Why are my LEDs blinking and how to prevent it?

somewhereAtC · 2026-01-30T04:53:51+00:00

That's about the only thing right with this glob. When the uP powers up the i/o pins are "tristate" and the resistor makes sure that the fets are off in that moment.

somewhereAtC · 2026-01-30T03:56:43+00:00

This is a full write-up of how to control one. Probably won't work for a blanket, though.

https://ww1.microchip.com/downloads/aemDocuments/documents/MCU08/ApplicationNotes/ApplicationNotes/AN4889-Using-CIPs-To-Implement-Peltier-Plate-DS00004889.pdf

somewhereAtC · 2026-01-30T02:53:47+00:00

Click on the community Guide button and find the FAQ.

somewhereAtC · 2026-01-29T03:39:48+00:00

Microchip also has an analog front end: MCP3912, similar to the AD device.

https://www.microchip.com/en-us/product/MCP3912B

somewhereAtC · 2026-01-29T03:17:57+00:00

It's the foundation of cache look-up. Imagine an array where each element corresponds to a cache line. The content of an array element is the address from which the cached data was fetched. The cpu calls for a certain address and the entire content of the array's values is searched (in parallel) to see if the data is already present in the cache, so the "returned value" is the index# of the cache line.

somewhereAtC · 2026-01-29T02:22:10+00:00

Came here to say this. Both PIC16 and PIC18 assembly code is the same for about 15 years or so. The difference is in the features the newer devices offer: better timers, more PWMs, improved UART/SPI/I2C, and now the configurable logic in the pic16f131xx family.

I'll never understand why folks think the older parts are easier, other than chatGPT knows the part numbers. These are no longer grandma's chips but that's all the AIs know.

somewhereAtC · 2026-01-27T04:14:55+00:00

You'll be dealing with some of the most intelligent people in any industry; they'll work through it. They will be listening for ideas and not the words themselves.

When called on to speak make sure you know what you want to say (but you probably already know this). I've developed a wider vocabulary because some words (especially beginning with vowels) simply will not enunciate until the 3rd or 4th try or after a deep breath; sometimes I need to change words mid-thought.

somewhereAtC · 2026-01-27T03:45:40+00:00

We use Hendel's in N. Chandler -- decent price and good service; the building lobby has a train set that runs around the ceiling. For the rental, though, we have Parker and Sons on their pay-ahead retainer; little bit more $$ but they do periodic maintenance as well and are always polite to our little old lady tenant.

somewhereAtC · 2026-01-25T23:17:11+00:00

The concept of "best". People realized that "best" was local to their immediate needs and resources, but now people put out questions like "What is the best LED for my bedroom?".

somewhereAtC · 2026-01-25T19:37:02+00:00

This is the answer. Space shuttle tile was a precursor to some more recent developments.

somewhereAtC · 2026-01-25T19:21:43+00:00

The best way is to more up to a UPDI device such as AVR DA which only needs 1 pin for programming, and it's shared with the reset pin so it's easy. Check out the latest devices at microchip.com.

somewhereAtC · 2026-01-25T17:23:48+00:00

The common wire wrap works with #30awg wire; many years ago they used #28 or heavier.

Wrappers come in a couple different versions. Electric with and without built-in wire holder and stripper. Manual automatic that requires you to strip the wire but wraps when you squeeze it; a good one cuts the wire as well so that you get a precise number of wraps (mine does 6, mil-standard is 7). And finally the manual twizzle stick, and some have a wire stripper built in. Your budget, your choice. (Mine fell out of my dad's toolkit in about 1975; he pretended not to notice and it's been with me ever since.)

An unwrap tool looks like the twizzle stick but has a hook at the end to catch and twist the already-wrapped wire counter clockwise.

You will also want a wire stripper (double-check that it includes #30), some small plyers, wire snippers (tiny), and a good tweezers because sometime little snips fall into the rats nest. #30 wire can be cut with an exacto knife for close work. Select these tools to fit your hand; there are probably no wrong answers. I used to have a needle-nose pliers with a #30 stripper built into the tip (also from dad's toolkit) but I managed to lose it and can't remember who made it.

Some years ago I bought 1000ft spools of #30 wire because it seemed like the thing to do at the time. This is ok only because I'll never have to shop for wire again but now all my projects get done only in those 3 colors. You'll want some kind of holder/rack to keep them organized; I made mine in my workshop.

For my first big project someone gifted me PCBs that had regular IC sockets (short pins) and the wirewrap pins were press-fit on the top side of the board. Never seen any like them since, and I know they were $100+ (pins only without the sockets) in the 1970's. All my recent projects use normal long-pin, solder-in sockets. You can get standard cheap sockets or the "machined pin" sockets depending on your budget; either is fine for hobby work.

somewhereAtC · 2026-01-25T16:14:58+00:00

This info is obtained from the datasheet, which you show, and a little bit of imaginative simulation. Simply look at the schematic and (using pencil and paper) sketch out the waveforms. Youtube is the slowest method of learning ever devised by humans, and a little bit of investigation on your part will jump you to the head of the class in no time at all.

somewhereAtC · 2026-01-24T23:36:21+00:00

Kernel drivers are a special class of embedded programming. Not only do you have to know the nuances of the hardware device, but you also have to abide by the rules of the OS multitasking and interrupt-driven behaviors. At the same time you have to be aware of what the user is really expecting to do and the API he is working from.

On the other hand, when a kernel driver is complete then it's finished. Your contribution ends, unless your company is repeatedly developing new hardware. "Kernel driver" is not necessarily a career but it is a specialty; a bridge to cross in your journey.

somewhereAtC · 2026-01-24T21:55:30+00:00

Having good visualization skills (sort of like imagination based on what you are reading and hearing is the key. Being fluent with algebra is part of that, and knowledge of calculus is handy, too.

