Author Topic: From no parts to decent stockpile, best approach?  (Read 206951 times)

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Offline Codealot

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Re: From no parts to decent stockpile, best approach?
« Reply #225 on: March 14, 2020, 04:06:21 am »
By the way, I got this assortment kit for the starters: https://www.amazon.com/Interstellar-Electronic-Assortment-Transistors-Potentiometer/dp/B07D1HVZ15
Do you think I wasted my money?
 

Online wizard69

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Re: From no parts to decent stockpile, best approach?
« Reply #226 on: March 18, 2020, 02:43:57 am »
By the way, I got this assortment kit for the starters: https://www.amazon.com/Interstellar-Electronic-Assortment-Transistors-Potentiometer/dp/B07D1HVZ15
Do you think I wasted my money?

Wasted Money, that is for you to determine.   The good thing about this kit is that they give you counts of individual sizes of resistors.   That is the good thing, the bad thing is that some of those may not be used for a long time.   Like all things it depends upon where you interests goes.

So while it isn't a bad kit, I would have preferred a kit that was a little heavy in resistors used for biasing diodes and such.   

As for being worth you money, i think the simple answer here is could you buy all of this for less?   Most likely yes because it costs money to create the kits.   Sometimes it is worth it to do so to avoid the hassle of DIY.
 

Offline dbctronic

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Re: From no parts to decent stockpile, best approach?
« Reply #227 on: March 26, 2020, 12:43:00 am »
This thread has picked up some good posts since I was last on.

If you think you will be cobbling up circuits that require precision component values, for example to make fairly accurate oscillators, get some more of the low end resistor values (say, 10 to 470 ohm). Put these in series with nominal value resistors to make precise values, which is called hand synthesis. You may also want to get some more low value capacitors to put in parallel with nominal value units, but it's not as easy to determine what values to use unless you have a capacitance meter, or the ability to measure a circuit's output and you just find trimming caps by trial and error.
For further precision, I also recommend a cheap or freeware 2D CAD program for making project front panel artwork that includes custom calibrated scales for potentiometers. With these two techniques, I can get 1% accuracy using standard cheapo pots. Start with a scale that reads from 0 to 100, and mark it with desired final markings by experimenting with the pot. Redo the scale artwork to match what you get.
 

Offline Codealot

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Re: From no parts to decent stockpile, best approach?
« Reply #228 on: April 04, 2020, 04:05:30 am »
As for being worth you money, i think the simple answer here is could you buy all of this for less?   Most likely yes because it costs money to create the kits.
Not sure about that. It seems that some parts cost much more on DK or Mouser than in kits or on Ali, probably because of very high margin.
 

Online wizard69

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Re: From no parts to decent stockpile, best approach?
« Reply #229 on: April 05, 2020, 08:26:56 pm »
As for being worth you money, i think the simple answer here is could you buy all of this for less?   Most likely yes because it costs money to create the kits.
Not sure about that. It seems that some parts cost much more on DK or Mouser than in kits or on Ali, probably because of very high margin.

it isn't exactly "fair" to compare a kit from China with DigiKey's mainline products.   My point is you are still paying for kit box and the time it takes the vendor to assemble the kit.   that might not be a bad thing depending upon what you get exactly in the kit.    If you went to Ali express and purchased in bulk, which might make sense for resistors, you likely would have far more material for each dollar spent.   On the flip side you might end up with far more than you will ever use.

In any event I actually liked this kit because it does details exactly what you are getting and appears to avoid a lot of useless high value resistors.    I'm just not sue it makes sense for everybody, I'm still a fan of buying when you need something.
 

Online Gyro

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Re: From no parts to decent stockpile, best approach?
« Reply #230 on: April 05, 2020, 08:34:25 pm »
As for being worth you money, i think the simple answer here is could you buy all of this for less?   Most likely yes because it costs money to create the kits.
Not sure about that. It seems that some parts cost much more on DK or Mouser than in kits or on Ali, probably because of very high margin.

Probably because of genuine spec, in-tolerance components versus low quality or production line reject parts more like. You can't compare Ali parts with main line distributor ones.
« Last Edit: April 05, 2020, 08:41:35 pm by Gyro »
Chris

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Offline Codealot

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Re: From no parts to decent stockpile, best approach?
« Reply #231 on: April 06, 2020, 02:02:46 am »
Probably because of genuine spec, in-tolerance components versus low quality or production line reject parts more like. You can't compare Ali parts with main line distributor ones.
This may be the case for semiconductors and possibly even resistors, but no way it justifies their prices on cables and connectors.
 

Online DrG

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Re: From no parts to decent stockpile, best approach?
« Reply #232 on: April 12, 2020, 05:47:35 pm »
I think my approach has been a hybrid of already mentioned strategies. One that I find particularly relaxing sometimes is salvaging....

This cheapo DVD player that worked for a short time (a long time ago) before skipping around a lot...



becomes...



Not a huge haul, but some usable material...

