Follow-ups

Concrete Hearth

see: http://projects.remingtons.org/2017/11/the-hearth-wants-what-it-wants.html

After turning it out of its form, we (father-in-law and a friend and I) flipped the slab over.  The surface was nice and flat, but unfortunately had some surprisingly large air bubbles.  They weren't deep, so I tried grinding them out with a polisher borrowed from another friend.  I was able to reduce them, but it left little dimples which I didn't like.  So I did a skim coat of cement slurry (which is now curing, and can be seen below).  Hopefully i can take off the high spots of that without much trouble, because i was pretty generous.

Duck Hut

see: http://projects.remingtons.org/2017/11/duck-hut.html

The ducks stay up late partying most nights (til around 9pm -- the longer light keeps them laying even as the real days get shorter).  As you can see they're also ready for Christmas:

Robot Arm

see: http://projects.remingtons.org/2017/11/mac-arduino-pi-perfboard-regulators.html

The robot arm project has made slow progress -- i connected the lowest/main arm to its motor and belt and pulleys to ensure it would work.  I also gave it a little assist with some rubber bands to reduce strain on the servo.

As you can see it works (first video is fine), but in the second video at lower angles and with weight (two pairs of pliers) the belt slips (even though its super tight and i switched to using a pulley that came with the belt).  I guess i've hit the limit of what you can pull with small timing belts.  I'll need to get some roller chain and sprockets (like on bikes) and try again.



Electronics

 The same earlier post as the robot arm mentioned a partially finished power converter block.  Here it is finished (with screw terminals [with ATX power connected] and a 3 servos attached to the 7v lines.  Works great.


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