Boom angle sensor

[mr_byte31]

I am making a control system for a very old Crane.

I build the full system using PLC.
The only sensor I couldn't find easily was the angle sensor. The crane use "Boom angle sensor". I need to order it from Alibaba. Its price exceeds $100. I would like to find a low cost solution.

I tried to substitute this sensor with a normal variable resistor and I added a small weight to it. it looks like a pendulum. The weight is always going down due to gravity and when the crane go up or down, the angle of  the resistance change. The solution works for some days and then the resistor is damaged because of the vibration in the machine !

The error in reading the angle shall not exceed +1 or -1 degree (requirement)

I thought to use MPU5060 as angle sensor. I watched some videos on youtube but it seems not very sensitive and I am not sure about how much it needs calibration.
I found a program on my Asus phone that make the phone acts as angle sensor but I was confident that this solution is not very reliable.

I was asking if someone know a more convenient solution.

[pickit2]

look on e-bay for level box.
I'm sure you could easy convert it to an input device.

[leptro]

Hello,
Have a look on sensitec AL798AMA-AE available from RS.

They have analog output..  so will need some computing routine to use it.

I have never used them.


Regards.

[hosmis]

SCA610 series

https://www.aliexpress.com/item/Freeshipping-SCA610-SCA610-C28H1A/32818735416.html?spm=2114.search0104.3.46.21eb2eabLzI4au&ws_ab_test=searchweb0_0,searchweb201602_3_10065_10068_319_317_5733915_10696_10924_453_10084_454_10083_10618_5733715_10920_10921_10922_10307_537_5729315_536_5733815_5730615_10059_10884_5734015_10887_100031_321_322_10103,searchweb201603_51,ppcSwitch_0&algo_expid=03cba539-b1b8-4169-8227-f1d49114ec2e-7&algo_pvid=03cba539-b1b8-4169-8227-f1d49114ec2e


https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20181119040442&SearchText=sca610

[mr_byte31]

look on e-bay for level box.
I'm sure you could easy convert it to an input device.

It is nice idea but no interface to the device.

SCA610 series

https://www.aliexpress.com/item/Freeshipping-SCA610-SCA610-C28H1A/32818735416.html?spm=2114.search0104.3.46.21eb2eabLzI4au&ws_ab_test=searchweb0_0,searchweb201602_3_10065_10068_319_317_5733915_10696_10924_453_10084_454_10083_10618_5733715_10920_10921_10922_10307_537_5729315_536_5733815_5730615_10059_10884_5734015_10887_100031_321_322_10103,searchweb201603_51,ppcSwitch_0&algo_expid=03cba539-b1b8-4169-8227-f1d49114ec2e-7&algo_pvid=03cba539-b1b8-4169-8227-f1d49114ec2e


https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20181119040442&SearchText=sca610

I think this is accelerometer , I think MPU5060 still have such thing but this is not reliable !

 

Hello,
Have a look on sensitec AL798AMA-AE available from RS.

They have analog output..  so will need some computing routine to use it.

I have never used them.


Regards.

I will check about this.

[b555b]

Maybe you can use a magnetic rotary position sensor (for exemple from AMS https://ams.com/angle-position-on-axis ).
Either by placing a magnet and the sensor on the rotation point of the boom, or by replacing your variable resistor pendulum by a fixed sensor on the boom in front of a magnet whose rotation is controlled by the pendulum.

[hosmis]

SCA610-C28H1A  no accelerometer , this is inclinometer very stable chip vibration resistant
https://www.mouser.com.tr/datasheet/2/281/s47e-522718.pdf
analog + digital output
±30°, ±0.5 g
±90°, ±1 g

[fpgaguy]

ok since you covered the obvious, there's also things like this which are cheaper
external magnet encoder
https://www.digikey.com/product-detail/en/ams/AS5304A-ATSM/AS5304A-ATSMCT-ND/5960948

https://www.digikey.com/product-detail/en/honeywell-aerospace/HMC1512-TR/342-1010-1-ND/334165

or with I2C
https://www.digikey.com/product-detail/en/ams/AS5601-ASOM/AS5601-ASOMCT-ND/5032390

[mr_byte31]

Sorry guys, I still didn't get it.

you provide me with sensors for detecting how far is the object.
I still don't know what to do with such thing.