25Q80 spi memory chip - I read the stored BIOS using a cheap programmer. Have not yet written it and tested it thoroughly.
ORPC-817 optocoupler (tested good).
3 x DC motors (all tested good).
s9014 GP npn (not shown but has good legs)
some switches - 1/2 dozen momentaries (all good) and a nice swivel switch (for lack of a better term).
usable padded feet and cables/sockets
a few other miscellaneous.

Much better this way than to leave it in the junk box until it is tossed.
I have not yet decided on the WTP-AD01 (the optical pickup). I might have a use for it some day, but will probably keep it as until I do some more reading.
« Last Edit: April 12, 2020, 06:03:14 pm by DrG »
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Offline eugenenine

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Re: From no parts to decent stockpile, best approach?
« Reply #233 on: April 12, 2020, 09:02:52 pm »
Leave the motors attached to the dvd mechanism unless you have a use for them at the moment.  There are projects around those complete mechanisms and its easier to leave them together then try to match up the right one later :)
 

Online DrG

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Re: From no parts to decent stockpile, best approach?
« Reply #234 on: April 12, 2020, 09:14:35 pm »
Leave the motors attached to the dvd mechanism unless you have a use for them at the moment.  There are projects around those complete mechanisms and its easier to leave them together then try to match up the right one later :)

Yeah, I thought about that, and you have a point, but I decided against it.
I looked for quite a bit for projects and didn't find anything that I could really get into seriously. Lots of clocks and lots of balloon busters / burners but those are for DVD R/W drives using the laser (and some pretty sketchy projects with regard to safety).

I did think about using the WTP-AD01 with a controller as a moving target (that motor can be reinstalled easily)....but I need a semi useless project like I need a ________.  :)

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Offline boffin

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Re: From no parts to decent stockpile, best approach?
« Reply #235 on: April 13, 2020, 04:11:44 pm »
I think my approach has been a hybrid of already mentioned strategies. One that I find particularly relaxing sometimes is salvaging....

This cheapo DVD player that worked for a short time (a long time ago) before skipping around a lot...

(Attachment Link)

becomes...

(Attachment Link)

Not a huge haul, but some usable material...

25Q80 spi memory chip - I read the stored BIOS using a cheap programmer. Have not yet written it and tested it thoroughly.
ORPC-817 optocoupler (tested good).
3 x DC motors (all tested good).
s9014 GP npn (not shown but has good legs)
some switches - 1/2 dozen momentaries (all good) and a nice swivel switch (for lack of a better term).
usable padded feet and cables/sockets
a few other miscellaneous.

Much better this way than to leave it in the junk box until it is tossed.
I have not yet decided on the WTP-AD01 (the optical pickup). I might have a use for it some day, but will probably keep it as until I do some more reading.




Is it really worth scrounging things like an 8050 transistor or 817 opto when those items are readily avail from a legit distributor (LCSC) for a few cents each (S8050 = 1.6c/ea, 817 2.9c/ea and that's in 10 lot).

Keeping an old board and if you don't have the component doing a quick scrounge makes sense, but pulling apart everything in advance?? (I admit I did this when I was a young teenager, but at that point parts were 10x the price). Back in 1979 a BC107 tranistor was 15p (UK), now I can buy them for 1/10th of that price and that's not adjusting for inflation.


 

Online DrG

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Re: From no parts to decent stockpile, best approach?
« Reply #236 on: April 13, 2020, 05:02:48 pm »
I think my approach has been a hybrid of already mentioned strategies. One that I find particularly relaxing sometimes is salvaging....
/-- snip --/




Is it really worth scrounging things like an 8050 transistor or 817 opto when those items are readily avail from a legit distributor (LCSC) for a few cents each (S8050 = 1.6c/ea, 817 2.9c/ea and that's in 10 lot).

Keeping an old board and if you don't have the component doing a quick scrounge makes sense, but pulling apart everything in advance?? (I admit I did this when I was a young teenager, but at that point parts were 10x the price). Back in 1979 a BC107 tranistor was 15p (UK), now I can buy them for 1/10th of that price and that's not adjusting for inflation.

I still favor this approach as a complement for parts accrual, BUT, with certain qualifications.

IOW you raise some good points. In fact, I looked up the motors and, sure enough, you can get them new for ~$1-2 US$. The memory bios chip was a surprising plus, but still probably only a buck or two. I already have a few of those IR sensors (1838 type) and so on. I have at least 25 opto's, none are 4-pin though (all older 6/8 pin - many salvaged and some high-gain darlington types that I bought). Optos are easy to test for suitability in my own projects. The switches probably will get used at some point. The cables and connectors *might* be useful - it is infuriating to need one and have little choice but to have to order it and wait.

There was plenty of stuff that I left alone (most of the power supply components).

Here are the general rules that I practice.

I will not give in to the compulsion to scavenge everything possible (I have to admit that if it was a small board, I might have at one time, removed, everything removable).

I no longer bother with scavenging the item, if it is fried or I have good reason to believe it is fried unless there are some specific things that I need AND can test out. An example is an old discarded radio that I scavenged for only the ferrite coil antenna and the telescoping antenna (both are in use right now).  When I opened it up, it was clear that at least one capacitor had leaked. I don't want inexpensive components that may be flaky, even to play with.

