DIY software development and/or electronics?

What skills to learn, what tools to get
leecalvin
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Re: DIY software development and/or electronics?

Post by leecalvin »

Not quiet sure I understand the question posed.

How about contributing to some open source software? The question seems to be focused only on personal usefulness, I'm sure there's stuff out there that people already find useful that you could perhaps help improve on.

You could also do a lot of stuff with a personal server if you were so inclined, you wouldn't be writing code from scratch but your understanding of code would help you in understanding some of the nitty gritty details in setting such a thing up.

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mcs2269
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Re: DIY software development and/or electronics?

Post by mcs2269 »

I was looking for something like Plaid, so I'm glad to have found this thread. Thank you people.

zocab
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Re: DIY software development and/or electronics?

Post by zocab »

Some hobbyist and later open source programming is what eventually lead to my actual "career". My degree is vaguely related but not actually useful for the work I do.

Programmable blinds sound like a great idea, currently I just use a commercial wakeup "lamp" instead (bought before I knew what I was doing with my money) - but during the summer months it gets light early enough that automatic blinds would be nice. However: my blinds aren't electric, and they're actually quite noisy (not so nice for the neighbours upstairs), so it ain't going to happen. I also tend to wake up naturally before any lights go on, so the usefulness is debatable anyway.

But ultimately, after programming all day for money my brain doesn't want to program during my free time. I expect this to change when I retire. I could probably do some more development on the side for side income if I ever get bored. There are also some nice community aspects to a lot of open source projects, at least nice for introverts like me. And if you have the right contacts you can get paid to work precisely on those open source projects freelance (that's what lead to full-time software in the first place).

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Stahlmann
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Re: DIY software development and/or electronics?

Post by Stahlmann »

zocab wrote:
Mon Aug 12, 2019 1:31 pm
Some hobbyist and later open source programming is what eventually lead to my actual "career". My degree is vaguely related but not actually useful for the work I do.
plz share success story

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Sclass
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Re: DIY software development and/or electronics?

Post by Sclass »

I designed some circuitry this week. Its for an adaptive hysteresis filter to capture zero crossings out of a noisy signal with widely varying input amplitude. Since it is a prototype I decided to mill it out on my CNC machine using isolation routing. This way I can see how it works before I commit to a PCB.

Here is the outcome of the week's work.

Milling. First one I messed up by going to cheap on the outline router. I wanted to save my carbide and used a high speed steel dremel bit which was a big mistake. The second one was cut with a 4 flute carbide endmill and the cut quality is excellent.

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The finished board. Isolation tracks are clean. Cut with a v-groove carbide cutter from China. Grid is 1cm.

Superb rout quality using carbide.

This is in mostly 805 component sizes. The chips are SOIC 8 and SOT23-5.

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Next step is to solder the chips down and test.

Some takeaways learned today.

Use carbide. China prices for carbide circuit board bits (1/8" shank) have really gone up in the last few years. They used to be almost free. Now They cost a dollar apiece. For reference they used to be $0.35 each. Has anyone noticed this with those China epackets? Big increases across the board on electronics. It's still cheap but the percentage increase is dramatic since pre-covid.

If the circuit performance is good I'm going to try one of those Chinese PCB houses that let you upload online and ship the boards to the US. The kind the last administration was trying to tax. These are still cheap compared to domestic fabs. Even with international shipping it's roughly 1/10 the cost per pcb.

I used this online G-code simulator extensively to validate my engraving and drilling code. I used to have to pay for these tools. This online one is excellent. You can literally teach yourself CNC using this website and never get up from your PC. Great for playing with CADCAM without actually having a shop.

https://ncviewer.com/

Inexpensive PCB fabrication (there are a ton of these places so this may not be the cheapest but it is dirt cheap for small runs).

https://www.pcbway.com/
Last edited by Sclass on Thu Mar 04, 2021 7:38 am, edited 3 times in total.

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Sclass
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Re: DIY software development and/or electronics?

Post by Sclass »

assembly. Testing.

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ducknald_don
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Re: DIY software development and/or electronics?

Post by ducknald_don »

Neat. My son does a lot of surface mount work. I don't know how he manages it, I can barely see some of the components he is soldering.

7Wannabe5
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Re: DIY software development and/or electronics?

Post by 7Wannabe5 »

Very cool.

SavingWithBabies
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Re: DIY software development and/or electronics?

Post by SavingWithBabies »

Well Plaid was linked for financial account data but if you're interested in getting financial information like stock prices, this looks interesting:

https://financialmodelingprep.com/developer

Free for personal use up to 250 requests/day with data limited to "5 years and 5 quarters". Might be a bit too low on requests/days -- not really sure. I haven't dug into it yet but curious if anyone else has found free or nearly free resources for this kind of information.

@Sclass That is really cool. My dad made circuit boards at home with the toxic process. So far, I've only used preassembled bits and pieces and bodged things together (resorting to a piece of cardboard in some cases). It is amazing how inexpensive custom PCBs are today.

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Sclass
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Re: DIY software development and/or electronics?

Post by Sclass »

I simulated a circuit on http://www.partsim.com.