The previous sensor was placed as seen in attached figure(check red arrow).

[hosmis]

Arrow indicator on the sensor
Position according to the bum axis
It gives 0-5 volt analog output.
You can measure it with a voltmeter or PLC.
or with SPI interface

https://www.murata.com/~/media/webrenewal/products/sensor/gyro/selectionguide/sca61t_inclinometer.ashx

[Wizpic]

Would something like this may do, looks simple to interface, I think you would have to do the maths may be
https://uk.farnell.com/vishay/981he0b4wa1f16/sensor-hall-effect-0-5-analog/dp/1713988?gross_price=true&CATCI=aud-294759717834:pla-57456883570&CAAGID=14406255429&CMP=KNC-GUK-GEN-SHOPPING-1713988&CAGPSPN=pla&gclid=Cj0KCQiA_s7fBRDrARIsAGEvF8R4Gm-VjLSwKX-fEPixMPBT_OZTd2wWa8jFrcp6o0V6AhKXx1l18dEaAhx9EALw_wcB&CAWELAID=120173390000291988

[pickit2]

MEMSIC accelerometers and tilt sensors

the Level Box has 3 main ic's
1 micro
2 lcd driver
3 tilt ic

try buying the tilt ic cheaper than a Levelbox

Mr Byte you always want a full solution, we try to guide you.
Not do the job for you, you have to do that.

[Wizpic]

Yeah I have been looking at those too, this project interests me and sounds an interesting project to be working on, reminds me of the project I was involved in a few years back when I built and designed a bespoke lift for a Wurlitzer to lift it out of the ground and automatically stop once night was reached, had to follow strict guidelines to meet the  CE requirements plus it had to be really smooth and run from the mains using a dc motor and controller.

How accurate do you need the angle measurements need to be?
The only reason I ask could you use a few limit switches where you could lay them out say 10;30,50,70,90 degrees the only draw back to that is you would not know where it was in between the limit switches.
Like others mentioned accelerometer chip may be the way to go.
I may have a solution we use a few different types of angle sensors on our equipment but it all depends on your max angle you need to detect, I think these give a 0-5v ouput and know for a fact they give very stable ouput as they are used on scissors and booms machines, I could see about powering one up and compare them against max angle you require and see if that helps and I can let you know the make and you may be able to get one

[techneo]

Or you can use a position encoder and processing its output using an 8-bit Atiny85. These position encoders give you the direction and amount of rotary travel which can easily be converted into angles.


https://www.alibaba.com/product-detail/Guaranteed-Quality-Proper-Price-Position-Motor_60538628144.html?spm=a2700.7724857.normalList.5.4bca5b8eZdEDPJ&s=p





-techneo

[mr_byte31]

MEMSIC accelerometers and tilt sensors

the Level Box has 3 main ic's
1 micro
2 lcd driver
3 tilt ic

try buying the tilt ic cheaper than a Levelbox

Mr Byte you always want a full solution, we try to guide you.
Not do the job for you, you have to do that.

Not really but I am searching for an answer that I can understand and implement.

I mentioned that I already looked for MPU5060. doesn't it have the same concept for ICs mentioned in the thread? Maybe some of them.
I am just afraid of calibration issues and precision !

Posted on: November 22, 2018, 03:55:14 03:55 - Automerged

Yeah I have been looking at those too, this project interests me and sounds an interesting project to be working on, reminds me of the project I was involved in a few years back when I built and designed a bespoke lift for a Wurlitzer to lift it out of the ground and automatically stop once night was reached, had to follow strict guidelines to meet the  CE requirements plus it had to be really smooth and run from the mains using a dc motor and controller.

