Analog Anoraks: The Op Amp Contest Starts Now!

We thought it was time to give the analog side of Hackaday their chance to shine, and what’s the quintessential analog IC? The op amp! Whether you’re doing tricky signal conditioning, analog computations like it’s 1960, or just making music sound good, op amps are at the heart of many designs. This contest, starting right now, is your chance to show off what you can do with a good op amp, or a few.

And for everyone else, here’s your chance to dip your toes into the warm analog waters. Whether you’ve always wanted to build a Chua’s chaos circuit or just to listen to music, there’s probably an op-amp project that will fit your personal bill. All you have to do to enter is set up a project on, and use the pull-down menu to enter. We welcome shows of op-amp bravado, naturally, but we’re also stoked to see your simple projects that might help our digital friends leave their world of black and white, and enter into the shades of grey.

Thanks to Digi-Key, our sponsor for the challenge, there are three $150 shopping sprees on the line for the winners. And as always, there are some honorable mention categories to help whet your analog whistle, and to give us an excuse to feature a lot of great projects. You’ve got until June 6, to get your entry in, but these aren’t necessarily simple builds, so get going now.

Honorable Mention Categories

  • Hyper-Precise: If your project calls for, and realizes, high analog precision, we’ll consider it here. Miniscule offset voltages? Ultra-low input current? Crazy slew rates? Show off your most demanding applications here.
  • Oddballs: This is the category for those of you who want to stretch out and try to make op-amps do things that they’re not normally meant to do. We’ve seen them used as motor drivers, for instance. We’ve also seen our share of magic smoke. What’s the strangest op amp circuit? We want to see it.
  • The Classics: This category is for the op-amp applications that are the opposite of the oddballs. Standard situations where an op amp fits like a glove. Part of the value here is in showing folks who are new to designing with op amps where their power lies. Of course we expect to see traditional op-amp circuits here, but surprise us!

The Idea Fountain

Inside a NASA-spec op amp, courtesy of Ken Shirriff

Hard to believe in the digital age, but op amps were once used for math. Multiplication is just voltage gain by any other name, and addition and subtraction are just a matter of picking which pins you use. If you want a real challenge, you can try your hand at an analog computer, or take on a simpler challenge: converting Celsius to Fahrenheit.

Perhaps the op amp’s natural habitat these days is in audio, and there are no shortage of great microphone designs that use them to good effect.

And if you really want to master the op amp, you can always make your own.

Need to brush up on your op-amp theory? For the basic intuition, we really like this video introduction. Al Williams wrote a great piece on op amp simulation, if you don’t like to prototype in solder. And finally, our own Robin Kearey’s piece on the most superlative op amps is a must-read.

The Fine Print

  • All designs must do something with op amps.
  • All entries must be documented with at least a schematic and a demo of the circuit working. Quality of documentation will be considered by the judges.
  • All entrants must agree to have the design published on Hackaday.
  • Employees and contractors of Digi-Key, Supplyframe, Siemens and their immediate family members are ineligible to win, but are still encouraged to enter.
  • Rules and categories subject to change. Judges’ decisions are final, but we strive to be fair.

So get to work on your op-amp containing project today! We can’t wait to see what you come up with. Thanks again to Digi-Key for sponsoring!

(And if you’re waiting for the announcement of the winners of the Low Power Challenge, come back this time tomorrow!)

28 thoughts on “Analog Anoraks: The Op Amp Contest Starts Now!

  1. Thanks for declaring the sponsorship on this post! This is a neat contest :)

    Could you care to clarify the sponsorship situation on ? I honestly just wanted to know whether that was independent editorial content for which HaD received no compensation or whether this was sponsored (absolutely fine with me either way, but it would just be nice to know)?

        1. Thanks; as directly replied to Tom, great to know :) So, but if this is not a sponsored post, there’s no exchange of benefits between Digikey and Supplyframe/HaD for this coordinated effort? Impressive!

          1. We try to be super transparent, and frankly, we’ve got it very easy. Things that look like ads on Hackaday — the stuff in the banners — are ads. Things that don’t look like ads — all the words in the middle — are not ads.

            “Sponsored content” is a euphemism made up by folks who do not uphold the above strict separation, which used to be called “journalistic ethics”. It’s an upside-down world we live in when Hackaday is old-school journalism and the New York Times runs sponsored content, but there we are. Recommended for you!

            Some events, like the Hackaday Prize, these contests, and Supercon, are definitely only possible with sponsorship, and when that’s the case, we always let you know. But that’s events, not articles.

            I suppose you could be confused b/c this is a (non-sponsored) article about a sponsored event? We draw a very thick line internally between the two.

            We work hard on these contests, thinking up the themes, finding examples, and we’ll be judging it in the end, so we really want to see folks put in good entries. That’s Hackaday editorial’s (unsponsored) position, and that’s the sole reason we wrote the article.

          2. @Elliot thanks! You hit the nail on its proverbial head – that’s where my confusion came from. And I know how much work any kind of contest is, and that’s why I was surprised to read you do all that uncompensatedly.

            But with the event being sponsored, this all makes sense. I’ll say it *is* a narrow line you walk when you say “we put a ton of effort into doing A, we also get some money for it, and now we write an independent article about A.”, but such is life of anyone doing anything in public.

            Again, thanks for doing this work – and for being patient with me and this transparent!

    1. This is a good resource, but it’s just TI’s sloppy reformatting of a 1969 Ap Note from National Semiconductor. TI bought NatSemi, so they can do as they please, but many of TI’s datasheets and ap notes don’t hold a candle to the clarity, style, and presentation of the original National stuff.

    1. This is my favorite! You can find it easily online still, oftentimes each chapter separately — it’s like a billion pages long.

      I needed to do something with piezos, pulled down the right chapter, had a working circuit in an afternoon. It’s gold.

  2. For anyone wondering what is the big deal with op-amps, I recommend the book “How to Build and Use Electronic Devices Without Frustration, Panic, Mountains of Money, or an Engineering Degree” by Stuart Hoenig. An oldie but a goodie.

    1. Nope, now you are committed, if you fail to submit a legitimate entry by contest close…
      Well, you won’t like what will happen to you, your family, friends, and neighbors! Not to mention your pets…

    2. Most solutions on Hackaday fall into one of three categories:
      * “Can’t you use an Arduino?”
      * “You can do that with a 555 Timer”
      * “…don’t need a timer, use an OpAmp”

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