In my previous post, I did a little woodworking on the scale. In this post, I start designing a 3D printed part that will keep the top of the scale centered on the bottom.
Ever since I measured the center of gravity of the top plywood circle, I’ve been puzzling through how to make sure that center of gravity stays centered on the bottom part of the scale. Without some sort of connection between the top and bottom plywood circles, the top will inevitably slide over time, messing up all the center of gravity calculations. On the other hand, if this connection between the top and bottom has much vertical friction, it will take some of the load of the scale, throwing off the weight calculation.
In my previous post I soldered the weight scale parts to a proto-board. In this post, I design and 3D-print the part that keeps the Load Sensors from slipping.
The Load Sensor is an oddly-shaped thing that has a few tricky constraints: the T-shaped part in the middle must be free to bend downward (my wooden mounts take care of that), and I don’t want it to slide out of place horizontally or tilt off of its position when I’m putting the top plywood piece on the scale.
Here’s how advertising works today, glossing over a lot of detail:
A web site, like CNN.com, offers advertising space
You experience the medium, say by browsing to CNN.com
Part of that experience is an advertisement
The site records the fact that you saw a particular ad
The site charges the advertiser of that ad.
Great, no? Advertising behaves like it has for ages: a medium gets income by essentially renting out part of the medium. And for online ads, when you click on an ad, an advertiser pays a lot.
Here is the weakness: if you are only exposed to an ad, but don’t click on it, the advertiser’s value of you, as an individual, seeing that ad is tiny.
Along comes https://flattrplus.com/. Flattr Plus’ model is simple: you pay a website directly for the ads you block – and it’s cheap because ads you don’t click aren’t worth much.
Think about that for a minute: the advertiser wants to pay the website to show you ads; you want to pay the website to not show you ads. Who will win? Is not seeing an add worth more than seeing one? If it is, online advertising just died. Right in front of your eyes.
In my previous post I described how to use long break-away headers, and started soldering the circuit together. In this post I finish transferring the scale circuit from the breadboard to a protoboard, and do a quick test mount of the circuit on the plywood scale base.
A reminder: I found that the Load Cell Amplifier was (by design) so sensitive to changes in resistance that just touching the resistors on my solderless breadboard caused large changes in the Amplifier output. So I wanted to solder all the parts down.
Thanks to @feraldata I happened to be reading Elizabeth King’s piece on a 16th Century monk automaton. The article describes the automaton as having “duende”, loosely translated as “soul” – that is, there is something surprisingly profound (or upsetting) about this simple robot. That observation reminded me of the Laughing Sailor automaton that was popular as a Edwardian seaside amusement: drop in a coin, and the seated sailor in the glass booth would laugh and rock back and forth.
Sounds simple, non-threatening, and maybe even silly, doesn’t it? Yet when I saw a Laughing Sailor automaton up close, at Wookey Hole, I found it had something uncanny in its behavior: the all-too-real eyes flick malevolently to the left and right; the face is disturbingly half way between a smile and a grimace, and the not-quite-human rocking to and fro suggests the fellow is far too amused by some joke that may turn out to be on you!
A Laughing Sailor of one sort or another has appeared in various movies, always in the form of a malevolent robot whose laughter comments on the macabre situation. I’m not surprised – the little guy creeps me out.
Et proiectus est talpa – "and the mole was cast out"