ElectroBrandon

LtSpice Potentiometer Model

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It takes about 20 seconds to put a potentiometer model in LtSpice. I have no idea why it wasn’t included. Regardless…. — Download the “Pot” folder at https://github.com/brandondrury/LTspice-Libraries — Find your C:\Users\YOUR_USERNAME\Documents\LTspiceXVII\lib\ folder— Place pot.asy in your “sym” folder. C:\Users\YOUR_USERNAME\Documents\LTspiceXVII\lib\sym\— Place pot.sub in your “sub” folder. C:\Users\YOUR_USERNAME\Documents\LTspiceXVII\lib\ sub\— Click the text tool. Select “SPICE Directive” … Read more

Blue Pill STM32 Clones Brown Out or Become Unresponsive

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The Problem:  The STM32 Blue Pill sometimes dies for no apparent reason.  On the PSU, it’s pulling 30mA and then for now apparent reason, the current draw reduces to 10mA (for the power indicator LED, presumably) and the microcontroller appears dead.  It only seems to occur when powered from a power supply to the 5V … Read more

Engineering Rule #1: Make Friends With Iteration

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Imagine you’re a young boy who worked hard all day on his sandcastle. Just as your mom calls you for dinner, a teenage jerk runs up and kicks your castle down. That feeling of loss, betrayal, and rage is only topped with the feeling that all that hard was for nothing. This is every day. … Read more

Trace Width vs Length Inductance Table for PCB Traces

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I need to know the inductance of the traces I’m creating.  It’s too slow to use the inductance calculator at All About Circuits.   Unfortunately, the equation has any given variable on both the numerator and the denominator.  I refuse to invest the brainpower to develop a rule of thumb, so I’m resorting to a table.  … Read more

Microchip 25LC256 EEPROM on STM32 Blue Pill and Arduino

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For the big, bad synth project, I needed an EEPROM.  I selected the Microchip 25LC256 from Digikey simply because it had excess capacity (256k) and was thru-hole.   (I always recommend this approach when jumping into a new arena of unpolished prototyping).  I had never worked with external EEPROM before.   It turns out that EEPROM is … Read more

Why Are All These Resistors Thru-Hole? Isn’t SMD Cooler?

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SMD is cooler….when a machine does all the work. At the prototyping phase (and assuming you don’t have all the fancier tools specific to the tiny world of SMD), SMD parts take longer to solder, often require a heat gun to remove, and offer no convenient place to hook your oscilloscope probe to. Bodge wires … Read more

Serial USARTs On STM32 Blue Pill With Arduino Code in PlatformIO

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Here’s the “Hello World” edition of getting access to USART2 and USART3 on an STM32 Blue Pill in PlatformIO using the Arduino framework. /* lib_deps = NONE # Using a library name ——– Platform.ini Settings———- [env:bluepill_f103c8] platform = ststm32 board = bluepill_f103c8 #board = bluepill_f103c8 framework = arduino upload_protocol = stlink lib_compat_mode = soft */ … Read more

Genuine STM32 Blue Pill vs CS32F103C8T6 Clone

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I’m troubleshooting a synth design and looking at the data on the SPI bus.  I have 10 STM32 clones (CS32F103C8T6) of the STM32F103C8T6 around and decided to try them out since they have the correct USB resistor. I was getting the following error in PlatformIO. Warn : UNEXPECTED idcode: 0x2ba01477 To get the clone to … Read more

bCNC Safe Z

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bCNC comes with a feature to move the spindle up to a safe z height.  If you right-click on the “Safe Z” button it looks like this. G90 G0Z(safe) The default is 3.  In my case, it was 3 millimeters.  I wouldn’t call that safe at all.  I use clamps that are much thicker/taller than … Read more

My Saga With PLCs – Part1

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I didn’t learn PLCs in school.  My gig was Engineering Physics and if the homework didn’t use Calculus to think about the atomic level, I didn’t learn it.  Granted, I didn’t learn to use Calculus to think about the atomic level, either, but that’s another rant.  So, I’m learning PLCs.  Here are some thoughts for … Read more