/[gzz]/manuscripts/Control1/poster.rst
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revision 1.65 by humppake, Mon May 5 20:39:10 2003 UTC revision 1.66 by tjl, Mon May 5 20:39:25 2003 UTC
# Line 93  controllers by providing a simple design Line 93  controllers by providing a simple design
93  controllers out of commodity parts, without requiring electrical or  controllers out of commodity parts, without requiring electrical or
94  mechanical engineering experience.  mechanical engineering experience.
95  The components that suit our purposes best are LEGO bricks and  The components that suit our purposes best are LEGO bricks and
96  optom  optomechanical computer mice.
97    
98  .. from the end user point of view, several spesific  .. from the end user point of view, several spesific
99     controllers have been tricky to use simultaneously before USB     controllers have been tricky to use simultaneously before USB
# Line 121  optom Line 121  optom
121          - a way to do user interface device research on EXTREMELY          - a way to do user interface device research on EXTREMELY
122            limited budgets            limited budgets
123    
     - LEGO has already published a robotics invention series called  
       Mindstorms, which also contains bricks with touch and light  
       sensors and a central unit to control them. Even the central unit  
       alone  
       is quite expensive and the existing sensors  
       are not accurate  
       enough for controller use, we look them forward with interests.  
   
124      - advantages:      - advantages:
125                
126          - LEGO bricks          - LEGO bricks
# Line 164  REF: the prototypes of the tiltable PDA Line 156  REF: the prototypes of the tiltable PDA
156       was measured by having the fishing line go through a grid wheel       was measured by having the fishing line go through a grid wheel
157       in the mouse with small weigtht at the end maintaining tension.       in the mouse with small weigtht at the end maintaining tension.
158    
159    - LEGO has already published a robotics invention series called
160      Mindstorms, which also contains bricks with touch and light
161      sensors and a central unit to control them. Even the central unit
162      alone
163      is quite expensive and the existing sensors
164      are not accurate
165      enough for controller use, we look them forward with interests.
166    
167  REF: Mindstorms-using articles &c  REF: Mindstorms-using articles &c
168    
169  [fitzmaurice95bricks]_  [fitzmaurice95bricks]_
170    
171     - using physical Lego-size bricks as controllers for applications  - using physical Lego-size bricks as controllers for applications
172       on a large horizontal display surface     on a large horizontal display surface  
173     - a Lego brick sorting experiment shows how two hands are  - a Lego brick sorting experiment shows how two hands are
174       used flexibly in parallel   used flexibly in parallel
175    
176  Graph: axes: price, DOF  Graph: axes: price, DOF
177    
# Line 192  controllers has been the interfacing of Line 192  controllers has been the interfacing of
192  the optomechanical mice.  the optomechanical mice.
193    
194  .. figure:: required.jpg  .. figure:: required.jpg
195     :width: 7.5cm  :width: 7.5cm
196     :label: figrequired  :label: figrequired
197    
198     The non-LEGO parts and tools required for a controller.  The non-LEGO parts and tools required for a controller.
199     A USB mouse would be preferred to the PS/2 mouse  A USB mouse would be preferred to the PS/2 mouse
200     shown in the picture, since several can be connected  shown in the picture, since several can be connected
201     to a computer simultaneously as separate input sources.  to a computer simultaneously as separate input sources.
202    
203  .. figure:: mouseopen.jpg  .. figure:: mouseopen.jpg
204     :width: 7.5cm  :width: 7.5cm
205     :label: figmouseopen  :label: figmouseopen
206    
207     The mouse, opened with the screwdriver. The screwdriver  The mouse, opened with the screwdriver. The screwdriver
208     will not be needed after this step.  will not be needed after this step.
209    
210  .. figure:: mousemechanism.jpg  .. figure:: mousemechanism.jpg
211     :width: 7.5cm  :width: 7.5cm
212     :label: figmousemechanism  :label: figmousemechanism
213    
214     The mechanism of the mouse: the mouse ball, which rotates  The mechanism of the mouse: the mouse ball, which rotates
215     from contact with the underlying surface, rotates  from contact with the underlying surface, rotates
216     the two axles whose motion is then detected.  the two axles whose motion is then detected.