I don't (no longer bother with) scavenging the item for simple resistors and capacitors with very short leads. If that is all you can get, I understand and will not criticize.

I do scavenge nuts and bolts. I frequently search for small hardware like those and I can sort them in a bin as they are being removed (in contrast to dumping a large jar and trying to find the right ones).

Finally, I have to be in the right mood to scavenge and when I am, it is a relaxing activity. I have a hot air station and it is a little game (some kind of skill there) to remove items easily. I reduce the junk pile and add to the component pile.

That's my story and I am sticking to it  >:D
- Invest in science - it pays big dividends. -
 

Offline El Rubio

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Re: From no parts to decent stockpile, best approach?
« Reply #237 on: April 27, 2020, 12:54:15 pm »
Probably because of genuine spec, in-tolerance components versus low quality or production line reject parts more like. You can't compare Ali parts with main line distributor ones.
This may be the case for semiconductors and possibly even resistors, but no way it justifies their prices on cables and connectors.

I have to agree with Gyro, especially with cables and connectors. For example, Mini grabber clips for test leads. Got 10 pairs for a few bucks from China. Absolute garbage. I made 5 jumpers and destroyed one in normal use before I used it 10 times. I went to a local electronics supplier and got some Pomona mini grabbers. The were a few bucks each, but the quality is so much better. I wouldn’t be too concerned about resistors or ceramic caps from chinese discounters like Ali, but I wouldn’t buy semiconductors, or most any connectors- banana, rca, and especially RF connectors unless it is the last option.
Personally, it takes so long for something shipped from China to make it here that I usually forget why I ordered it to begin with. Plus, I’m kind of pissed at them for their actions during this pandemic.
 

Offline dbctronic

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Re: From no parts to decent stockpile, best approach?
« Reply #238 on: April 30, 2020, 06:12:48 pm »
I agree with El Rubio and Gyro about not buying certain parts. Connectors really can be just a complete waste of money at any price. RCA phono connectors that melt when you try ever so carefully to tack solder leads to them, shells that don't hold the connector body tightly...  no thanks.
And as for Chinese semiconductors, I don't buy 'em because I don't buy any semiconductors if I can't get decent datasheets for them. American made stuff almost invariably has good ol' JEDEC standard sheets. Chinese... anything from not available, to mostly Mandarin with a gloss of English, to strangely worded and organized, and obviously incomplete. I wouldn't have them for free. I'm not an engineer trying to hold down costs on things made by the 10,000s, just an amateur who can't stand to waste time making one-offs with junk that needs debugging and patching. And that's assuming you have the datasheets you need to do the debugging. Their '2N3904' may not be quite standard, and their datasheet may or may not tell you the differences...
And yes, they have misbehaved about their little unintended export, and its world changing consequences.
 

Offline DSE_Kid

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Re: From no parts to decent stockpile, best approach?
« Reply #239 on: May 06, 2020, 10:27:50 am »
Some great tips here! When I started as a hobbyist all my parts came from discarded electronics on the side of the road. These I work on vintage tube electronics and for the most part the only parts I'll buy new are electrolytics, everything else has a pretty decent shelf life.
 

Offline Electro Fan

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Re: From no parts to decent stockpile, best approach?
« Reply #240 on: May 06, 2020, 06:26:26 pm »
I’ve watched this thread develop.  Some good ideas and some humor in here.

I’m not sure if my idea belongs here or in the TEA thread but I’ve come to the conclusion that for most electronics enthusiasts it’s only a matter of time until your parts strategy will be constrained by either your budget or space and by that time you will either have implemented a storage and inventory management system that works for you, or you will spend some time trying to figure out how to better organize your your parts, bench, and lab. Along the way your significant other and friends might wonder how you work and live in there, and they will be impressed if/when you figure it out.   :)
 

Offline IJL05

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Offline dbctronic

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Re: From no parts to decent stockpile, best approach?
« Reply #242 on: May 15, 2020, 05:00:03 pm »
DSE_Kid is right. Old electrolytics are garbage. And just quickly testing them doesn't help much - an old tube radio that's been sitting around for decades has a distressing tendency to work for a few hours, then go south. The electrolytics grow an insulating layer that soon fails in use. If you buy old tube equipment, best idea is to just blanket replace 'em all first thing.
 

Online tunk

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Re: From no parts to decent stockpile, best approach?
« Reply #243 on: May 15, 2020, 05:08:11 pm »
GreatScott recently posted this video:
 

Offline JLCPCB Official

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Re: From no parts to decent stockpile, best approach?
« Reply #244 on: June 09, 2020, 05:07:37 am »
Hello ;

Cool kit as long as you keep them well arranged, specially the small components need to be all the time sorted, usually perform a sorting task for small stocks like once per month will help you keeping all you workspace organized and this way it will not be a "wasting money"  ;)
 

Offline VictoriaMcLean

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Re: From no parts to decent stockpile, best approach?
« Reply #245 on: June 19, 2020, 07:35:56 pm »
Thanks for sharing.
 


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