[chbot] Robotics Group meeting, 5 Idris Rd, 6:30pm, Mon 19 May 2025 report

[Mark Atherton]

Hello everyone,

Good turnout with 28 attendees, and lots of huddles-of tech-talk. $42 + 
change (in gold, and flat-money) collected and transferred into the 
robotics loose-change jar (for later banking).

All sales from the trading table should go into the brown box on the 
wall, and are directly for the benefit of our host club, Christchurch 
Amateur Radio Club, NZART Branch 05.

Equipment donations are welcome for the trading table, but no CRT based 
product, printers, toner or items that are likely to be a disposal burden.

With thanks on behalf of the group,

Mark Atherton

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Don't forget SouthMach 28/29 May, Wolfbrook Arena.

Dave Jagger, architect of the ARM V7 silicon will be presenting another 
talk to us; "The Life of a Bit”. Development of silicon, tools and 
application. Possibly June, or July 2025.

Mark passed around a homemade 3D joystick assembly, with I2C interface.

He also talked about the surprise acquisition of a Synrad 75W CO2 LASER 
which runs from 30V, and would like to hear from anyone who has data on 
the associated marking head, using the (1997 vintage) Cambridge 
Technology 6450 series galvos.

Also discussed, was the design of a simple, self-powered, high-side 
current monitor capable of measuring 10A (40A peak) at 200VDC (350V peak).

Bevin gave a talk about the Python Lookup Problem, and some language 
peculiarities.

Andrew talked about low cost, high precision methods of measuring 
capacitors.

Rudy talked about some LiIon cell issues (8800mAH 18650s ?? !!). He also 
mentioned the high-power (3kW) LASER Tech Ingredients project (on YouTube).

Ash talked about progress with his PDP-11.


Interesting YouTube Videos:

Dual use connector and control. Use a rotary magnetic sensor beneath a 
3.5mm jack socket. This allows either an analog signal to be plugged in, 
or a special control knob with a 3.5mm shaft and a small magnet at the 
tip. When the knob is inserted, the socket transforms into a rotary 
control. Eurorack Knob Idea youtube.com/watch?v=dLw2QQdOLaM&t=8s

Meet Adam Savage’s ILM (Industrial Light & Magic) Supervisor. 
youtube.com/watch?v=5JRQ1z6gNYI&t=6s