#008 – LCSC, JLCPCB Assembly, and School Python

It was a strange week. I have my first “real” job since 2003. (I’m talking full-time job.) It was a struggle to get this podcast out. I’m feeling my grip on my my reality from just 5 days ago slip away. Regardless, I was able to maintain my usual, low standards. I had plenty to talk about. I spent about a day finding a switch on LCSC. I learned a ton about the JLCPCB Assembly process, and it turns out that school may have been onto something in Python.

#007: Incredible Synth Filter, SMD MIDI Optocouplers, and Woes of Production

Pocast 007 : Incredible Synth Filter, SMD MIDI Optcouplers, and Woes of Production

Last week’s video:
LTspice Potentiometer Download and Install

— Filters
—– Scowering the web
——- found interesting schematic
——- built it up. It acted weird.
——- I simulated it in LT Spice
——–I It was still weird. It wasn’t a LPF at all, but some kind of goofy resonant peak thing.
——–Later on, I re-read the description and it said, “Fake LPF”. Sigh.
— No forum schematics? Fake news?

— Incredible video on synth design
——-DIY Synth Design Tutorial Series – 003: Analog Filter and Power Supply
——-https://www.youtube.com/watch?v=efnBC_zZduA
———- This guy knows his stuff. He gets into the real design. the.room.dis.connect

—— Introduces LM13700 transconductance amplifier
———- We all know what an RC filter is?
————– The R is little more than current control.
————– The cap is a bucket and the “current” is the flow of water to fill up that bucket.
————— What if we wanted to control R on the fly?….potentiometer
—————— What if we wanted to control a stereo 4-pole filter. We’d need an 8-gang potentiometer.
———- This led the search for a VCR (voltage controlled resistor)
—————I knew a MOSFET’s Rds does this, at least to a certain degree.
—————This would require some real chops
———- Enter the LM13700 transconductance amplifier.
—————— Essentially a VCR… voltage in controls current out.

Filter conclusion: Transconductance amplifiers allow us to control filter frequency.
———— allows creative options as CV

Back to LM13700
— About $1 in quantity
— Plenty of them on Digikey and LCSC
— A mono, four pole filter needs 2.
—- The datasheets “Application Information” is sensational.

SMD Optocoupler For MIDI TLP2361
https://calcium3000.wordpress.com/projects/teensy-midi-interface/
This guy made a super helpful blog post showing how he made his Teensy MIDI board using TLP2361 opto coupler

#006: A Big Mess of Electronics

This episode had no big theme, but many small ones.

Topics
— I’m redoing this podcast because of noise and why that is GREAT!
— I finally hooked a MIDI controller to Reagan Revenge.
— Last week’s Youtube video was Can You Reflow Solder In The Kitchen? https://youtu.be/ioDRD-fo0PY
— Fear of selecting wrong platform (comment on Embedded.FM)
— A programmer without a power source
— Going back to Python
— Talk about e-gas
— Knipex Tools lead catcher plies to keep you from shooting your eye out
— Finish the code before you start the “real” hardware

#005: Arduino Programming In Pro Products?

Does the Arduino programming language have any place in professional products? This is a topic that comes up frequently for people that have a cool idea and feel the pull of product design but feel like maybe they are wimping out if they were to choose Arduino over Embedded C. Embedded C certainly has performance benefits, but that comes with costs of its own….TIME! In this podcast, I rant and rave incoherently about when Arduino programming should be used and should not be used when developing a product. I also talk about wool socks, heating pads, and dinosaur eggs.

#004 – PlatformIO For Arduino

The creators of the Arduino IDE made decisions to “simplify” their software. Essentially, they designed the Arduino IDE to have minimal barriers to entry on the first use. Unfortunately, this omits features that would be critical to almost anyone on their third use of the tool. In this episode, I ramble about why I love the PlatformIO IDE for VSCode when programming on the Arduino framework.