Process
Frame
 |
AFLI's physical beginnings started with his frame. The main portion of his frame was designed to be rigid and structurally solid; the design allowed for the Lego beams to be parallel with the table, an immediate correction from his predecessors. This design element allowed for stable motion modules to be installed; stable motion modules make for consistent, long-lived performance. |
|
 |
As ALFI progressed, more features were added to his frame to support elements of the motion modules. This image shows added bracing to support the motors and gear trains of the modules. |
|
 |
This image shows two main additions to the frame: the mouth and the eye cavity unit. The mouth is only attached by the connection formed between the main portion's plate and the upper portion of the mouth; later design structures cement this connection. The eye cavity is designed so the vertical beams in the cavity are perpendicular with the table; this allows for the vertical beams necessary for the eyes to be mounted. The eye cavity is firmly attached with nine pegs on each side. |
|
 |
The initial support structure left something to be desired, mainly a place to have the Handyboard rest. A separate unit had to be made to support and protect the Handyboard (not shown.) This support structure also lacked stable support; as such it was scrapped for a better version. |
|
 |
The new support structure was stable and had a built in location for the handy board. It also gave the illusion of shoulders. This structure firmly attached the mouth the the main portion. This image also shows the break beam units; these units act as the sensors for the eye lids and the eyes. |
 |
Click images to see full sized versions. |
||
Break Beam Sensors
| The break beam units are boxes that house the bream beam sensors. A break beam sensor is an infrared emitter that transmits to an infrared sensor; between these two is an object that can block the beam for a given amount of time. The unit I created has a Lego board that is spun by its connection to a motion module (such as the eye lids or the eyes.) Its spinning breaks the beam, and the amount of breaks allows ALFI's main program to figure out how far the given module has moved. After moving a specific amount, the motor for the module is turned off. The sensors weren't without issues; due to the fact I was just learning how to solder and how the sensors worked, several of the emitters used in the project (whether taken from the gargoyle project or soldered on my own) shorted out when exposed wires would touch. This problem was caught quickly and served as a valuable learning experience. | |
 |
The initial units were small and had a gear ratio of 1:8 (64/8 x 8/64 x 8/64.) The gearing involved being attached to the shaft that turned the eyes/lids, thus there was an extra 8 gear to 64 gear to negate the gearing down done for those features. The 1:8 gear ratio allowed for relatively fast spinning, but in the end, the spinning wasn't fast enough. |
 |
The units were upgraded to have an extra 8 gear to 64 gear (64/8 x 8/64 x 8/64 x 8/64) to create a 1:64 ratio. This ratio was high enough to allow for fine tune control of the modules. |
| Here is a video demonstration the eye lid break beam sensors in action. | |
Click images to see full sized versions. |
|
Light Sensors
| The light sensors are responsible for ALFI's connection to the outside world. These sensors were one of the final additions to ALFI; one light sensor sits in each of ALFI's shoulders. The sensors are placed one brick length back and are fully covered by the top of the shoulder plates. This is to cut down on the amount of light that they would pick up from above ALFI. The light sensors pick up on the presence of shadows in front of ALFI, thus detecting some kind of movement. | |
 |
 |
Click images to see full sized versions. |
|
Ear Module
| The ear module consisted of a long shaft turning two beams that were perpendicular to the shaft (these beams would later be upgraded to be more ear like, looking like rough curves.) This long shaft was initially turned by a 64 gear connected to an 8 gear driver (creating a 8:1 ratio), but this was still too fast for what I wanted. The next iteration is show in the attached video, where there are two shafts now, so the gear train now has a 64:1 ration (64/8 x 64/8.) Since the ears only have two positions, up and down, the sensors for the ears are much less complicated than those for the eyes and eye lids. The sensors consist of two touch sensors; when the left sensor is touched, the ears are marked in the down position and when the right sensor is touched, the ears are marked in the up position. The first video shows the current gearing, and the second video shows the finished module. | |
 |
 |
Click images to see full sized versions. |
|
Mouth Module
| The mouth was initially designed so a motor would drive a 24 gear to turn a 64 gear, which would turn a shaft that had two Technic angle brackets on them. These brackets create the illusion of a lower jaw. The 64/24 made for a 8:3 ratio, which proved to be too powerful, much like the ear module's initial gearing. This was later changed to be like the ear module (64:1 ration through a training of 64/8 x 64/8.) The touch sensors are similar to the ear module as well. The left touch sensors mark when the mouth is open and the right touch sensor marks when the mouth is closed. | ||
 |
 |
 |
Click images to see full sized versions. |
||
Eye Module
| The eye module has already been partially described in the frame description, so this portion will stick with details. This module's main focus is to turn two vertical beams in unison. To do this when the motor for the module can only turn horizontal beams involves using special gears (technically, the motor can be installed in such a way it can turn vertical beams, that that installation would either be less stable or overly complicated.) The motor drives an 8 gear to turn a 64 gear. This 64 gear is on a shaft that turns another 64 gear (this shaft is attached to the break beam sensor unit as well.) The new 64 gear turns two attached 64 gears. This enables the two gears to turn in unison. These two 64 gears have their own shafts that have a 24 gear each. From each 24 gear, a 24 cap/crown gear sits on top; this specialty gear enable the turning to shift 90 degrees to now turn the two vertical beams. The final gear ratio for this module is 8:1 (64/8 x 64/64 x 24/24.) These vertical beams skewer two table tennis balls with drawn on irises and pupils. | ||
 |
 |
 |
Click images to see full sized versions. |
||
Eye Lid Module
| This module's focus is to turn to beams in opposition to each other; when one moves clockwise, the other must move counterclockwise. This is achieved by having an 8 gear driver a 64 gear. This 64 gear is both attached to the eye lid break beam sensor unit and the 64 gear that turns an attached 64 gear. The connection between these last two gears is what creates the opposition turning. The final gear ratio is 8:1 (64/8.) | ||
 |
 |
 |
Click images to see full sized versions. |
||
Last Modified: May 25, 2009