How accurate do you need the angle measurements need to be?
The only reason I ask could you use a few limit switches where you could lay them out say 10;30,50,70,90 degrees the only draw back to that is you would not know where it was in between the limit switches.
Like others mentioned accelerometer chip may be the way to go.
I may have a solution we use a few different types of angle sensors on our equipment but it all depends on your max angle you need to detect, I think these give a 0-5v ouput and know for a fact they give very stable ouput as they are used on scissors and booms machines, I could see about powering one up and compare them against max angle you require and see if that helps and I can let you know the make and you may be able to get one

max error shall be in range of +1 or -1 degree this is the challenge for me !

Posted on: November 22, 2018, 03:56:45 03:56 - Automerged

Or you can use a position encoder and processing its output using an 8-bit Atiny85. These position encoders give you the direction and amount of rotary travel which can easily be converted into angles.


https://www.alibaba.com/product-detail/Guaranteed-Quality-Proper-Price-Position-Motor_60538628144.html?spm=a2700.7724857.normalList.5.4bca5b8eZdEDPJ&s=p





-techneo

It is not clear how I use this IC on the crane ?
I know the concept used in the IC. Mainly it shall be connected inside a motor or stuff like this.


Posted on: November 22, 2018, 03:58:45 03:58 - Automerged
The hall effect sensors will not be a suitable solution for my project.
Those sensors depend on a moving object that cause change in the magnetic field.
if the sensor is closed and the angle was changed due to a certain reason, the sensor will not be able to tell what is the true angle.

the boom angle sensor will be able to adapt to any change even if the machine is switched off since the weight is always pointing to the ground ( gravity direction)

[pickit2]

you say you looked at the MPU5060
it will give you the boom angle, also a sideways tilt angle.
I use them in an alarm system, sensor.


https://www.bing.com/videos/search?q=mpu6060+youtube&&view=detail&mid=900CE00329373392935C900CE00329373392935C&&FORM=VRDGAR

[b555b]

Posted on: November 22, 2018, 03:58:45 03:58 - Automerged
The hall effect sensors will not be a suitable solution for my project.
Those sensors depend on a moving object that cause change in the magnetic field.
if the sensor is closed and the angle was changed due to a certain reason, the sensor will not be able to tell what is the true angle.
the boom angle sensor will be able to adapt to any change even if the machine is switched off since the weight is always pointing to the ground ( gravity direction)

Have you looked at the sensors of post #5. These are not simple hall sensors, but a combination of several hall sensors with some internal processing that is able to give you the absolute orientation (angle) of a magnet relative to the sensor with up-to 14-bit accuracy. Even if you turn off the system, rotate the magnet, turn the system back on, the sensor will gives you the new angle of the magnet. Replace the potentiometer of your original experiment with such a sensor fixed to the boom and a magnet at the rotational axis of your pendulum.

[hosmis]

MPU5060  MPU9055  MMA8451  ADXL345  etc...
not suitable for professional work
at least not suitable for crane
maybe BNO055
not available on vibrating device
you cannot compensate

[mr_byte31]

Have you looked at the sensors of post #5. These are not simple hall sensors, but a combination of several hall sensors with some internal processing that is able to give you the absolute orientation (angle) of a magnet relative to the sensor with up-to 14-bit accuracy. Even if you turn off the system, rotate the magnet, turn the system back on, the sensor will gives you the new angle of the magnet. Replace the potentiometer of your original experiment with such a sensor fixed to the boom and a magnet at the rotational axis of your pendulum.

Many thanks for the idea. This is something to consider but it will not be on the first list. sorry to say that.
to perfectly add a magnet and a sensor on an old crane is not easy task but it is feasible.
I am afraid that the magnetic pattern will have much noise due to the different metal parts of the machine.

The challenge is that those machines are most of the time dirty, vibrate and several maintenance can make things vary.

The boom angle sensor seems like the perfect solution since it doesn't matter with all variations on the machine !

I am trying to see a possible solution using variable resistance and a load !
 