It’s a free online SPICE simulator. A lot easier than breadboarding and measuring with a meter and scope. I’ve tinkered with spice in its various forms over the last thirty years. This is basically the same thing but it’s a lot easier to use. Drag and drop. You can learn all the basics of resistors, capacitors, inductors, various diodes, various transistors and other electronics devices. You don’t have to search for the correct value of resistors or burn yourself with a soldering iron to try designs out.

On another interesting side point I’ve been working on a test fixture to test out finished assemblies of the board shown above. Traditionally one could have build a lab setup using a signal generator, power and an oscilloscope to check output. Or, a PC based data acquisition card with software like Labview has become popular in recent years. Personally I like building custom fixtures controlled via usb on a pc for acquisition and record keeping.

Yesterday I considered using a significantly simpler, lazier and cheaper method that may be of interest to people here. There is a whole line of super cheap electronic lab test equipment on ebay that is appropriate for testing simple circuits or training students. I found $10 function generators and $16 oscilloscopes. I’m going to get a few of these and mount them in a 19” rack and create my own “instrument” that will feed in wave forms into the device under test and display outputs. I need two scope channels but at $16 a single channel scope I’ll just buy two.

This stuff. Maybe a resource for those who want to learn on a budget? With a $2 breadboard, a $5 Harbor Freight voltmeter, some jumper wire and $5 of components you can start trying circuits. There’s function generators too. I think you can set up a really cheap electronics lab bench for less than $30. Try circuits found online. Add an Arduino and you have some significant capability. I would have killed for this stuff in the 1980s when I was a penniless kid.

You really can get all the intellectual content that a university level lab has without all the expensive test tools.

This scope lists for $16 buy it now.
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I found this waveform generator in Kit form for $10. Bonus is you learn how to solder and assemble it using YouTube.
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sky
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Re: DIY software development and/or electronics?

Post by sky »

I need an oscilliscope and waveform generator. Any recommendations?

I have been working without those tools for a long time, but it is difficult to troubleshoot problems, or even know if things are working correctly without them.

plantingtheseed
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Re: DIY software development and/or electronics?

Post by plantingtheseed »

https://www.eevblog.com/forum/beginners ... ss-(long)/

People swear by Tektronix but they're $$$.

I think Sclass' function generator / oscilloscope combo would get one through the important basics for a song! :shock:

SavingWithBabies
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Re: DIY software development and/or electronics?

Post by SavingWithBabies »

@Sclass Have you thought about 3d printing a test adapter with pogo pins? Probably totally unnecessary but if you have a test a bunch of them and want to tinker anyway, might be fun.

To explain what I mean to others, pogo pins are a spring loaded pin mean to press down on a metal contact to complete a circuit. An example of them in a consumer product is the $25 Bluetooth earbuds I purchased from China. They use two pogo pins for each earbud within their charging case (which also has a battery so it can charge on the go, amazing what you can get for $25 these days) to complete the charging circuit in order to recharge the tiny batteries in the earbuds. If you design your circuit board for it or it happens to work for it, you can put specific contact areas for pings in a jig or holder to press down upon the circuit board and quickly perform diagnostics on the board (or even flash firmware). I'm geeking out over them but I haven't actually used them for anything and it's super basic but still really cool to me!

Oh, and the ear buds I bought are Edifier X3. They work great once I tweaked my wifi settings to avoid interference with bluetooth (before that, had random static issues on bluetooth with them but not other headphones). I was surprised that even the mic on them works fairly well. The touch controls are not that great as far as I can tell but that is not important to me.

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Sclass
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Re: DIY software development and/or electronics?

Post by Sclass »

SavingWithBabies wrote:
Tue Feb 16, 2021 4:37 pm
@Sclass Have you thought about 3d printing a test adapter with pogo pins? Probably totally unnecessary but if you have a test a bunch of them and want to tinker anyway, might be fun.
Funny you ask. I’ve been working on one right now. I’ve 3D printed the base that uses pogo pins for power, ground, signals. I’m working on a top clamp that will bring in my EEPROM programming signals to my cpu on five smaller pins. I’d print the toggle clamp since they seem to have some really nice designs on thingiverse but I already have a Destaco clamp left over from a prior project. I’ll post up photos once it’s all together. For this board it necessary to plan for volume testing.

I used to make test beds with my CNC machine. The 3D printer is just screaming to be used as a PCB fixture making machine. If I still worked in the biz I’d put one on my desk next to my pc. Test fixturing is a scary and expensive afterthought in board design. Nobody worries about it till the end of a project but it needs to be done if you plan to make anything in volume. It’s one of those custodial jobs that management forgets till nobody is there to do it. I bet cheap 3D printers have revolutionized this process. You can imagine how small changes in a board revision mean reworking all the bed of nails testers. It’s a scramble at the end of a up rev on a production part. 3D printers must be changing that into a breeze.

The design I’m working on is so dense I didn’t have room to add a plug to flash the microcontroller. My plan was to use a clip on probe for SOIC8 but I decided it would be so much cooler to make a pogo pin prober attached to a Destaco clamp.

