From: tchannel@..............
Subject: Building vertical spring sensor


2.  I soldered the fitting together, using just a little solder to hold it without big, ugly, globs of solder around the joints, as it doesn't  need to hold water.
 
Hi Ted,
 
Solder it properly, leaving a fillet around the end. You need the joints to be firm and rigid
 
3.  Some joints I wanted  to rotate.  Not too loose, but loose enough to rotate with your hands. 
 
Then use compression fittings, not a push fit distorted tube - it won't be satisfactory long term.
 
 4.   At this point, the frame is done, the three adjusting leveling feet and the spring.   I still need to build the damper, the coil/magnet and mass, but so far so good.
 
Q.   My question at this point is: What is the target for the period?   The sensor is adjustable, the spring can be tightened, the hinge and arm can be lower, etc.  Any adjust I make, changes the period, if I tweak it I can get 4 seconds, but the stable position on the arm is small.  If I change the period to 3 seconds, I seem to get a larger area of stability in the arc of the arm.   By unstable I mean, If I move the horizontal spring loaded arm up or down a little it will return to center, however,  If I move it too far up it will fall toward the spring. Should I target the longest period I can get, even thought the arm is touchy and could fall up or down?  
 
If you try for a long period, the sensor will literally fall out of balance as the temperature changes. Steel springs are very sensitive to temperature. I suggest that you try for 2 to 3 seconds and then extend the period electronically, or in software.
 
Regards,
 
Chris Chapman
 

 From: tchannel@..............

Subject: Building vertical spring sensor










2.  I soldered the fitting together, using just a little solder to hold it without big, ugly, globs of solder around the joints, as it doesn't  need to hold water.


 


Hi Ted,


 


Solder it properly, leaving a fillet around the end. You need the joints to be firm and rigid


 


3.  Some joints I wanted  to rotate.  Not too loose, but loose enough to rotate with your hands. 


 


Then use compression fittings, not a push fit distorted tube - it won't be satisfactory long term.


 


 4.   At this point, the frame is done, the three adjusting leveling feet and the spring.   I still need to build the damper, the coil/magnet and mass, but so far so good.


 


Q.   My question at this point is: What is the target for the period?   The sensor is adjustable, the spring can be tightened, the hinge and arm can be lower, etc.  Any adjust I make, changes the period, if I tweak it I can get 4 seconds, but the stable position on the arm is small.  If I change the period to 3 seconds, I seem to get a larger area of stability in the arc of the arm.   By unstable I mean, If I move the horizontal spring loaded arm up or down a little it will return to center, however,  If I move it too far up it will fall toward the spring. Should I target the longest period I can get, even thought the arm is touchy and could fall up or down?  


 


If you try for a long period, the sensor will literally fall out of balance as the temperature changes. Steel springs are very sensitive to temperature. I suggest that you try for 2 to 3 seconds and then extend the period electronically, or in software.


 


Regards,


 


Chris Chapman