Posted on: November 22, 2018, 11:00:50 11:00 - Automerged

you say you looked at the MPU5060
it will give you the boom angle, also a sideways tilt angle.
I use them in an alarm system, sensor.


https://www.bing.com/videos/search?q=mpu6060+youtube&&view=detail&mid=900CE00329373392935C900CE00329373392935C&&FORM=VRDGAR

MPU5060 is not a good solution for industrial products. The error is high

[pickit2]

Did you read the data sheets, you can get rid of errors, your not going 100mph in moving the jib.
well the one by MEMSic MX2500E is in their list of devices for crane boom arms.
and is used in the Levelbox.   you don't get it. I said try the levelbox as you only need to connect two wires and ground to break out into the real world. but then you just skipped what was said.

back in the day cranes had a plumb bob, and the person who operated it knew what they were doing.

[hosmis]

Dual Axis Digital Angle level + SVRS232 USB or SV-BT bluetooth adapter

https://www.aliexpress.com/item/DXL360-Digital-Protractor-Inclinometer-Dual-Axis-Digital-Angle-level-box-with-SVRS232-USB-or-SV-BT/32876176557.html?spm=2114.search0104.3.15.5e1c363eXi9TEs&ws_ab_test=searchweb0_0,searchweb201602_3_5734715_10065_10068_5734615_319_5734815_317_10696_10924_453_10084_454_10083_10618_10920_10921_10922_10307_537_5729315_536_5730615_10059_10884_10887_100031_321_322_10103_5734515,searchweb201603_51,ppcSwitch_0&algo_expid=0110c292-93d8-4726-9fb1-ea7a44c18f79-2&algo_pvid=0110c292-93d8-4726-9fb1-ea7a44c18f79

[snowman]

I worked with boom vehicles before. You need something solid and something you can trust. Maybe because of I'm old school, I prefer not to use fancy sensors. But I know they are reliable too.

you can look into this one. Its simple, you know what's inside and design/change as you wish. Its using any step motor as rotary encoder sensor.

https://www.instructables.com/id/Using-Stepper-Motor-As-Rotary-Encoder/

https://blog.arduino.cc/2018/07/16/stepper-motor-utilized-as-a-rotary-encoder-with-arduino/

There are angle sensors and positions for arduino. They use them to get axis angles of drones. They are cheap and they can obtain multiple axis angles at the same time.

[kreutz]

As you are dealing with a mechanical device you should also consider the possibility of losing sensor power while the boom is in an arbitrary position. By using incremental type encoders you should not trust the last known position in order to start calculating a boom new position, since the mechanism could have moved while the power to the sensor was off. In that case it is imperative to have an absolute type sensor or a power on routine to move the boom into a limit sensor with a known position (home position).

[CocaCola]

or a power on routine to move the boom into a limit sensor with a known position (home position).

But, this can't be automatic since you are outside a controlled environment...  The last thing you want is to be hovering a load or even an empty boom having a sensor power glitch or even just turn the machine on and all the sudden have the boom moving without any user control or consent...   Best to have a calibrate on power option, but only with operators consent to initiate the calibration...

Honestly at the end of the day, if there is a $100 over the counter device designed for just this application, it's really silly IMO to try to re-invent and take on the liability of an unproven design, to save literally a few dollars...

[hosmis]

Inclinometers (SCA series ) does not need calibration.
Power on or off, always works according to gravity.

[Parmin]

A bit late into this discussion,
I have made a stabilized camera boom crane (that was used in filming MadMax movie) using accelerometer a few years ago.
Shouldnt be too difficult.

Posted on: November 25, 2018, 06:08:29 18:08 - Automerged
When the camera and their support gears and harness are over 200 kg lifting from a 5 meters boom from a truck moving at 70 km/h I think it is not too far off from a crane.
Thinking of it, one of the requirement is also going down 45 degree from the horizontal line to shoot from tire axel level.
But hey , who am I to argue  

Back then I have also posted similar question here in Sonsivri and was given quite a few good advices.

