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rruark

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rruark
·3 năm trước·discuss
A cheap toaster these days will use a toaster ASIC rather than a general purpose microcontroller or timer. PT8A2514 [1] is one example. Another surprising type of ASICs I've come across are vape ASICS [2].

[1]: https://www.diodes.com/assets/Datasheets/PT8A2514A.pdf [2]: http://robruark.com/other/Teardowns/Vape_ASIC/vape_asic.html
rruark
·4 năm trước·discuss
Starlink for RVs: $135/month. A premium over the standard product, but far less than $500/month for business service.

https://www.starlink.com/rv
rruark
·4 năm trước·discuss
I built a USB power back using these cells a couple months ago after finding out that disposable vapes have rechargeable batteries. A friend had already taken the cells out of several of his own vapes; I don't know how I'd feel about taking apart ones that I found on the street.

http://robruark.com/projects/power_bank/power_bank.html
rruark
·4 năm trước·discuss
Using multiple events for a single bit seemed pretty inefficient to me when I built a random number generator based on radioactive decay [0].

I ended up toggling a bit every time an ADC was sampled. When an event was detected (rising edge triggered with hysteresis), the bit associated with the rising edge sample becomes the output random bit. I think this is acceptable as long as the ADC sampling rate is >> the expected event rate, but I haven't done the analysis to prove this to be the case. The result is one random bit per event (unless events pile up in which case only the first event counts).

[Edit] It looks like the author did the same thing per their comment!

[0] http://robruark.com/projects/random/random.html
rruark
·4 năm trước·discuss
While impractical and not cost effective, having a bunch of bikes connected to the grid and randomly producing power would have no more of an impact on the grid than flicking a 60W light bulb on and off.
rruark
·4 năm trước·discuss
We may be seeing the highest nominal price for wheat in US history, but we are nowhere near the highest inflation adjusted price. The price of wheat in 1866 was $2.06/bu [0]. That is $36.43/bu in 2022 prices.

In times of famine, prices have of course been higher. Just for fun, the rider of the black horse in the book of revelations prices a quart of wheat at one denarius (a typical days wage at the time). If you go by the 4.4g silver content of the coin, that comes out to $3.64 per quart or $135/bu.

[0] https://www.ers.usda.gov/data-products/wheat-data/
rruark
·5 năm trước·discuss
These MOT based spot welders transfer far more heat to cells than capacitive discharge welders. This can result in the damage to heat sensitive components inside the cells which is the same reason that soldering isn't recommended for lithium cells.

To get around those issues, I built a capacitive discharge spot welder for tabbing lithium ion cells a couple years ago: http://robruark.com/projects/welder/welder.html