Suggestions for a hobby DIY project?

[fbs7]

I'm actually an electronic engineer, but never really worked in the field, due to lack of opportunities in my home country. Instead I worked as computer programmer, and I had lots of satisfaction and accomplishment in that field.

Meanwhile I remember that 40 years ago, in my teens, I used to save me money then go to a tiny electronics shop (it was the only one in my city), spend half an hour there browsing through that mysterious stuff, and purchase components one by one - "give a 100-ohm resistor, and one BC548 transistor!", to try and make circuits that I saw in electronic magazines. They very rarely worked! :^)

Now I have some disposable income, and I'd like to catch a breath of my youth again and try my hand in some project of reasonable complexity -- you see, I'm an adult, so something like a little beeper or the old radio will not be satisfactory any more.

So, anyone has some experience or suggestions of electronic projects that you built and found rewarding, say for up to $500 or $1000 -- and hopefully will not take 200 hours to make it work? Something that involved some real building, as opposed to just buying an arduino or beagleboard and writing a program in there?

 

[berkeman]

Well, here are some questions that would help us start to make some suggestions...

• What projects have you built so far? Have you built them from the ground-up, or as kits? If you've never built anything at all before (except for the simple doodling as a kid), would you consider building a couple of kits first to improve your skills and experience?
• What is your level of soldering skill? Basic through-hole, larger SMT (0805+), smaller SMT and fine pitch? What soldering iron(s) do you have? Do you have a binocular microscope for doing SMT assembly? How is your eyesight and how steady are your hands? Do you have a hot-air SMT rework station available?
• What is your experience with programming microcontrollers (uCs)? Have you done any CLPD or FPGA designs before? If so, a combined uC + FPGA project can be quite challenging and fun.
• What are your hobby interests? Are there any projects that you would like to build if you had the abilities? (Hi-Fi, robots, home weather stations, Amateur/HAM radio, etc.)
• Do you have local Mentors available to help you with such projects? A local electronics club or robotics club or Amateur Radio club?

 

[fbs7]

Oh, good questions, thank you for them! :^)

* soldering skills - through hole, up so far, although the idea of conquering SMT soldering does seem incredibly tempting! At this moment I have no equipment of any kind, though, so I'll have to buy everything; I think I'd be more at home with a breadboard project, I reckon, as I don't really have much of what you can call hand skills :^D
* I'm sure I can handle any microcontroller, as I've done a lot of programming in both C and assembly; no FPGA experience, though -- when I went through college there were no such things around -- although I guess I can handle that if needed, as I know both Verilog and VHDL, so I bet I can study and translate that into FPGA
* on areas of interest, I'm looking for inspiration; the idea of building a heart monitor or a digital echo chamber caught my attention when I first thought of it; now you say it, a mini-weather station should be interesting too! measuring say temperature and humidity, I can get that by my computer and actually have an utility for it
* as far as mentors, I'm out of luck - it's just me and my mouse over here :-(

Thank you!

 

[jrmichler]

Back in the 1980's, I made a hearing aid for my father. He got an audiogram that showed high hearing loss at the upper end of the speech frequencies, and near zero loss at low speech frequencies. This explained why he could easily understand me, hear my mother with difficulty, but could not hear the young female bartender at his favorite bar. He knew he needed a hearing aid, but was scared off by a neighbor who had paid $1400 for a hearing aid that he could not use. My dad was not about to spend money for an unusable anything.

So I connected a microphone to an amplifier to an octave band equalizer to a headphone, and set the controls to maximum treble and minimum bass. He could now easily hear me and my mother, he could easily hear my mother doing her Donald Duck imitation, and hear other things that he had never heard before. So I wired up a simple op amp amplifier with a simple bandpass filter. The filter center frequency was set to about 3000 Hz, and the rolloff came out about right for lower frequencies. It was wired on a Radio Shack project board, and fit into a plastic case that fit into a shirt pocket. A tie clip microphone and ear bud plugged into sockets in the case. It worked perfectly although it looked strange, with wires all over the place.

Dad then went to one of those hearing aid places that advertises on TV, and told them what he had learned. They refused to give him his free hearing test and threw him out. So he went to a real hearing aid place, where he was told that he was the first customer who actually understood what he needed. They sold him a pair of hearing aids, one for each ear, for a total of $440. The hearing aids worked perfectly.

I did have some problems with unwanted feedback. A friend, who was a EE, showed me how to solder bypass capacitors from ground pins to ground to make it work.

Do you know anybody that needs, but cannot afford, a hearing aid?

 

[yungman]

I have been an EE and manager of EE for 30 years and retired. Electronics is still my passion. I am almost working part time at home design and build hifi power amplifiers. It is not the highest tech in the world, but when you get to the top, it has it's challenge and going into arts. I've been doing this for over 3 years and still find it interesting.

