Author here, thanks for posting! Happy to answer any questions and would love to hear about any use cases in which folks have dynamically enabled / disabled FPU functionality throughout program execution.
Hey Arjun and Sid! I am CTO at Golioth[0], a connected device cloud platform. Just wanted to say congrats on the launch, and wish y’all the best of luck! There is lots of complexity to be addressed, and it is always great to see more folks building in this space. Happy to compare notes any time!
Good question! We wrote a few blog[0] posts[1] about the motivation for signy and how it is used in practice. The primary use case is complex devices with multiple MCUs and multi-protocol connectivity (e.g. Wi-Fi, Cellular, Bluetooth, etc.). In this context, each MCU may have different security capabilities, and manufacturing / provisioning may be simplified by storing a single set of credentials (e.g. a private key) in a single secure storage location, then using that key to generate a temporary signed URL that can be handed to the less secure domain for a scoped operation, such as downloading an asset. There are also more niche use cases, such as allowing an end user to access a private resource by generating a signed URL and sending it to a phone via NFC.
Author here -- thanks for the comments and feedback! I typically use the solder stripping technique as well when actually incorporating the inductor into a circuit. Interesting you should mention variable capacitors as I just went through the process of sourcing 5 of them (will be discussed in a future post) from Amazon, and not only were they expensive, but they also took significantly longer to ship than was originally estimated.
I am somewhat surprised that the small loops would pick up a meaningful amount of noise, though I suppose meaningful always depends on the use case and tolerances. Do you have any references for how significantly this can impact inductor performance? Or is the primary concern just the rubbing and potential shorts?
Despite ferrite core inductors and loopstick antennas being old, fairly well understood technology, I have found there to be very little in the way of hands-on experiments with tangible results available. I'm hoping to continue testing various techniques and posting about them -- you've already provided some great variations for me to test out!
Could not agree more! And yes, though due to the lack of specifications available for the ferrite rods I purchased, it ended up being more of a calculation of their permeability based on the measured inductance. I'll have another post soon that shows measuring the resonance frequency of these inductors with various types of capacitors, which is a fun exercise in parasitic capacitance and inductance.
[0] https://danielmangum.com/posts/risc-v-bytes-accessing-pineci...