Hi, I´m hoping to find a reliable and flexible way to measure the angle of doors/hinges. Hopefully these could be easily fitted, not be too obstructive, flexible to different door types etc. So far, thoughts I´ve had have been:
String potentiometer, gauge the rotation from the length of string the door pulls.
Laser distance sensor from the door frame pointing at the door, only works up to a certain degree of open-ness.
Potentiometer at the hinge angle, would probably be pretty to install at a hardware level, cutting holes in doors etc.
Flex sensor at the hinge.
I can´t find a huge amount about this on the internet, most are just whether the door is open or not. I want a high polling rate and high accuracy solution - for reasons.
Probably because it is not a common problem. In most cases an info whether the door is open or closed is quite enough.
May be it helps if you describe your problem in more detail. Why do you need to know a door angle?
@b707 : Synchronisation of digital and physical space
I appreciate not many people are doing it.
@cedarlakeinstruments : from 0-90 degrees would be a start, up to 120 degrees or something would be nice. I´ve been looking for string pots on amazon and stuff but really not finding much surprisingly. Do people just wire their own strings to potentiometers or what? Thanks
Mount the sensor/pot on a base and use command strips to mount the base to the frame/wall/etc. Mount the fixed end similarly on the door. Connect the two with a piece of flexible rod more or less parallel to the hinges. When done remove command strips and there are no holes/damage to mounting surfaces. MIght not be a linear signal, though.
You can DIY a string pot and a lot of people do because the commercial ones are quite expensive. @ruilviana suggests magnetic encoders which should work well. You'd probably have to mount the magnet on the center of the hinge pin and attach the sensor to the door, above it. It seems like it would be a difficult installation though.
The simplest overall solution that I can think of would be two laser distance sensors, one on each side of the door. Using two sensors should ensure coverage over the whole door swing angle and both the parts cost and installation difficulty should be low.
@awneil , thanks for your reply but I did not miss it: Syncronisation of digital and physical space. Open a physical door open a virtual door. And as stated my requirements are high accuracy and polling rate.
@cedarlakeinstruments , yes I was surprised to see hundreds of dollars listed for the string pots that I was able to find. For sure i'd rather DIYing it if possible to avoid another potential failure point but I guess this whole venture is pretty DIY...
I hadn't thought about using TWO laser distance sensors for some reason, good idea! Installation difficulty is definitely a concern for me as I'm not hugely practically skilled when it comes to saws and axes or whatever...
What are the kind of ranges that magnetic encoders are effective over? I guess it comes down to the strength of the magnet... And do they work on the strength of the field in terms of distance or the direction of polarity? Nooby question there...
