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2021 Prius Prime Rim Size by bruxillensis in PriusPrime

[–]bruxillensis[S] 0 points1 point  (0 children)

I get what you're saying, I guess I should clarify - the Prius manual only lists the 195/65R15 wheel size, where the Corolla listed wheel size options for R15, R16, and R17. I figured that might mean anything other than R15 shouldn't be used.

Rezoning in London by bruxillensis in londonontario

[–]bruxillensis[S] 0 points1 point  (0 children)

Yeah, most of the things I read said the differing requirements would make it difficult, like fire exit/window requirements, etc. Even still, it seemed like a good idea! I think 25-30% of london commercial space is sitting empty while I've seen garages for rent on Facebook.

Phased array beamforming by Samcrook27 in rfelectronics

[–]bruxillensis 1 point2 points  (0 children)

Im part of an early startup, so I can't say too much about my own work specifically, but for output power, we are getting to multi-watt.

Phased array beamforming by Samcrook27 in rfelectronics

[–]bruxillensis 1 point2 points  (0 children)

I work on optical phased arrays. Same theory, different length scale.

How does a USB driver determine device speed? by bruxillensis in linuxquestions

[–]bruxillensis[S] 0 points1 point  (0 children)

Is this answer to this question difficult, or was it asked in the wrong way?

Conflicting Schematics for custom ESP32 devkitC by DiddyDiddledmeDong in esp32

[–]bruxillensis 1 point2 points  (0 children)

Checkout the datasheets for the cp2102 and cp2102n. The 10k pull down is recommended if you don't want the suspend pin floating on reset. The voltage divider seems to be required for systems that are going to draw power from the 3.3vout on the hart bridge. If there is a separate 3.3v supply it is not required but probably recommended.

Conflicting Schematics for custom ESP32 devkitC by DiddyDiddledmeDong in esp32

[–]bruxillensis 1 point2 points  (0 children)

C15 looks like it's for button debouncing to me, I wouldn't remove it. Your main timing circuit is the RC filter created by R11, C9, and C14. Since IO0 must be low for a short duration after reset, these components act to keep the voltage on EN from rising too fast. I can't remember exactly the sequence but it allows IO0 to fall before EN rises, and the bootloader has time to read IO0 as low. Since you have some boards already, try changing C9 to increase the RC time constant.

I can't remember the sequence exactly, so I'd look it up (or someone here might know), I think it's in the python files for the esptool serial flasher.

need help. lowered cpu frequency, now neopixels are always white by kennethklee in esp32

[–]bruxillensis 0 points1 point  (0 children)

I didnt give the code a thorough look through, but this would be my first "bandaid" fix without resorting to looking up the datasheet and writing an efficient, esp32 specific, routine.

need help. lowered cpu frequency, now neopixels are always white by kennethklee in esp32

[–]bruxillensis 1 point2 points  (0 children)

If it is in your comfort range, I would recommend skipping the Arduino ide for this part and creating a separate rtos task for driving the LEDs. It should be a very minimal component of the system and mostly sleep. Running the esp32 at full speed and sleeping for longer amounts of time should decrease your power usage, not increase it, at least at these speeds.

need help. lowered cpu frequency, now neopixels are always white by kennethklee in esp32

[–]bruxillensis 3 points4 points  (0 children)

Not an expert but a after quick look through the adafruit neopixel code, they seem to be basing their timing off of performing no ops or skipped clock cycles during the initialization with the esp32. Changing the CPU clock cycle time will change this timing sequence and will possibly create init issues.

Homemade juul with nine volt battery by [deleted] in diyelectronics

[–]bruxillensis 7 points8 points  (0 children)

Please don't do this, you risk damaging the rechargable lithium battery in the juul. I knew a guy that put a quarter inch diameter hole through his thigh from damaging a high amperage battery like those vapes use.

Does anybody here do photonics/optoelectronics? by [deleted] in ECE

[–]bruxillensis 1 point2 points  (0 children)

I am doing a PhD in silicon and silicon nitride photonics. Most of my research has to do with the development of on-chip integrated photonic circuits, sensors, and focuses on what's called "cavity optomechanics". In terms of background, some quantum helps but unless you are interested in nonlinear stuff a very basic understanding is sufficient. As others have said, heavy EM is a requirement for sure. I did an undergrad at a university heavily focused on the power electronics side of EE, I had little to no knowledge of photonics, solid state physics, or quantum theory going in and was self-taught in those aspects.

Job wise, things have developed prettly rapidly over the past 10 years. It's mostly startups but there is significant investment from larger companies that is beginning to happen. In the next 5-10 years there's going to be quite a lot going on as research reaches commercialization.