217    
218    
219  .. figure:: optomechanism.jpg  .. figure:: optomechanism.jpg
220     :width: 7.5cm  :width: 7.5cm
221     :label: figoptomechanism  :label: figoptomechanism
222    
223     In optomechanical mice, the motion of the axles is detected  In optomechanical mice, the motion of the axles is detected
224     by the IR light gate whose beam is cut by the slitted disk.  by the IR light gate whose beam is cut by the slitted disk.
225    
226  Figures [ref-figrequired]_ - [ref-figoptomechanism]_ explain  Figures [ref-figrequired]_ - [ref-figoptomechanism]_ explain
227  the internal mechanism of optomechanical mice,  the internal mechanism of optomechanical mice,
# Line 238  additional materials or tools, but the a Line 238  additional materials or tools, but the a
238  affected: the gate missed a large fraction of the events.  affected: the gate missed a large fraction of the events.
239    
240  .. figure:: wheelmechanism1.jpg  .. figure:: wheelmechanism1.jpg
241     :width: 7.5cm  :width: 7.5cm
242     :label: figwheelmechanism1  :label: figwheelmechanism1
243    
244     The principle behind the current version of  The principle behind the current version of
245     our interface between the optomechanical mouse and  our interface between the optomechanical mouse and
246     LEGO pieces: driving the mouse axles by a rubber LEGO tyre.  LEGO pieces: driving the mouse axles by a rubber LEGO tyre.
247     A smooth tyre (Bricklink part no 132-old)  A smooth tyre (Bricklink part no 132-old)
248     works even better, but they are currently  works even better, but they are currently
249     in short supply.  in short supply.
250    
251  The third and so far final solution is to use the mouse's own  The third and so far final solution is to use the mouse's own
252  mechanism, simply driving it using a LEGO rubber tyre  mechanism, simply driving it using a LEGO rubber tyre
# Line 259  LEGO mechanism shown in Figs. [ref-figpr Line 259  LEGO mechanism shown in Figs. [ref-figpr
259  [ref-figpressmechanism1]_.  [ref-figpressmechanism1]_.
260    
261  .. figure:: pressmechparts.jpg  .. figure:: pressmechparts.jpg
262     :width: 7.5cm  :width: 7.5cm
263     :label: figpressmechparts  :label: figpressmechparts
264    
265     The LEGO parts for the driving mechanism  The LEGO parts for the driving mechanism
266    
267  .. figure:: pressmechanism1.jpg  .. figure:: pressmechanism1.jpg
268     :width: 7.5cm  :width: 7.5cm
269     :label: figpressmechanism1  :label: figpressmechanism1
270    
271     The driving mechanism assembled. The mechanism is attached  The driving mechanism assembled. The mechanism is attached
272     to the LEGO framework by the long axle; the driving tyre  to the LEGO framework by the long axle; the driving tyre
273     is on one end of the 1x5 liftarms and  is on one end of the 1x5 liftarms and
274     a towball for attaching a rubber band  a towball for attaching a rubber band
275     at the other.  at the other.
276     The rubber band is used to pull the towball upwards,  The rubber band is used to pull the towball upwards,
277     which in turn presses the tyre downwards.  which in turn presses the tyre downwards.
278     The force is easily adjustable by adjusting the other  The force is easily adjustable by adjusting the other
279     end of the rubber band.  end of the rubber band.