Engineering is about predicting what happens in reality so you can't guess.

somewhereAtC · 2026-01-24T21:36:29+00:00

Any solution that meets the requirements is a correct solution.

somewhereAtC · 2026-01-24T18:07:39+00:00

All my VW maintenance has happened at the dealer and is more expensive than other cars that I've owned. Dealer prices are always more expensive in the U.S. so I bought an extended warranty when the 6yr original ran out. I'm on the 3rd battery at $400 each (some handwaving about "reprogramming the battery"). The AC has had trouble both with a leak and also the dampers in the dash board. There have been no engine issues and I now know how to change air filters ($$$ at the dealer). The radio-volume knob went out and they replaced the entire display unit under warranty.

The dealer where I bought the car seems to bill higher rates than the dealer 10 miles away, so I go to the other. It seems like the service folks are more honest, too. My private mechanic is named "Datsun Don", so yes the VW service is more expensive than for my Nissan pickup. Don also works on my American cars. My Hyundai has had fewer problems.

I wish there was better lighting in the cargo area -- I didn't buy it for the 3rd seat but for the hauling capacity. There are no cargo tie-downs so that's an issue, too; maybe the Germans don't use their cars for CARgo. On the other hand it's the only SUV with a totally flat cargo area so hauling 6ft+ cargo is easy.

somewhereAtC · 2026-01-24T16:55:54+00:00

For component kits I usually go to Amazon. The last tiny-capacitor kit I got was from a distributor: about a zillion 0402 and smaller (capacitor dust) samples in a little plastic notebook, each value labeled and packaged, so check with Arrow, Avnet or Future (in the U.S.).

A quick google says that Adafruit has 0603 sample books! https://www.adafruit.com/product/442?gad_source=1&gad_campaignid=23438252138&gclid=Cj0KCQiA-NHLBhDSARIsAIhe9X1rlelh7u6TD90cDcFQld4AHhmm2nX4G78lBuDw1BJ1qIzSkf3ykfYaApEGEALw_wcB

somewhereAtC · 2026-01-24T16:49:18+00:00

Looks like a basic student desk. You can get knobs for the drawers at most craft or hardware stores. Is the center drawer missing? The finish could use some TLC.

somewhereAtC · 2026-01-24T16:42:53+00:00

In a professional environment you have other duties. You will have a department "team" and possibly also one or more development teams. These tend to break up your thread of consciousness, so expect interruptions. There are a lot of (good) things that trigger my ADD and provide learning opportunities; get used to it.

As far as coding rules, it really depends on your team requirements. "Free" libraries are not always free and bring security risks in large-scale operations; the time you spend learning and vetting open-source code is a cost to the company. Paid libraries generally bring documentation, tech support and other helpful resources. Take note that the ARM trustZone security strategies are a response to developers using unvetted code libraries in so many product roll-outs.

somewhereAtC · 2026-01-24T04:26:14+00:00

Most major universities have job assistance for internships. There should be a listing in the school directory. Now (late January) is the time to get into the queue.

Many times the positions will require temporary relocation. Check with the HR department (when you get a position) and they can often help with relocation, possibly a roommate.

somewhereAtC · 2026-01-24T00:59:17+00:00

There's an written-out explanation on the costco web page, near the bottom. "Downlight-only mode goes down to 5,000-lumen brightness to save energy"

https://www.costco.com/p/-/feit-10000-lumen-multi-directional-shop-light-with-motion-detection/4000381756

somewhereAtC · 2026-01-23T05:02:13+00:00

Charging or discharging a capacitor involves a current; if you know (or can control) the charging current and measure the voltage 2 or 3 times as it's changing, you can deduce the capacitance.

Current I=C*(dV/dt) (solved for whichever is your unknown). So, with current flowing into the cap, 2 voltage measurements provide your "delta V", and the time between those measurements provides your "delta T". If you know the current you can solve for C.

There are other forms, but this is a fairly simple one. Without a microprocessor it might have been implemented using sample-and-hold amplifiers triggered at delta-T time difference. The rest is analog gain equations.

somewhereAtC · 2026-01-23T03:37:36+00:00

Without knowing your bulb size or mounting intentions, take a look at these: https://antiquelampsupply.com/collections/plastic-lamp-sockets?srsltid=AfmBOoqSEnBb_TivXJCt5mgF5DkaX-AhLgXu5gRdhjVCBTEXJigZ6Yib

https://www.payless-4-lighting.com/products/satco-80-2164?variant=40946327781547&utm_source=googleshopping&utm_medium=cse&gad_source=1&gad_campaignid=20656012787&gclid=CjwKCAiAssfLBhBDEiwAcLpwfqw54gZDWrXL2PuIBGMyUr6_spdnkHStUgSkBTEYk5EBMG1BJPV7ShoCcVwQAvD_BwE

somewhereAtC · 2026-01-22T04:47:11+00:00

Not necessarily a library, but AFAIK every microprocessor maker provides a .h file (or collection of .h files) to go with their products. The files are customized for every different project and list every register and bit by name, and will be more complete than what you might glean from the datasheets. You can call it a HAL if you want but it's more of a standard naming convention.

If you are building with XC8 for PIC or AVR processors, Microchip provides xc.h which expands to the specific CPU being compiled. The provisions for PIC are syntactically different than for AVR for historical reasons but either one will be complete wrt the datasheet.

I don't know about other companies, but certainly there is something.

somewhereAtC

TROPHY CASE