis is not saturating even with a supermagnet close. Moreover a home made test board is very small.
I'll post some pictures tomorrow.
Nice thing is I started investigating so many aspects new to me, at least in a micro world. Last time I did analog measurements I had 4 wires GPIB multimeters, SMU units, and so on...
Massimo
It uses two supermagnets to create a strong field for the sensor.
On a steel plate the readings are still consistents.
I'm using the dual sigma delta object from Ray's site.
A friend will go seeing the thing and testing it directly. Moreover this way we should be able to have more informations about dimensioins, clearance and so on, that at the moment are fuzzy.
I attached a couple of pictures fo the test system.
The sensor is inside a plastic pipe.
The magnets are attached to a bigger one, rotating around the one with the sensor.
My compass modules are too nervous, and I cannot afford to recalibrate them on the fileld.
While I like the idea to be able to place them in "safe" areas they are too sensitive and I have difficulty to obtain consistent readings.
Massimo
Glad to hear you're making progress.
I'd like to see how it is attached to the vehicle, so if you get a chance, post some pics of that, too.
Good luck!
I'll keep you updated.
Massimo
Please find attached a couple of pictures of the machine.
Of all the solutions tested the only primising at the moment are the Melexis combined with the supermagnets, and the good old pot.
Both work with the engine running and all the related stuff.
Now the key point is finding a nice mounting solution....
Massimo