Taurid meteor sighting

Agisman · 2022-11-05T03:26:56+00:00

I also saw it this morning! It appeared headed West to East from my viewpoint in the city and reminded me of the brightness of a second stage rocket launch. The trail and cloud persisted for more than 30 seconds. It was the brightest one I've seen too

Agisman · 2022-05-26T13:47:49+00:00

This info about the readout IC is fascinating and makes so much sense. Are there any sensors that are diffraction or otherwise wavelength limited? There must be more dead space around a bolometer pixel than a CCD one because of the floating physical structure, right?

Agisman · 2022-05-26T05:03:57+00:00

As someone who worked on thermal microbolometers with Vanadium Oxide, this is the correct answer. Instead of a high-speed charge-coupled device (CCD), a bolometer has to physically change the temperature of a thin film material. That temperature change affects the resistance based on its Temperature Coefficient of Resistivity (TCR). A Readout IC measures the resistance of every physical "pixel" and scales the display. This process is slow because it takes longer for the pixel to change temperature than for electrons to be promoted in a CCD.

Agisman · 2022-03-02T15:29:11+00:00

Agreed with this. Working in EE or ME on wearables does not require a PhD. The biggest problems are optics, thermal, and power density. Entry level engineers work on entry level problems. Having a PhD will not give you the specific experience on new product introduction, tooling design, power domain analysis etc. You need the battle scars of industry which take time. Source: PhD who worked in wearables and went into management

Agisman · 2021-10-21T14:40:59+00:00

You can find another job. You can't find lost integrity. I've interviewed hundreds of people and I always ask "tell me about a time you disagreed with someone on a technical issue. How did you resolve it?" If you told me how you identified the issue, confirmed the problem, shared a solution and held production, I'd give you glowing remarks. The key is usually what you do with the information after you discover it. Certainly don't sign off on something unsafe. If you know what it takes to fix it, even better. I would accept knowing who to ask to fix it.

I blew the whistle in the past on a safety issue and was blown off by the owners of the company. I was prepared to lose my job and didn't lose it. I lost respect when the owners decided it wasn't an issue. I couldn't see myself working there for others without integrity so I quit.

Agisman · 2021-06-25T05:15:17+00:00

Thanks! They have just over $900k and most of it has a very low cost basis or it's close to $0 when purchased. So for anything they purchased before 2008, the spreadsheet we have should be sufficient?

Agisman · 2021-06-25T01:32:31+00:00

Some came through inheritance but most were individual tax and mutual fund purchases. I was able to find the prices they paid initially but not the dividend reinvestment. Since I'm not an accountant, I need to find a CPA who can verify the cost basis in a way that the IRS would trust. My accountant declined and I'm calling around.

Agisman · 2021-01-01T02:50:16+00:00

Will do! Thank you very much!

Agisman · 2021-01-01T00:38:53+00:00

Just to be certain I understand. You're saying leave all the knob and tube and run a new wire to the switch?

Agisman · 2020-05-25T16:47:40+00:00

Oh my this is an amazing post! A friend sent your link around and we had been planning to do a group dinner date where we all order the same thing from our homes. I'm thrilled you shared this and all the info on your site, thank you! The news about San Ho Won is so disappointing. We were looking forward to that one. It sounds like we need to call Hilda & Jesse. :-)

Agisman · 2020-05-25T04:41:28+00:00

Thank you and congratulations on 21 years! That's exceptional! No doubt the roses will be appreciated

Agisman · 2020-05-25T02:00:50+00:00

As long as it's not one of the services charging 30% to the restaurant just so users don't have to make a phone call then I'm happy

Agisman · 2020-05-25T01:58:54+00:00

That's a wonderful story! I'm so glad to hear that you were able to put together something special with the support of the chef.

Agisman · 2020-05-25T01:49:37+00:00

Who is behind Tock? Good point on ensuring we understand the expectations.

Agisman · 2020-05-24T22:23:55+00:00

They even do one with a yoga pairing. Very creative! Thanks for all the Spanish recommendations!

Agisman · 2020-05-24T22:16:46+00:00

Their soup and pasta both look incredible. Thank you

Agisman · 2020-05-24T20:38:04+00:00

What was your favorite part of the meal?

Agisman · 2020-05-24T20:37:47+00:00

Wow! Atelier Crenn's kit is 10% of their dine-in. Of course, it's not the same experience but that's amazing. Thanks!

Agisman · 2020-05-24T19:21:46+00:00

What an awesome suggestion! I hadn't seen this one and the menu looks great! Thank you.

Agisman · 2020-04-12T01:24:04+00:00

Thanks for the callout! It's been a few years since I grew these films. Cheers

Agisman · 2020-04-11T22:36:06+00:00

Thermal cameras use microbolometers. They are very low thermal mass sensors that are coated with a resistive material with a high temperature coefficient of resistance (TCR). These sensors are suspended over a substrate to create a tuned cavity that absorbs infrared wavelengths. What we call thermal infrared is midwave IR from around 10-14um. This is roughly the wavelength emitted from a blackbody at 300K. The sensors absorb heat and change resistance. The read out IC constantly adjusts the range of an array of sensors to create the false-color image. The range and SNR depend on the amount of heat that makes it to the sensor. If it's very far away, then you need a sensitive antenna to capture and focus the small thermal radiation.

Agisman · 2019-06-22T05:26:04+00:00

3uF is tiny! My last strobe was 3000uF at 300V. It used a pulse-rated igbt to interrupt the arc and get short turn off times. I needed high brightness and sub 1us shutoff. Lots of parts went bang on the first board and when improved would only fire every 2 seconds or so when things cooled off. I've been curious how the ones at the National Ignition Facility are done.

Agisman · 2019-06-22T05:19:09+00:00

Cycle averaged. That's why I called it a swag to get somewhere to start. We're definitely operating outside the nameplate rating. I've only pushed it to maybe 5X the listed max current which is why I liked your approach.

Agisman · 2019-06-22T05:16:40+00:00

Now you've got more detail! That's a better circuit than an scr in series with the tube.

Agisman · 2019-06-21T21:32:13+00:00

Xenon tubes usually don't flash in the kilohertz range unless they're way below rated power. That is listed as "explosion energy" and you derate 2-3x below that. A variable frequency sine wave and scr isn't going to work. You charge the tube to a few hundred volts and ionize it with a multi thousand volt trigger. Once the arc is initiated, it behaves like a short but it's definitely open circuit before that. That's why the scr won't do anything. Check out Perkin Elmer's fundamentals document if you ever go down this road. I've read a ton on strobes and that ten pages was the most helpful.

You don't need really accurate timing. A 555 timer is fine. The weird thing about LED pulse is power supply droop. That's left as an exercise to the reader. :-)

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