Imagine not understanding anything about furniture in your home beyond how to use it. You have no idea what wood really is, how hinges work, or how to swap shelves around. That's most peoples relationship with electronics. Buy stuff, hope it's a fit, use it until it breaks, throw it out. Then one day you set up a basic woodworking/painting area and do a little reading, and suddenly you can fix stuff around the house. Make that shelf fit. Fix that wobbly chair. Throw together a frame for that photo you could never find one for. That's what learning electronics is like. It demystifies and empowers.
When I was a kid (in the early 80s), I took more things apart than I perhaps should have. I feel a bit bad for having ruined what can now be considered antiques, but they weren't back then of course (nor was I >_<).
Usually this type of story ends with "...and that's what set me on the path to become a professional electrical engineer". However, I did not. Maybe I'm just not clever enough. Even so, as I grew up, my interest in how things work remained. I still remember how captivating the hobby tech catalogues were to me. Aside from the lack of information (80s...), components were expensive back then, so I never really owned much to experiment with.
A lie detector I made a long time ago. Only Stormtroopers are this precise. But it works. I think the transistors amplifies the measured skin conductivity. The trimpot sets the threshold for the LED to pop on. It's tempting to do some restoration, but I think I'll leave the artifact intact.
A few years ago, micro controller hardware suddenly seemed less intimidating, so I bought a off-brand Arduino UNO on Amazon and a small component kit.
An Arduino UNO by Sainsmart, featuring the ATmega328P-PU. It's actually getting ready to program a smaller micro controller - the ATtiny85.
I had a lot more fun with the UNO than with the more advanced Raspberry Pi, perhaps because the latter is unwieldy to fire up, whilst the UNO gets right down to business and you don't have to worry about frying it. Also, I guess the appeal for me is to just make random things - I don't really have a goal, and the RPi seems more goal oriented. It's a thing you buy and install linux on.
Unfortunately I soon discovered that the prices & shipping on Amazon, and certainly in local Swedish electronics stores, would make this hobby a very costly one.
So for a while I was stuck, not being able to afford a critical mass of components. When I discovered a forgotten $50 stash on an old PayPal account I finally decided to check out that sketchy eBay site. The prices I saw there baffled me! 100 thingies for one dollar, free shipping from... China? Too good to be true? I took a chance and spent my cache. A few weeks later a box full of goodies arrived, stuff which would have cost me ten times here! Since then a steady stream of parcels have made their way to me. "[X]Gift. From Mr. Yuan".
This discovery is partly why I made this page. I want to let people know how (relatively) affordable and fun electronics can be in 2016+. All the prices on this page are from eBay, China sellers. When it comes to components, (learning materials in my case) cheap is less of an issue than it is for tools. AliExpress prices are similar but they sometimes offer different kits/sets. Because shipping and handling costs are actually included the price and not really "free", it's often economical to get the larger packs if you feel there's a chance you will be using more than e.g. 10 thingies.
>>> 2018 note: The reason for the low shipping cost appears to be subsidisation by the Chinese government... some sort of strategy to capture foreign markets, probably. Import rules have changed in Sweden so now it's a bit trickier to buy direct from China (package delays and additional fees due to VAT processing). I believe DX has a stepping-stone warehouse inside the EU (Netherlands) which might be feasible workaround.
First "eBay gamble" order. Bags are about 1~3€ each, with 0.99 US dollar being common as a lower threshold set by sellers to make "free" shipping feasible. The goods seen on this page are not purchase recommendations, but perhaps inspiration. Because this was my first purchase, I made a few mistakes, like the massive diodes and the power transistors at bottom. The yellow/black buttons with red caps are made for use in custom cases (wobbly without that support) and I don't like them (very clacky).
Got excited when it worked, ordered some more stuff. LEDs, Voltage regulators, diodes, coloured test hooks (quite useful). etc.
Also, some Arcade stuff to go with my Retropie project (stalled).
ESD mat, oscilloscope kit, switches, Dupont stuff, Ceramic/Cement resistors, etc. The 0.1mm copper enamel wire might be useful for wiring SMD LEDs inside figures, but I didn't know that when I got it. I got it because it just seemed useful for something. When stuff is cheap you can take these sort of risks.
Some stuff I didn't really need (Edit: Or maybe I did...). Could get the USBtinyISP to work (Edit: but figured it out later). Haven't tried the STM32. The 1.5V+ to 5V step-up was handy though. I've used it with my decades-old solar panels and old batteries.
Bought a PLCC extractor when I really actually needed a DIP extractor. Got a laugh worth a few cents back though. Colored headers are useful. I go through a lot. DIY audio amp kit was quite satisfying to build as it has a fun mix of different components.
I really like older tech that's more... physical, such as VU meters. This one is 5V and can be used to test batteries I suppose. I made a bicycle speed meter of it, using a hall effect sensor and neodymium magnets. Can't quite explain why I bought a whole bunch of DE-9 connectors. Hoarding instinct, perhaps.
I had to sell state secrets to get a hold of this Zikret Tcheknologjy...
305 meters of 30AWG Wire Wrapping Wire! Good for wiring on circuitboards (but I'd rather have more colours than this monotone excess). Handy breadboard power supply (3.3 and 5V), Mi Ni dc variable power supply (handy, but eats battery even when off), 5.5/2.1 jacks, ATmega328P-PU in levered ZIF socket (for ease of swapping). And a golden thingamabob.
Yule. $50 contingency Android phone (an unfortunate necessity these days... a hardware miracle leveraged against you). ICs:ULN2003A,L293D (both motor drivers), SN76489A (used as sound chip in e.g. the SMS). Two component testers (Tried the yellow one, very handy!). Misc. project boxes. Potentiometers 10K, 5K, and rotary encoders. Mini vice, Helping... deep sea spider (too springy, turns out). More 5V step ups, cheap red laser emitters, temperature IR gun thingy with terrible sights (but better than nothing when needing to check temps). Female barrel jacks for panel mounting, Panasonic (mouse) switches. The syringe has liquid solder glue for PCB repair.
Shift registers, soldering sponge, spacers/board feet/pods (M3). Headers with long pins, volume wheels, A03 caps which were the wrong size, tiny stepper motors (???), Ferrite EMI thingamabobs to clamp around coords, R/C boards, etc.
A dremmel is apparently useful for cutting and polishing. Also got some finger cots that are handy (fingy?) when you don't want to wear full gloves, or if you have a finger cut and are doing the dishes.
I bought some SMD LEDs and other components to experiment with. I laid down a track with the syringe containing conductive silver glue (not conductive until dry / a day?). Somewhat durable (can be scraped off with a knife and some pressure) but probably best for lighter SMD work and track repair that won't be handled. Would be handy if it wasn't for the short shelf life (kept in fridge). If soldering SMD using an iron, use the green double-sided boards, not the brown single side ones.
Wire/Cable stripper (works okay on medium gauge and up, ribbon cable, but will chomp lone thin wires). Found some multicoloured wire wrapping wire good for doing backsides of prototype boards (will snap off if wiggled a lot). 2-core cable that I use for 5V power (cleans up some of the wire mess). The ATmega board case I bought doesn't fit the clone board. Bought the wrong diameter drill bit for my arcade project (big button holes). SMD vacuum pickup tool (not really that useful, probably best for lifting e.g. SSOP ICs).
More importantly, a 936 clone soldering station which I had to change the plug on, but it's a worthwhile upgrade from a cheap plug->iron iron. Also, it's easy to find tips for this model. I do prefer the default, pointy-cone tip as it retains heat well and isn't angle sensitive during contact (like the flat-head tips some people have recommend). Could not go back to the simpler irons now. Be careful when buying cheap AC devices as some can be dangerous. Take a look inside and don't leave running/plugged in unattended.
(By the way, SMD caps can be taken apart and used as through hole components.)
Flux pen... A tube with.. heatsink plaster? Perhaps I intended to attach the small aluminium heatsinks to MOSFETs? Solar panel which gives 7V in the summer sun. Buttons with LEDs inside! Vibration motors for my cat-purrer. I discovered that it's easy to have too few breadboards. More storage boxes are needed, even after buying these. 16DIP sockets, too few, bought 50 more later, as these are commonly needed. Some yellow LEDs finally. Gives a nice yellow-orange light rather than yellow-green.
Getting 2*1000 1/6W (or 1/8W?) resistors (not 6W...) into the tray was not an easy task. Shift registers in nice and heavy cold-to-the-touch packages. Ah! So I did buy SMD resistors. By now I have so much stuff I forget what's in my inventory. I need to make a list.
Bought 1000 googly eyes. How's this electronics related? Well...
Eeh? The problem is not too much stuff, but too little space in EE corner.
More displays with a little driver chip. My Intous 4 cable was broken so I made a new. Supposedly ferrite cores prevent... interference... something. Look, they're probably important to put on some cables, because I keep seeing them.
A PCB holder. Wish it had an arm/pad to hold components in place but those cost more. Here's my Amiga 500 extra-memory being patched up. This appears to be more sturdy than a "helping hand".
I bought this neat thru-hole UNO board from Thailand (ebay seller tinyelec). It arrived surprisingly fast, but cost a little more, about 7-8€ iirc. which is still low for a custom product like this. Components are soldered on straight with no flux gunk. Interesting use of a bridge rectifier if it does what I think (sorts out barrel jack input polarity at a small cost). The jumper is likely for selecting power source. Guessing chicken behind USB jack is a fuse or ESD protection thing.
So far, linux has been the best for Arduino stuff as it seemingly supports both FTDI and CH340G chips out of the box. My linux laptop gives some creative mobility. Like with breadboards, it's convenient to have many boards, not having to dismantle ongoing projects. But, I really don't like the header layout of the UNO board as it prevents making simple "shields" from regular breadboards. However, the smaller boards like Nano and Pro Mini are a bit fiddly to handle and took some time for me to figure out (see page about board interfacing). I'll have to make my own I guess (see Arnetronics section).
Another shipment, including: A handy ruler with pad reference on both sides. Kapton tape (heat resistant, can be used to isolate or maybe shield/mask stuff when using a heat gun). Fan that fits my RPi3 (those can run a bit hot). Cheapest UNO board (with CH340G). Buncha DIY (soldering practice/study) kits for a rainy day.
More stuff in the mailbox. Tesla coil kit (already built, actually a decent speaker, but it gets very hot quickly). Making a PC-engine controller from parts, but have now ordered a proper wired Mini Din 8 cable to use instead of these plugs. Schematic a WIP and theoretical. Will cut tracks to USB IC glob on joypad.
Larger 9x15 prototyping boards (tempted to build a computer of some sort when I get good enough). Arduino Due (likely a copy). Nokia 5110 color TFT variant (I see a 662K 3.3V reg on the back, and bypass pads). ATtiny2313A-SU (SOP-20) for projects where the ATtiny85 has too few legs. Female headers are a bit time consuming to cut, and 2-wide one double so, so I got some of smaller sizes. Ran out of male 2.54mm/0.1" dupont pins (used in breadboards and Arduino headers) (female leads are good for putting on things which provide power, as the leads can't accidentally touch & short, but I don't use them as much). 1N5817 diodes (low voltage drop).
Soldering, every time: Plan: Great 2-birds-1-stone layout. Execution: Dumb-mistake, 104 stones. Mystery wound on thumb. This is just a little LED test board (card really, with an edge-connector), driven by a ripple counter. And what's that? An Amiga! Oh, Amica... it's just an ESP8266 WiFi thing. It's a bit more beefy than the typical Arduino thingamabob, but nowhere near a SBC. The LEDs on the "KYX-B10BBGYR" bar needs separate resistor values for the LED intensities to match. I might recommend (for indoor & 5V): Red:2K2 Yellow:560 Green:10K Blue:750.
Nylon M3 and brass spacers, displays, another loose ATmega328P-PU (I should try the one with built in USB some time though), ESP8266 board with Arduino headers, USB doctor, Various SMD buttons (I hoped to use the flat gold ones with my 6mm rubber feet (like I did on my PocketChip) but these were too small for it to work). Radial inductor set, F3 LED holders, round DIP-28 sockets (quite tricky to fit the 328 IC into these actually). 2N2222 and light sensor in UFO packaging, and a few bridge rectifiers.
Another lot. Cable for PCE project. Breadboard-friendly microswitches. More MOSFETs to fry. 20MHz clocks, SD card thingies, some with audio features. Might use the larger to replace/bypass that plastic junk on my RPi 1. Stereo Amp (so-so). Seems like a lot of variables to consider when designing a speaker system. Amplifier IC, shielding, PSU, cap quality, speaker, box/enclosure acoustics...
Went and got the AN8008 like some sheep after seeing that eevblog. But I did really need a second, smaller meter to compliment my Voltcraft VC270. Loud beep. Alarming beep if one forgets it on. The screw stuff on some leads tends to unscrew.
These came in the mail and are so nice. Cold to the touch and a bit heavy, so maybe ceramic packages. NOS from a Finnish seller. They quite precise (doesn't make sense to put cheaper resistors in expensive packages I guess). Ah, MDP1601 = 16 pins, 1% tolerance. 1/8 Watt according to datasheet. Gonna be handy for pullup/down.
More components and kits in the mail. Leonardo, very likely with fake branding. Its MCU (ATmega32U4) has onboard USB, removing the need for a serial helper chip, simplifying the design. It works under both Linux and MacOS so apparently no driver issues. 74 and 40 series ICs. SOP/SSOP breakout boards. 0.33uF caps (preferred in simple L78xx regulator setups). Audio sockets. These fit in breadboards but the flat pins are too wide for green perfboards. Assorted board drills. A Clock/Voltmeter/Thermometer which keeps time poorly and flickers visibly. Negative supply voltage thingy. Mp3 player board, I think. Some logic level converters. A little amp kit, and other kits. SMD resistors 1K and 10K. SMD RGB LEDs, and also an Arduino shield with 5050 addressable LEDs (tested it with the Leonardo).
5050 LED (5x5mm). There's a little IC inside managing serial communication.
Soldering 0.05" pitch was frustratingly difficult until I figured out the technique. Flux pen on pads/legs. GreenStuff IC down. A small flat tip on iron, thin solder on end of pad, then slide/push up towards the legs. Had room left for a small RGB LED on this board too. The ATtiny2313A-SU just barely fits.
I've seen people solder one pad and push IC into that to position it, but the IC skids around a bit. GS keeps it in place (though it gets viscous if heated.) Some people add tons of flux and tons of solder then suck solder up after with wick, but this seems dangerous & messy.
I found some TF -> SD adapters which are very rigid... sort of works with the RPi1 and its problematic socket. However, there's no indent for the write protect tab/switch, and this seems to create trouble in RiscOS, which was all I could fit on my 2GB test card. Unsure of Raspbian checks the leaf switches in the card holder. Also, note that the adapter had a metal door. One can't simply push in the card, I discovered.
Wow! These vacuum tubes are as tall as a man! Oh. It's just a miniature lol I thought it was a real person, it's so realistic. Driving tubes is a pain. I got em in a cheap amp kit and will probably just use them more for tube-punk art reference.
Great practical idea: All ICs should have an onboard status RGB LED. Certainly looks very HAL/Reaverbot, especially if running at minimum power so the internal details come out. Red looks very ember. Blue looks... Atlantian.
RGB LEDs actually have three individual LEDs inside but they're hard to see unless dimmed close to their respective limits. Top right is common anode/power, with teeny-tiny wires going out.
More 74 and 40 series ICs + DIP-14 sockets. I ordered blue boards but got green. Also, only got one 2.7V super-cap, but had ordered two (for a 5.4V total). Oh well. Precision trimpot with a cool knob... maybe for my cat purrer. Resistor networks (10K, shared common).
A bit about the (heat-)conductive silicone pad / tape:
I did a quick test using this sticky pad/tape and a small aluminium heatsink applied to a voltage regulator. The heatsink got warm, so it seems like the tape does transfer heat. At about 7-10 degrees over room temperature, I got a 2-3 degree difference between the two voltage regulators in the test, front and back (heatsink on back).
The pad quite mushy and actually squishes out under the heatsink so it's possible the cut pads need to be slightly smaller than the heatsink. It does not seem to cure, so the heatsink can wiggle a bit. I also have heatsink plaster but it's probably destructive (not so good to use on vintage computers). ...Oy! Oy! I just noticed that the blue heatsinks I got already had 3M tape on them, so I'm not sure why I got this silicone stuff... (U°A°) Oh, it appears to not stick things on very firmly, but it might not be an issue for things not often bumped.
Super-Capacitors: 0.33 Farads and a handy 5.5 Volt. These charge quite quickly, though slower towards the destination voltage so it's hard to time. I got 3.5V after seconds, and maybe 5V after a minute or three (note: never charge higher than voltage rating). I charge using my bench PSU with a 0.15A limit to be safe, also being very careful with polarity.
The quick 3.5V charge could drive a red LED + 10K Ohm for over half an hour (a 0.3mA load?). From 5V, it went down to 3.5V in 45 minutes and 1.6V in 4hrs. Another 5V test ran my ATtiny85 board for 8 minutes, but it had some green LEDs blinkies. In storage 3V remains after 24 hours.
Getting longer uptimes with 5 in parallel. Here I'm powering a common anode RGB LED DIP thingy I made. I just put a 10K resistor on each channel, which might not be correct as the voltage drop is different for each colour. Only noticeable when the V falls low though.