Mind you this is NOT to be taken lightly, I spent time studying it. Large signal design is very different from the normal small signal circuit design. Simulation programs like LTSpice can only help you to a limited extend, it can become an art.

I go all out in my design, intend to compete with the best. It is not cheap. Just the material cost of one of my small amp is like $900USD. But of cause you can cheapen it. If you are not that familiar with electronics, you can also buy pcb or even kits on ebay. There are a lot of Nelson Pass's Aleph amp kit on ebay that you can try. No guaranty how they work, I just saw a lot of ebay.

If you are interested, I can give you more info...a lot more info! Here is the picture of one of my amp, it's an integrated amp ( with remote volume control). It's a dual monoblock design ( literally two individual amps in one chassis each with it's own power supply and filters). Each channel uses 9 pairs of output transistors.

 

[Borek]

Weather station is painfully trivial - you connect a measuring chip to uC (takes 4 wires), add a display (another few wires), use ready libraries to program everything. Been there, done that: Raspberry Pi Zero W (Arduino would do, but I wanted WiFi connection and http server to make it easy to access the data), BME280, Waveshare E-paper E-Ink 2.9" 296x128px, around $70, can be done much cheaper, I just didn't want to wait.

It can be a good starting point though.

 

[fbs7]

So let me invert the question..

Which hobby projects that you guys did that brought satisfaction at the end? Hopefully something that does not involve building a 30-feet car-eating robot, that's out of my range :^)

 

[yungman]

I am getting a lot of satisfaction for sure, or else I won't be doing it. I am not just coming up with some idea for you, I am living it. After I finish building my amps, I use it. I use it for watching tv in stereo ( I had surround sound, I did not like it, I much prefer in stereo with sub woofer). I watch like 4 hours of tv, the amp is being put to use.

If you put your afford learning, designing, you can actually build something that can compete with the high end amps and bit them. In the high end hifi, amps design have not change since the 70s, it's not something that is fly by night like other high tech. Main thing that change was the availability of faster power transistors in the 80s. All the new Class D and Class H are just mid-fi to me that is cheaper at the mid level. It's is knowledge that will last for a while.

 

[anorlunda]

So, anyone has some experience or suggestions of electronic projects that you built and found rewarding,

That question is too open. Is the the end product that would give you rewards, or the learning experience?
Do you wan't to challenge your design skills, or project construction skills? Does the HW or SW portion interest you most?

 

[jim hardy]

I've long wanted a digital clock with a Roman numeral display.It's almost trivial to program an Arduino to keep TOD in Roman Numerals
but finding a display with enough characters big enpugh to be interesting has been a challenge.

I acquired a box of suitable VFD displays , perhaps a dozen i don't remember
but they're the raw glass units
so i need a circuit board to convert ASCII to multidigit dot matrix that matches their pinout .

This driver would do it I think
https://datasheets.maximintegrated.com/en/ds/MAX6853.pdf
i've used I²C communication before so sort of like that IC.
But a fellow would have to make a board for it.
There are hobby sites that offer 'Design It Yourself' PCB's, google will find them.

Maybe this is a candidate for DIY thread ?

old jim

 

[yungman]

The most important question to OP is what do you like. It's no point of building something that you just play with it for a few minutes after you completed it and put it away. What make you tick?

I was a guitarist long time ago, A few years back, I decided to design guitar amp as hobby, I designed and built two, but after I completed them, I played for two days and have been sitting in the closet since. I don't enjoy playing guitar, they really don't give me satisfaction beyond they sounded really good...and that's it! I use my hifi power amp more than 4 hours a day everyday. I'll enjoy it for years to come even if I move onto other hobby.

Not everything is for everyone, what's work for me doesn't mean it will work for you. If you are the kind that is happy with a sound bar, forget power amp! You have to like the end product, not just build and dump.

 

[Borg]

Have you been to the technology section of instructables.com? You can find lots of ideas with instructions there.

 

[jim hardy]

So, anyone has some experience or suggestions of electronic projects that you built and found rewarding, say for up to $500 or $1000 --

i had a great time building a fluxgate magnetoneter about twenty years ago
actually a pair of them mounted on a four foot plank.
The difference in their outputs tells you when you're near a piece of iron big enough to distort the Earth's local magnetic field.
It would report cars going past my driveway.

A friend and i intended to go searching for ship's cannons in the Florida Keys with it... We'd have used a computer to tie its output ro GPS coordinates... but i retired and moved out of Florida before we got the waterproof case worked out..

I'd like to build another and go hunting for meteors. Some big ones fell around here in 1930.
http://www.encyclopediaofarkansas.net/encyclopedia/entry-detail.aspx?entryID=3716

So - what are the things you do when life's flotsam gives you a few hours between crises ?
What do you daydream about?

Try hobby sites like sparkfun and makezine and ARRL and EAA and Sky&Telescope.
It's a banquet out there.

old jim

 

[fbs7]

Wow, many interesting suggestions, all kindly given! Thank you so much!