digital circuits

Hello all, I just want to share my electronic projects with the world. This is the start of my journey. I learned electronics in high school, but this is the first time in 14 years doing this. I built an arduino clone the Diavolino by Evil Mad Scientist and then I built an arduino from scratch on my breadboard since the kit was too easy. Then using a voltage sensor and i2c screen I made a voltage meter. I will continue to share my progress and would love to see what other people are building.

Nice to see someone do electronics around here. Don't miss the fun to be had with LTspice, especially when wanting to try out an idea or to flesh out (part of) a circuit before building it. I've gotten into FPGA's lately "Tang Nano 1k" is a real cheap and easy way to get started. You'd think the made-in-china IDE is like kicking dead whales down the beach, but so far it hasn't crashed or anything for me. Not many bells-and-whistles but thats good to start out. Picrel is a direct conversion reciever, uses "bus switches" as a mixer, to be more precise a sampler really. "Tayloe mixer" is what the cool kids call it. The "magnitude converter" means it detects AM. It even somewhat worked - good enough for soykaf on a breadboard at least..

It's good to see other lainons working on electronics projects! A while ago I made a small RGB strip driver board for an esp8266 on protoboard. I used it to set up a time-controlled light above my bed to wake me up along with my alarm. Turns out having a blinding white light in your face is really effective at forcing you awake. The circuit was pretty simple, just 3 mosfets + 3 mosfet driver chips, and header slots to hold the esp board. It was a fun exercise learning to solder on protoboard properly.

>>8636 Sounds good. One thing most beginners in lighting overlook is that RGB LED's make really poor quality white light (inefficiently). To put it plainly, objects can only reflect the colors your light source provides. If your light source only provides one shade of red, everything red will look the same. This is reflected in the "color rendering index" CRI of a lightsource. A CRI of 70 if for streetlights, 80 for general living areas and 90+ is what I'd recommend for kitchen and bathroom. Please note that this is a totally different metric than the "temperature" of a lightsource, which (oversimplified) indicates the ratio of red to blue. For DIY lighting applications very well suited LED strips exist with 2 types of white LED's, a very cold and a very warm type, called CCT for "changeable color temperature". With these you get a decent CRI, high efficiency and can change the colour temperature. Such a lamp can simulate not only the dimming of the sunrise, but also the colour change. Setting it more blue in the morning helps to wake up and to more warm in the evening assists the body to prepare for sleep.

>>8639 Yes, but remember that we can only see 3 wavelengths, so if it fit our receptors, it is virtually the same as a real white light.

>>8644 Might just be the effect stems from the mismatch between the specific wavelengths the eye percieves and what the RGB LED strip emits - an interesting observation - but reality is that any readily obtainable RGB strip will produce a bad color rendering at low energy efficiency, compared to a strip with "white" led's.

>>8633 Nice, I will need to get into FPGA's soon. Right now I am tinkering with simple circuits, but I could use some assorted components on hand so that I can actually build what I want to build. >>8636 I want to do some work with LED's. On one hand I want to build some decent grow lights and on the other I want to build my own DIYHue lights which are novel colored or white lights for IoT which can be pretty pricey even if I bought the off brand smart lights. I want to do my entire house, pool and surrounding property. Not only that, but I want various sensors to detect intrusion and aerial as-well. Not totally out of paranoia for drones, but partially yes to monitor for drones, but also to watch for birds of prey to protect my livestock and other things including air traffic and satellites which i know can be done with RTL-SDR. My goals are growing and variable overall, but they will all play hand in hand in a full scale diy lifestyle and hopefully off grid whether in a stationary home or in a van/boat. I will practice my electronics and circuit building by making the things that I will be using in my hobbies that I hope to turn into lifestyles and income cash money. I want to build some amplifiers and audio circuits, am/fm radio along with uhf and other marine communication and navigation devices. I want to make Iot devices and garden controllers for my indoor and outdoor plants. I want to learn to sew so I can reupholster my car, but I want to embroider with EL wire if EL wire can be used in embroidery. There are a bunch of car mods I could do. There are designs to build entire computers from scratch along with building your own operating system. Oh and with all the guides on making my own 6502, gameboy, nes and many other emulators and physical clones I will be learning much quickly. Anyway I could go on and on, but basically I have a 5 year plan that I am on the fast track for so I am gunning for 3 years and to use the other 2 for more advanced skills. I am working on circuit design and mcu programming, linux administration, learning a foreign language and to have a pretty decent portfolio of all my various projects. I may seem to be jumping into some big projects and I know I am. But I am not a novice, nor an expert in these things. I learned a bit in high school, but also didn't pay attention and thus didn't get it when I did try. But I have learned quite a bit by jumping into linux over the years. Building my pc and server, doing the networking and hosting vms and containers. And lots and lots of troubleshooting. However I learned from project to project and that hindered my learning compared to if I learned by the books, which honestly bores me. The reason it hindered me even though my experience is strong it is lacking. I am not great at bash scripting for example and I hardly use aliases. Both very essential and basic skills that I just neglected even though I learned a lot of much more advanced skills. I will make sure to study the principles of electronics and understand the parts of the circuits I am building so that I can truly apply them and design my own circuits.

>>8644 But this can't be true - structural coloration which rely on interference won't look the same as they would in full-spectrum light. Not a common issue, but I bet a lot of fabric will appear subtly different in halogens vs LEDs.

