Pages: [1]   Go Down
Author Topic: Measuring Vertical Linear Movement  (Read 967 times)
0 Members and 1 Guest are viewing this topic.
0
Offline Offline
Jr. Member
**
Karma: 0
Posts: 71
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Hey,
Here's the riddle that needs to be solved: how to measure vertical linear movement?

Four sensors with a travel range of 10cm are needed.
Two sensors with a range double of this, so around 20cm.

Right now I'm using a combination of four bend sensors
http://www.sparkfun.com/products/8606
-> They have the "feel" that we need - constant, small weight.
-> They are not very stable, robust or precise.

And one of these - a drawstring linear displacement sensor
http://www.pennyandgiles.com/Draw-Wire-Linear-Sensors-pd-61,3,,.php
-> Very stable and precise, long range.
-> The "feel" is not quite right. Because of the spring in this sensor, it feels "heavy" when pulled.

So, my idea was "super smooth linear faders" with weights,
but these turn out very hard to find especially in lengths > 10cm.

Do any of you guys have any ideas for other sensors or setups to reach this goal?

So far.
All suggestions very much appreciated,
Jim
« Last Edit: May 11, 2011, 11:23:43 am by Blue_Boy » Logged

Central MN, USA
Online Online
Tesla Member
***
Karma: 64
Posts: 6889
Phi_prompt, phi_interfaces, phi-2 shields, phi-panels
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Can you share your setup picture with us? No idea what to recommend. Maybe IR sensors or sonic ranger.
Logged


Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 435
Posts: 23611
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

How about attaching a paper tab with horizontal strips that goes up & down with whatever you have, then a sensor at the base that senses the stripes going past and reports that a count or something similar?
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Silly-con Valley, Ca, U.S.
Offline Offline
Sr. Member
****
Karma: 17
Posts: 420
Lernin' to tinker
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

I was thinking liner encoder using IR as well.
Logged

10 PRINT CHR$(7)
20 GOTO 10

0
Offline Offline
Jr. Member
**
Karma: 0
Posts: 71
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Here's a picture of the current setup.
I would prefer absolute readings over encoder systems.

http://www.jimboproductions.be/server/mda/gamehub/PuppetMaster_Photo/DSC_4262.jpg

Logged

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 435
Posts: 23611
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Got a picture of it when it has moved some?
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

0
Offline Offline
Jr. Member
**
Karma: 0
Posts: 71
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Nope, sorry.
In fact, in this picture, one out of five sensors has moved already.
The drawstring out of the drawstring sensor has already been extended.
If the "playing cross" is moved higher, the ends of the flex sensors will be pulled upwards,
and bend as a result.
Logged

Pages: [1]   Go Up
Jump to: