The fourth model in the EM1 kit is a beam balance scale with a switch mounted on the main upright. This was a nice build, with only few small surprises along the way. At rest, the vertical metal rod presses the switch in, breaking the circuit, and keeping the light turned off.
I took a detour on the road to powered speakers and remixed the cassette lid I previously designed in order to hold a panel mount voltmeter from Adafruit. I set out with a few goals:
The third model in the EM1 kit was particularly cool to build as it is the first model where the electric circuit is controlled by a mechanical component. It starts with a wheel hub whose rotation is driven by a motor. The wings on the hub are used as a cam to cyclically push a lever down and then release it; it reminds me a bit of a trip-hammer .
I’m working on adding a small powered speaker to a fischertechnik model and decided the simplest first pass would be an insert for the standard cassette that many of the older sets shipped with. I’d like to not alter the original part, so ideally, this will be a simple press-fit part which works very similarly to the stock cover. The first goal was to get a simple flat lid working.
Building the second model was a smoother process; I suspect a key reason was knowing from the start that a certain amount of improvisation was part of the process. I’m learning that, in the absence of specifics or mechanical constraints, I tend to err on the side of longer metal rods which gives some extra room for adjustment.
Growing up, I spent many hours playing with both Lego sets and fischertechnik sets. In my memory, they were functionally equivalent – just with different connecting systems and with fischertechnik having a stronger emphasis on mechanics and gears. I recently acquired some fischertechnik from that era and was pleasantly surprised by one additional difference.
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