>>8644 >> can only see 3 wavelengths That's not true at all. We have three types of color sensing cell on out retinas (4 if you count the rods, but they're not involved in color perception), and each type responds to a range of wavelengths, with a certain "intencity" for each wavelength. They kind of roughly correspond to blue, red and green, but not really (there's overlap). So you can see infinitely many wavelengths, and each wavelength will cause a specific cone response. Natural light is a mixture of a bunch of wavelengths, because that's what the Sun puts out. The reason RGB lights make soykafty white light is because they will render color incorrectly, as >>8639 pointed out. I would add that CRI is a flawed metric and if you want lights that will actually reproduce colors correctly, you'll need to look at their spectral distribution curves and compare them to a standard source such as D50 (basically daylight at 5000K) or D65.

I feel overwhelmed by electronics. I took a class in electronics in high school but never learned anything but reading schematics and how to solder. How do you even learn how to understand how circuits actually work so you can fix problems in them and design your own? It feels like it might be way over my head.

>>8652 You don't really need to learn a whole lot beyond kirchoff's laws and the characteristics of basic components. Resistors reduce current flow, diodes only let current flow one way, capacitors charge and discharge, and so on. After that, it's just a matter of using said properties and combining components into a circuit to get the result you want. Here's a really good applet with a lot of examples and a neat visual representation of current flow, which I feel really helps. https://falstad.com/circuit/circuitjs.html

>>8652 Yeah it isn't difficult once you watch some videos and get started. You will need some tools and basic components, though there's software that you can build circuits and test them in now too. I learned a bit in school, but I'm mostly learning now by just doing it and I graduated 14 years ago. It's advanced Legos. Learn to read a schematic if you don't already know and start building. Then learn as you go by learning what each part of the circuit does and doing calculations/ take readings. Once you get the hang of basic circuits pick a project you want to try like building an am/fm radio. Maybe get a project kit.

>>8654 >>8710 I was watching Physics Videos by Eugene Khutoryansky on YouTube which seems to have good explanations on electronic parts and circuits but as soon as it comes to equations my mind just blanks out. I'm guessing trying to memorize equations without first actually using them is wrong approach? Problem with project kits for me is everything is so laid out there is little motivation to figure out how it actually works because as long as you can read a schematic you don't have to know.

I am getting into logic ICs right now. I think a 7 segment digital dice was the first project I did with it. Now I'm kinda stuck...

>>8654 >you don't need to learn a lot of stuff UNTIL you mess with transistors and/or noise generated by your circuits that mess with working of circuitry. But yea, even with the basic stuff you mentioned people can build own homebrew computers. Digital stuff seems to be easier than analog stuff nowadays.

>>8971 Even on digital stuff, signal integrity is important. But you can just run it slower (usually), as a bandaid. If you want it real fast, it's basically RF territory. If you want an overview on the subjects of shielding, grounding decoupling, etc. "Electromagnetic Compatibility Engineering" by Henry Ott is a good starting point. "The Amp Hour" podcast #165 is an interview with the guy, well worth the listen if you're interested in the subject. The point in analog is you have to deal with noise as one of the limits to your dynamic range. Grounding, shielding and decoupling only help there to an extent, the "Keithley Low Level Measurements Handbook " might be of interest, as it points towards some of the other fundamental limitations.

>>8727 > but as soon as it comes to equations my mind just blanks out To understand electronic circuits you literally need only 3 equations: The Ohm's law, and 2 Kirchhoff's laws. Now... to understand how the individual components work, that's a different story. >>8968 > 7 segment Boring. Get 14 segment displays. Much cooler.

>>8984 On equations, I agree - for DC. For AC you also have to be able to calculate the equivalent impedance at the corresponding frequency, at least. That'll get you a few steps in, it's not bad. But then, there will be a phase shift and now your're in trouble because you need imaginary numbers as well...

All cool, OP. I always wanted to tweak with electronics. That might motivate me to try it.

>>8727 >>8727 The reality is, mostly in electronics (and especially for home players) "in the ballpark" is close enough. That's why there are very simplified versions of the equations that are good enough 99% of the time. Once calculated a few times, you'll get a feeling for which values of R or C might be a good starting point. Of course, universitys love to explain everything up from mud and tell you in the end "oh yeah, the three pages of derivation were just to educate you, use this shorthand formula from now on". Thing is, derivations are one way of teaching in which way things correspond to each other. In which way the effects and causes are meshed. But these things can be teached and understood in other ways, so don't despair! Of course, a little bit of math goes a long way, but 99.9% of the EE's in industry will tell you "I never used differential equations after university". The other things is, we have incredible simulation tools now that hide these complex equations from us and allow interaction on another level. LTSpice beeing the tip of the iceberg so to speak...

>>8727 Don't try to memorize equations. Make sure you have a cheat sheet and a scientific calculator (don't use phones, they're distracting). Learn how to operate the calculator, after all you gotta know how to use the tools you have in hand. Look up some questions that include whatever equation you want to memorize then solve them. At some point you will have memorized the equations. I wouldn't worry about memorizing information that is easily available in almost any electronics book. Even professionals consult books.

>>8727 Here are two books I recommend

Where to find professionals to quote a project? How much does this process usually cost? I want a Brain Machine like the Procyon Mindplace, or Kasina Mindplace but in addition to being very expensive it is very difficult for an electronic device to pass through our customs without being taxed or stolen, my idea is to get it from a freelancer and compare prices, a freelancer could also declare the product as a gift to pass unscathed by the inspectors.