Oscilloscopes are getting really cheap now. If you’re just starting out I’d try the junk on eBay. The worst that will happen is you’ll find it isn’t good enough for your needs and you can move on without a huge loss. I’ll end up with the signal generator and scope combo I showed above. Although it’s just a glorified strip chart recorder you’re basically flying blind without a basic unit.

If I needed one right now I’d probably get the mixed signal one from Rigol. It is sooooo cheap for all the features. What you buy depends on what you are doing. RF engineers need high speed ($$$) units. I use a mixed signal unit for digital and analog sync. A guy doing industrial work may need an armored hand held battery operated unit like some of the glorified DVMs out there. For a beginner trying to see the unseen get the eBay junk.

One reason electronics is hard for people is you cannot see and intuit electronic systems naturally. How many people have said “I have a good mind for mechanicals but I don’t grasp electronics”?We’ve evolved to see a big rock rolling down a hill squashing our friend getting chased by a wooly mammoth. Not electrons flowing this way and that hindered by counterintuitive impedances. A meter and scope are your eyes. Hit the books (YouTube) and learn the theoretical outcomes (physics). Then start observing with your new eyes and you’ll see the rock rolling down the hill.

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Sclass
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Re: DIY software development and/or electronics?

Post by Sclass »

Ok! Yes you can make a pogo pin test fixture with a 3D printer! @SavingWithBabies - you have ESP by the way. Here is my first cut mocked up on the bench. I 3D printed the base for holding the PCB and the overhead pin probe for flashing. The base has ball tip contacts so the board can slip into the sockets effortlessly. The overhead pins are crenulated and will bite into top contacts on the board.

I'm astounded that the 3D printer can hold this precision. The pin diameters are 0.0395". I had to bore out the holes a bit but they are located well enough to test a pcb. These printers will definitely change the test fixture game.

The DE-STA-CO clamp doesn't come straight down but rather in an arc. I think the spring pins will take up the slop though. I'll know for sure when I actually probe a real circuit. The board in the photos is just a dummy for the geometrical setup.

This was just stupid easy. Board fixtures have always been a royal pain for me in the past. Such a great time to be curious about things! I wonder what the implications are of making all these technical tools so cheap and accessible?

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Generation-X
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Re: DIY software development and/or electronics?

Post by Generation-X »

I wonder what the implications are of making all these technical tools so cheap and accessible?
Minimum wage? :lol:

basuragomi
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Re: DIY software development and/or electronics?

Post by basuragomi »

PC Sound card oscilloscope for Linux. Sound cards have a pretty incredible signal to noise ratio, are mostly shielded and have a sampling rate sufficient for many projects short of wifi DSP stuff.

A Windows implementation of the sound card oscope.

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Sclass
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Re: DIY software development and/or electronics?

Post by Sclass »

Wow! Now that is cheap. Basically use what everyone already has. They make great LCR meters too if you can find SW.

Got me thinking of tablet and phone apps. There are a bunch there too.

You can do a lot with sound card bandwidth. It beats flying blind.

So many options.

SavingWithBabies
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Re: DIY software development and/or electronics?

Post by SavingWithBabies »

@Sclass That looks great! I've been wanting to try something like that at some point but haven't quite gotten to a project that would need it. I want to try making some computer input devices (USB HID) so that is next up for me but using Arduino Pro Micro as they have a USB HID software stack all set to go as others are doing the same (for some reason, it's for that specific chip in the Pro Micro). But some day I'll try a pogo pin setup.

Hopefully, with the tools getting cheaper and 3D printer making things easy we'll see some kind of renaissance in small scale manufacturing and/or learning by people in areas that wouldn't have had as much of a chance in the past. I know there are all kinds of divides out there but it does give me hope. Once I get a more permanent living space, I'm itching to get a lathe and a mill to try metal working. That kind of equipment is not very inexpensive unless used and you get lucky or have a good eye/aptitude for inspection but it is well within reach with some effort/time for most.

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Sclass
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Re: DIY software development and/or electronics?

Post by Sclass »

Uh, this was stupid easy @SavingWithBabies. You can knock this together in an hour. It only cost pennies in pins and pennies of filament.

Not sure how useful a pin test fixture is in general. Today we can build a lot of self test into our hardware for pennies. If you need test I/o there’s in circuit debug and pin headers. Fixtures are a last resort when you run out of space or budget. Hey but if you want to build one, dive in. I designed this one in a few hours and had it in my hand in another hour thanks to the printer. It has never been this easy.

USB HID? Lathes and mills? Wow you remind me of my youth.

I almost gave you a spoiler alert but I deleted it. Old engineer rambling about a bittersweet career.

I admire your excitement. Follow your passion and just dive in. This is a great time to dabble in this stuff. The hardware (even tiny lathes and mills) is cheap and plentiful. Invest bravely in your personal projects...they are the only ones you’ll truly own and control.

It’s all there at your fingertips. You can build a bed of nails tester on your printer - tonight. Just reach out your hand and grab it. I did. Thank you for inspiring me to get a 3D printer.

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