[Signal]

A have some some thoughts and doubts.
1) I do not get how could be justified a CRANE and 100$ saving by not buying a proper device.
2) Doing it yourself properly probably will rise a price of your device higher.
3) If an angle between boom and chassis is required then using accelerometers (as well as inclinometers based on accel.) will cause an obvious mismatch
4) Vibrations could be effectively compensated by mechanical and digital filtration, I believe.
5) I'd avoid giving any directions what to do with devices for CRANE to a person that is not able to handle it himself (in accordance with standards and certificates in that area).

[an007_rld]

You can use 2 barometric pressure sensors (today is possible measure a 10cm hight difference) on top of crane and one on bottom and based on the difference you can calculate the inclination; it's not sensitive to vibration...

[vern]

very good, a totally new approach. But you get only the angle between chassis and boom, you don't have the angle relative to earth's surface.

[Parmin]

Should not stop only at putting the inclinometer on the boom, should put one on the truck as well for relative angle to the ground and read the difference.

[CocaCola]

Should not stop only at putting the inclinometer on the boom, should put one on the truck as well for relative angle to the ground and read the difference.

Although I agree, if one is using a barometric pressure sensors all around with a +/- of 10cm for both I don't believe you can resolve to 1 degree of accuracy reliably as the error compounds across both measurements, especially true since the truck's length to height isn't enough to mitigate the +/- 10cm reading tolerance of the sensors well enough...

[an007_rld]

I can give you another one: I'm thinking... what if you run a pipe full with a fluid along the crane arm and place a pressure sensor on the bottom side. The sensor measure the weight of fluid and the exercised force vary based on gravity direction relative to pipe.

For the 1'st idea you can eventually check the following pressure sensor:
https://www.digikey.ca/en/product-highlight/m/measurement-specialties/ms5637-pressure-sensor

[vern]

now it's getting really weird.
There should be a new topic: weird solutions to simple problems.

[Signal]

now it's getting really weird.

It's not so simple to be weird ;)

[snowman]

here's another one...

https://www.aliexpress.com/item/Angle-sensor-0-360-degrees-0-5V-output-full-circle-no-dead-12bit/32611741633.html?spm=2114.search0604.3.2.70755936ixpE9v&s=p&ws_ab_test=searchweb0_0,searchweb201602_1_10065_10068_319_10059_10884_317_5730611_10887_10696_100031_321_322_10084_453_10083_454_10103_10618_10307_538_537_536_5729311,searchweb201603_51,ppcSwitch_0&algo_expid=4857aa03-f1c0-4356-b7e9-7843265a6198-0&algo_pvid=4857aa03-f1c0-4356-b7e9-7843265a6198

[Wizpic]

Please keep this to helping with sensible ideas, If you have not got anything to add or sensible then don't reply.

Signal have you got any further with all the ideas and suggestions that have been made ?

If this continues I will be forced to lock the topic as it does not seem to be going any where.

[Parmin]

Although I agree, if one is using a barometric pressure sensors all around with a +/- of 10cm for both I don't believe you can resolve to 1 degree of accuracy reliably as the error compounds across both measurements, especially true since the truck's length to height isn't enough to mitigate the +/- 10cm reading tolerance of the sensors well enough...

Why would you use barometric sensor?
Accelerometers are great for angle measurement.
A lot are sensitive enough for even less than a quarter of a degree angle against the horizon.

Posted on: 14 December 2018, 06:07:03 - Automerged
The gyroscopic feature of most accelerometer is sensitive down to 200 counts per degree

[CocaCola]

Why would you use barometric sensor?

I wouldn't and that was what I was pointing out...  For clarity, I should have also quoted an007_rld who suggested the barometric sensor as my reply was mostly towards that sensor approach and how it wouldn't resolve to the degree of accuracy, especially when combined with my agreement with you that there should be sensors on the boom and vehicle...

As I said previous, if there is a $100 device already commercially designed for this application, I would not waste my time re-creating the wheel and assuming liability vs just spending $100 on the existing device and calling it a day...

I hope that clarifies it...