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# DIY electronic level builds

#### ballen

##### Diamond
Here is what my colleagues did with ready-made chips from the store:
I assume that these are Micro-Electro-Mechanical Systems (MEMS) sensors integrated on a chip. The last time I looked at these, a year or two ago, the best once could do, with lots of integration/averaging, was a few arcseconds of precision. You could make the resolution finer but it would not repeat.

Perhaps the integrated devices have improved. Could you tell us which chips your colleagues are using?

#### Milling man

##### Cast Iron
Could you tell us which chips your colleagues are using?
If I'm not mistaken, now (in the last about 10 years) it is possible to build a level of 5 μm/meter or a little less than 1 arc second has become possible with the help of ready-made elements. For example:
The datasheet indicates an accuracy of 0.001 degrees, but it is analog and in real use people have achieved many times greater accuracy.
If you "average" the reviews that I studied, then everything looks something like this "sensitivity of the order of 1 micron, repeatability of several microns." Of course, we need to honestly say right away that in fact it will be a device that reliably measures with an accuracy of 10 microns, and not very confidently with an accuracy of 5-7 microns. But it's a plug and play chip!

#### ballen

##### Diamond
If you "average" the reviews that I studied, then everything looks something like this "sensitivity of the order of 1 micron, repeatability of several microns." Of course, we need to honestly say right away that in fact it will be a device that reliably measures with an accuracy of 10 microns, and not very confidently with an accuracy of 5-7 microns. But it's a plug and play chip!
The SCA103 data sheet says that the noise (DC - 100Hz) is 0.0004 degrees/root Hz. So to get 0.1 arcsec =0.00003 degrees of noise means an averaging time T that satisfies 0.0004 deg/sqrt(T/sec) = 0.00003 deg which implies T/sec = (40/3)^2 = 178 so that T~ 3 minutes.

So based on the spec sheet, a minimum measurement time of 3 minutes would be required to reduce the noise by averaging to get 0.1 arcsec resolution. In practice that's too long to wait if you are using the device for measurements. If you are monitoring a building's tilt over years, that might be OK.

#### fobyellow

##### Plastic
This is a level from the Soviet Union, I don't think you will find any information about it. I haven't even been able to find instructions yet. The model is called Caliber 128. I have a photo of his wiring diagram in poor quality, but now it's all good only for a museum. On ready-made sensors, the levels turn out a little worse, but without problems - judging by the reviews. Just a few elements on the board and a cable, instead of a stack of electronic boards. Here is what my colleagues did with ready-made chips from the store:
№1, from Ukraine

№2, from Russia
Level:

thanks for the info, the commercial MEMS parts are too small, so the resolution and noise performance are not good enough. you can try paralleling several parts together, the noise performance will degrade very close to 1/squareroot N，if 16 parts parallel, the noise could be 0.0001degree, that could reach the digipas DWL9000(0.2arcsec @ <25s readtime), still cheap enough, only consumes more power
from the specs of SCA100 and SCA103, i guess the sensor part are the same, the only difference is placement, the SCA100 is XY placement, the SCA103 is X-X differential placement, the noise performance should be 1/1.414, but the datasheet gives 1/2, i ldont know why.

#### fobyellow

##### Plastic
thanks for the info, the commercial MEMS parts are too small, so the resolution and noise performance are not good enough. you can try paralleling several parts together, the noise performance will degrade very close to 1/squareroot N，if 16 parts parallel, the noise could be 0.0001degree, that could reach the digipas DWL9000(0.2arcsec @ <25s readtime), still cheap enough, only consumes more power
from the specs of SCA100 and SCA103, i guess the sensor part are the same, the only difference is placement, the SCA100 is XY placement, the SCA103 is X-X differential placement, the noise performance should be 1/1.414, but the datasheet gives 1/2, i ldont know why.
Maybe the common mode noise are cancelled, like noise from powersource and natural resonance， while the other noises are averaged

#### Milling man

##### Cast Iron
I have an idea to discuss. Heidenhain measuring probes use a light deflection circuit. This option can probably work in the level. High-resolution matrices are now cheap. Pros: No problem of electrical noise from the sensor.

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#### fobyellow

##### Plastic
I have an idea to discuss. Heidenhain measuring probes use a light deflection circuit. This option can probably work in the level. High-resolution matrices are now cheap. Pros: No problem of electrical noise from the sensor.
thats a great idea. differential light sensors are sensitive, you can even use mirror or prism to extend the pendulum even longer. it is likely easy to achieve nano-rad sensitivity, but i think the repeat and long-term-drift are still difficult

#### Milling man

##### Cast Iron
Today I looked at the Soviet-level wiring diagram, the photos of which I posted earlier.
This level has a very interesting solution! The pendulum is held in the same position by two coils and two magnets. The constant position is controlled by the LVDT. The angle of inclination will be proportional to the current required by the two coils holding the pendulum in a constant position.

#### John Garner

##### Titanium
That makes it a "force-balance" clinometer. If I recall correctly, Kearfott was one of the U S clinometer makers that really liked force-balance technology, but certainly not the only one.

#### Milling man

##### Cast Iron
I spent a little time doing the English captions for the Soviet level scheme that I talked about above. Even if you remove the right side, which is responsible for the ADC, averaging the result and displaying information, there are still a hell of a lot of elements. Compared to the Talyvel electrical circuit, this level is several times more difficult. Probably for self-repetition, the classic design of Talyvel will be the most correct prototype.

#### fobyellow

##### Plastic
I spent a little time doing the English captions for the Soviet level scheme that I talked about above. Even if you remove the right side, which is responsible for the ADC, averaging the result and displaying information, there are still a hell of a lot of elements. Compared to the Talyvel electrical circuit, this level is several times more difficult. Probably for self-repetition, the classic design of Talyvel will be the most correct prototype.
Thats pretty complex. the servoed close loop clinometer could have wider range and bandwidth than the open loop ones, thats a pretty good electronic level that you have

#### Mk1_Oz

##### Plastic
I looked into building an electronic differential level but decided that I did not have the level of electronics ability to build something that didn't have too much electrical noise.

I have been thinking for a while about the possibility of using 2 loads cells touching either side of a heavy suspended weight. As the device tilts, the load applied to one of the load cells will increase. The output of the load cell is linear vs weight applied and a simple formula using the output current and gravity could be used to determine the angle. Thoughts?

The weight would need to be very heavy to give a large enough output signal and would also need to be a good fit between the load cells. It would be easy to zero out at the current temperature and gradiant. The weight could possibly not be suspended but ride on ball bearings (too much friction?).

Something like......

#### Milling man

##### Cast Iron
but decided that I did not have the level of electronics ability to build something that didn't have too much electrical noise.
You can simply repeat Talyvel - both electrically and mechanically.
The weight could possibly not be suspended but ride on ball bearings (too much friction?).
This is definitely a bad idea. The static friction force will be enormous. Suspension is used for a reason.

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