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Showing posts from May, 2020

Gear investigation: Banbao Lego crane

Completion date: May 16, 2020 1. Gear ratio: 8:24:40. The bottom wheel cranking the string at speed (8/24)*(24/40)=0.2x speed of the motor. 2. The top two wheels looks like pulley system to me, but I am not sure about the spinning speed of the top wheels, the first top wheel is slower than the bottom wheeler, that I observed. 3. The beginning of the bottom wheeling action is pulling less string because the circumference is small (less string winded).  So it pulls the string faster gradually as more string is added to the circumference. 4. Note I added the rewind crank on the other side of the motor. This is the final instruction of the Banbao booklet. All the builds have been fun for me, I got to know more about gears now (though still primitive). My thoughts towards the gear mechanism is that it is not as efficient as I thought it would be. - requires many gears to do 1 simple thing - gear design has to match the many requirements of the space, distance

Gear investigation: Banbao Lego pirate ship on a swing

Completion date: May 14, 2020 1. Gear ratio is 16:24. The top spinning is at 0.66x of motor. I thought that the black gear connection just pass on same speed, but by experiment, the speed gears has the same effect just like when they are in contact. 2. By connecting the gears via the connection links, the gears turn in the same direction. 3. By connecting the gears via the connection links, it solves the distance problem between the two gears with a simple solution.  Without the connection links, many gears would be needed to get to the top. 4. I think this pirate ship is a tricky one, because one would have to tune the spinning speed to match the latency of the ship for the swinging motion to be smooth left-right-left-right. How to Give the push at the right time?  Also, the motor and the gears can get damaged when the motion is always interrupted.

Gear investigation: Banbao Lego Train

Completion date: May 10, 2020 1. Gear ratio, speed from motor to wheels is 16:40. At 0.4 speed of motor. 2. Gear ratio, speed from motor to top is 16:40=40=40=1:8=12:12. (16/40)*(1/8)*(12/12) = At 0.05 speed of motor. 3. Plane change (motor to wheels): o o o 4. Plane change (motor to top): o o o o o | | - - - (rotation on 3 different planes)

Gears investigation: Banbao Lego Moon explorer

Completion date:May 7, 2020 1. Gear ratio to the wheels is 24:40:40:24=16:16. I kind of think the wheels are going the same speed as the motor, because that 24-teeth pass off the speed to 16-teeth. 2. Gear ratio to the top black wheel is 24:40:40=24:16. (24/40)*(40/40)*(24/16)=0.9. 3. Motion planes to the wheels: | | | | | | 4. Motion planes to the top: | | | | - -

Gears investigation: Banbao Lego crawling insect

Completion date: May 4, 2020 Actually this thing looks like a crawling insect to me than a walking robot. 1.  This is 8:40 gear in terms of speed 2.  The 40-teeth gear has two roles, one as speed slowing mechanism, and also a revolver to bring axle on a circular motion. 3. The axle going in circle has an interesting effect. When the axle “draws” a circle, if you analyse the horizontal motion only on a horizontal line, it is actually not a uniform speed from left to right. It would be slow (left), faster (middle), slow (right). The same idea goes vertically: slow (top), faster (middle), slow (bottom). 4. I couldn’t be sure, but I think the bar that is on this axle (grey middle leg) is having this kind of slow-fast-slow-slow-fast-slow rhythm too. 5. The jerking motion of the grey leg looks like walking, because the leg picks up off the ground before landing on ground again. 6. The grey legs are directly attached to the 40-teeth, so this is 1st degree motion. While th

Keyboard silicon cover

Completion date: May 5, 2020 Dust gets into the keyboard and I usually buy these silicon keyboard covers. There isn’t a mould for this Rapoo keyboard, so I bought a generic one on Taobao.  Because I stand the keyboard up when I don’t use it, so the silicon cover occasionally falls down. I need a way to secure the cover from falling off. Materials - Silicon keyboard cover 14cm x 45cm (RMB$9.58/each, on a buy one get one free, so it’s around RMB$5/each) Steps 1. Cut the silicon short so it can cover all the keys. Cut the corners round. 2. With the leftover silicon, cut 2 strips 1cm x 14cm. 3. Mark at 0.5 margin.  Punch 2mm holes at the marks. 4. Cut a straight line in the middle from top hole to bottom hole. 5. Now it looks like an elastic band. Fit the keyboard through the bands at the ends to secure the silicon cover.

Gear investigation : Banbao LEGO airplane

Running on ground Motion not too smooth Completion date: April 30, 2020 Observations 1. Motor to propeller is 24=40=40:24:16.   So propeller is running 1.5 times faster than the motor (24/16=1.5) 2. Motor to wheels is 24=40=40:24. Same speed. 3. The belt can be used to pass on the same speed from one gear to another, and these gears would move in the same direction. The belt can also be used to pass the motion over a longer distance. 4. The axle can be used to pass on the same speed and same direction of the gear on the same axle. Also, the axle can be used to displace the motion to another gear on the same axle. 5. One gear can invoke motions on multiple gears. 6. Gear’s direction can change from left/right motion to become front/back motion by using a direction-changing gear.  While this is happening, the difference in gear sizes can speed up (or slow down) the next set of gear motions.