280    
281  With the pressure mechanism, it is simple to build a housing  With the pressure mechanism, it is simple to build a housing
282  for the lower part of the mouse case and place the tyre holders  for the lower part of the mouse case and place the tyre holders
# Line 286  is not shown in the these images). Line 286  is not shown in the these images).
286    
287    
288  .. figure:: framestart.jpg  .. figure:: framestart.jpg
289     :width: 7.5cm  :width: 7.5cm
290     :label: figframestart  :label: figframestart
291    
292     The beginnings of the housing for the mouse case.  The beginnings of the housing for the mouse case.
293    
294    
295  .. figure:: framedrivers.jpg  .. figure:: framedrivers.jpg
296     :width: 7.5cm  :width: 7.5cm
297     :label: figframedrivers  :label: figframedrivers
298    
299     The driving mechanisms (using a slightly different version  The driving mechanisms (using a slightly different version
300     than the one depicted in the previous figures)  than the one depicted in the previous figures)
301     attached. After the towballs are attached  attached. After the towballs are attached
302     to rubber bands for pressing the tyres downwards slightly,  to rubber bands for pressing the tyres downwards slightly,
303     motions from the LEGO axles are accurately translated to mouse  motions from the LEGO axles are accurately translated to mouse
304     X and Y motions.  X and Y motions.
305    
306  On the software side, the Linux kernel is able to  On the software side, the Linux kernel is able to
307  pass events from each USB mouse to a different virtual device  pass events from each USB mouse to a different virtual device
# Line 324  The handles can be used to control zoom Line 324  The handles can be used to control zoom
324  focused node and the peripherally shown nodes.  focused node and the peripherally shown nodes.
325    
326  .. figure:: loomcontrol.jpg  .. figure:: loomcontrol.jpg
327     :width: 7.5cm  :width: 7.5cm
328     :label: figloomcontrol  :label: figloomcontrol
329    
330     A fully functional controller prototype, with two  A fully functional controller prototype, with two
331     absolute arm controls and a wheel control. All three  absolute arm controls and a wheel control. All three
332     controls have enough friction  controls have enough friction
333     to retain their position.  to retain their position.
334    
335  We must stress that  We must stress that
336  this constoller is still very much work in progress;  this constoller is still very much work in progress;
# Line 353  differs from general joystick game contr Line 353  differs from general joystick game contr
353  by preserving its position  by preserving its position
354    
355  .. figure:: joystick.jpg  .. figure:: joystick.jpg
356     :width: 7.5cm  :width: 7.5cm
357     :label: figjoystick  :label: figjoystick
358    
359     A 2D joystick-like controller built from LEGO bricks as  A 2D joystick-like controller built from LEGO bricks as
360     a proof-of-principle.  a proof-of-principle.
361     There is no force returning the joystick to its  There is no force returning the joystick to its
362     center position in this design, but if desired,  center position in this design, but if desired,
363     that could easily be added (although in that case simply  that could easily be added (although in that case simply
364     purchasing a commodity  purchasing a commodity
365     game controller would be easier).  game controller would be easier).
366    
367  Practical tips  Practical tips
368  ==============  ==============
# Line 388  Mechanical looseness is a different matt Line 388  Mechanical looseness is a different matt
388  the following design rules:  the following design rules:
389    
390  - No frictionless pins.  For controllers, the frictionless pins are next to useless  - No frictionless pins.  For controllers, the frictionless pins are next to useless
391    except in special circumstances due to their looseness.  except in special circumstances due to their looseness.
392    
393  - A high gear ratio right after the gear attached to the  - A high gear ratio right after the gear attached to the
394    control stick is vital  control stick is vital
395    to alleviate the looseness in gears after that.  to alleviate the looseness in gears after that.
396    
397  - Axles used in gear trains must be supported at several points,  - Axles used in gear trains must be supported at several points,
398    far enough from each other.  far enough from each other.
399    
400  - All moving  - All moving
401    joints should be designed  joints should be designed
402    symmetrically, using e.g. 3-long pins with friction.  symmetrically, using e.g. 3-long pins with friction.
