My invention stories

Completion date: October 2, 2021 My retractable badge holder’s string is thinning and would be broken soon.   I cut it short.  Pull the rotten part out with a tweezer. Insert the string from this end.  Tie a knot.   Reinstall the silver triangle back. 

Completion date: June 7, 2020 The Lego Power Functions Idea book.  Vol 1: Machines and Mechanisms #169 I followed the e-book version on this one.  The result is a walking motion of the legs swings in opposite directions.  The motor is too fast and I didn’t take a video on this one.

Completion date: Jun 12 2020 Steps 1. Trace the star shape onto the fabric.  Double over the fabric.  Apply pins to secure the edges.  Cut out. 2. Install a platform on the sewing machine.  3. Whenever I need to turn the fabric I place the needle down on the fabric before turning the fabric.  Sew until I get a 15 cm opening. 4. Flip the fabric inside out and put the foam filling inside the star cushion.  Bind off the opening by hand sewing. My daughter requested for a star cushion.  I recycled filling of a foam-type cushion into this one.  This was the first time I used a platform.  The table was not long enough but I put something underneath to support the platform.  She was pleased with it though it wasn’t pink as she originally requested.  Below in the picture was her little hand!

Completion Date: May 24, 2020 Work from home has given me chance to use my DIY table (35cm*50cm) ever more than before.  I feel great, but I realize the fact that I don’t have enough space if I want to work on my iPad at the same time.  I bought this mini drawer tracks so I can create this space. Material:  - 10 inch (25cm) keyboard drawer tracks, 1 pair (Taobao, RMB12.5) - 24*36cm wooden board (left over I have at home) Steps: 1.  Stretch the keyboard tracks to full extent.  Fit the wooden board to the end of the track and mark the holes with pencil. 2. This is 2.5mm drill bit.  Drill pilot holes to the marked holes.  Do the same for the other side. 3. Take my table top out and flip upside down.  Fit the keyboard drawer and trace the outline and mark the holes with pencil.  Re-verify the keyboard outer edge aligns in parallel with the table top’s outer edge. 4. Drill the holes ...

Completion Date: May 31, 2020 After I finished with Banbao gears collection, I search on web for other building instructions.  I came across the Klutz Lego and saw the picture that I just built from looking at it.  It was quite easy and fast, however, I would like to convert it to vertical winding, but I don’t know how yet.  So here is the original one. Gear ratio is 40:8=40:24 = (40/8)*(40/24)=8.3 times faster then the hand-winding motion.

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, dist...