403    This is similar  This is similar
404    to taking the numerical derivative of a function  to taking the numerical derivative of a function
405    
406  .. raw:: latex  .. raw:: latex
407    
408      $f(x)$  $f(x)$
409    
410    at  at
411    
412  .. raw:: latex  .. raw:: latex
413    
414      $x$  $x$
415      
416    as  as
417    
418  .. raw:: latex  .. raw:: latex
419    
420      $(f(x+\epsilon/2) - f(x-\epsilon/2)) / \epsilon$  $(f(x+\epsilon/2) - f(x-\epsilon/2)) / \epsilon$
421    
422    instead of  instead of
423    
424  .. raw:: latex  .. raw:: latex
425    
426      $(f(x+\epsilon) - f(x)) / \epsilon$  $(f(x+\epsilon) - f(x)) / \epsilon$
427      
428    
429    
430  Handles  Handles
# Line 440  As an example, an octagonal Line 440  As an example, an octagonal
440  handle is shown in Fig. [ref-figoctagonal]_.  handle is shown in Fig. [ref-figoctagonal]_.
441    
442  .. figure:: octagonal.jpg  .. figure:: octagonal.jpg
443     :width: 7.5cm  :width: 7.5cm
444     :label: figoctagonal  :label: figoctagonal
445    
446     A rugged and relatively comfortable octagonal  A rugged and relatively comfortable octagonal
447     handle built from slopes and inverted slopes.  handle built from slopes and inverted slopes.
448    
449    
450  With some more effort, ergonomic handles of any imaginable shape  With some more effort, ergonomic handles of any imaginable shape
# Line 453  LEGO bricks with air-hardening Line 453  LEGO bricks with air-hardening
453  modelling paste, as in [ref-figpaste1]_.  modelling paste, as in [ref-figpaste1]_.
454    
455  .. figure:: paste1.jpg  .. figure:: paste1.jpg
456     :width: 7.5cm  :width: 7.5cm
457     :label: figpaste1  :label: figpaste1
458    
459     An ergonomic handle implemented using  An ergonomic handle implemented using
460     air-hardening modelling paste. The handle was  air-hardening modelling paste. The handle was
461     molded directly to the left hand of one of our research  molded directly to the left hand of one of our research
462     group's members.  group's members.
463    
464    
465    
# Line 475  Pros: Line 475  Pros:
475  - easy to build  - easy to build
476  - reusable parts  - reusable parts
477  - USB -> can attach as many as we want, simple to use  - USB -> can attach as many as we want, simple to use
478    programmatically e.g. in Linux  programmatically e.g. in Linux
479  - taps to several scientists' hidden background in LEGO building.  - taps to several scientists' hidden background in LEGO building.
480  - fun, motivating  - fun, motivating
481    
# Line 483  Cons: Line 483  Cons:
483    
484  - weak (legos may break apart)  - weak (legos may break apart)
485    
486      - requires careful construction  - requires careful construction
487    
488          - see tips section      - see tips section
489    
490      - gluing parts  - gluing parts
491    
492  - mechanical looseness  - mechanical looseness
493    
494      - some inevitable  - some inevitable
495    
496      - humans used to some  - humans used to some
497    
498      - can be alleviated to a great degree by careful construction  - can be alleviated to a great degree by careful construction
499    
500          - see tips      - see tips
501    
502  - relatively big size  - relatively big size
503    
504      - size has already reduced and will probably still reduce by new  - size has already reduced and will probably still reduce by new
505        inventions for connecting mouse's optomechanics mouse to handles    inventions for connecting mouse's optomechanics mouse to handles
506    
507  - requires calibration  - requires calibration
508    
509  - having to explain to budget counters purchases of LEGO sets with  - having to explain to budget counters purchases of LEGO sets with
510    interesting names (or bricklink purchases)  interesting names (or bricklink purchases)
511    
512  Most of the cons are still acceptable for prototypes, using LEGO bricks for  Most of the cons are still acceptable for prototypes, using LEGO bricks for
513  prototyping won't rule out the possibility to create "real" controller  prototyping won't rule out the possibility to create "real" controller

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