Hackaday Prize 2023: This Challenge Makes It So Easy Being Green

This year’s Hackaday Prize is our first nice round number – number ten! We thought it would be great to look back on the history of the Prize and cherry-pick our favorite themes from the past. Last year’s entire theme was sustainable hacking, and we challenged you to come up with ways to generate or save power, keep existing gear out of the landfill, find clever ways to encourage recycling or build devices to monitor the environment and keep communities safer during weather disasters, and you all came through. Now we’re asking you to do it again.

There are hundreds of ways that we can all go a little bit lighter on this planet, and our Green Hacks Challenge encourages you to make them real. Whether you want to focus on clean energy, smarter recycling, preventing waste, or even cleaning up the messes that we leave behind, every drop of oil left unburned or gadget kept out of the landfill helps keep our world running a little cleaner. Here’s your chance to hack for the planet.


One thing we really loved about last year’s Green Hacks was that it encouraged people to think outside the box. For instance, we got some solar power projects as you’d expect, but we also got a few really interesting wind power entries, ranging from the superbly polished 3D Printed Portable Wind Turbine that won the Grand Prize to the experimental kite turbine in Energy Independence While Travelling, to say nothing of the offbeat research project toward making a Moss Microbial Fuel Cell.

Plastic was also in the air last year, as we saw a number of projects to reuse and recycle this abundant element of our waste stream. From a Plastic Scanner that uses simple spectroscopy to determine what type of plastic you’re looking at, to filament recyclers and trash-based 3D printers to make use of shredded plastic chips.

Finally, you all really put the science into citizen science with projects like OpenDendrometer that helps monitor a single tree’s health, and the Crop Water Stress Sensor that does the same for a whole field. Bees didn’t get left out of the data collection party either, with the Beehive Monitoring and Tracking project. And [Andrew Thaler]’s tremendously practical Ocean Sensing for Everyone: The OpenCTD brought the basics of oceanic environmental monitoring down to an affordable level.

Now It’s Your Turn to be Green

If any of the above resonates with your project goals, it’s time to put them into action! Start up a new project over on Hackaday.io, enter it into the Prize, and you’re on your way. Ten finalists will receive $500 and be eligible to win the Grand Prizes ranging from $5,000 to $50,000. But you’ve only got until Tuesday, July 4th to enter, so don’t sleep.

As always, we’d like to thank our sponsors in the Hackaday Prize, Supplyframe and DigiKey, but we’d also like to thank Protolabs for sponsoring the Green Hacks challenge specifically, and for donating a $5,000 manufacturing grant for one finalist. Maybe that could be you?

Op-Amp Challenge: MOSFETs Make This Discrete Op Amp Tick

When it comes to our analog designs, op-amps tend to be just another jellybean part. We tend to spec whatever does the job, and don’t give much of a thought as to the internals. And while it doesn’t make much sense to roll your own op-amp out of discrete components, that doesn’t mean there isn’t plenty to be learned from doing just that.

While we’re more accustomed to seeing [Mitsuru Yamada]’s digital projects, he’s no stranger to the analog world. In fact, this project is a follow-on to his previous bipolar transistor op-amp, which we featured back in 2021. This design features MOSFETs rather than BJTs, but retains the same basic five-transistor topology as the previous work, with a differential pair input stage, a gain stage, and a buffer stage. Even the construction of the module is similar, using his trademark perfboard and ultra-tidy wiring.

Also new is a flexible evaluation unit for these discrete op-amp modules. This very sturdy-looking circuit provides an easy way to configure the op-amp for testing in inverting, non-inverting, and transimpedance mode, selecting from a range of feedback resistors, and even provides a photodiode input. The video below shows the eval unit in action with the CMOS module, as well as highlights the excellent construction [Mitsuru Yamada] is known for.

Looking for some digital goodness? Check out the PERSEUS-8, a 6502 machine we wish had been a real product back in the day.

Continue reading “Op-Amp Challenge: MOSFETs Make This Discrete Op Amp Tick”

Op-Amp Challenge: A Low Noise Amplifier For Those Truly Low Noise Measurements

When something is described as “Low Noise”, it is by the nature of the language a relative phrase. The higest quality magnetic tape is low noise compared to its cheaper sibling for example, but still has noise many would consider unacceptable. In instrumentation however, “Low Noise” has to really mean just that, with a range of specialist techniques to produce circuitry with a truly low noise level for the most demanding of signal applications. As an example [Floydfish] has created a low noise instrumentation amplifier that should serve as a learning exercise for anyone interested in pushing low noise circuitry to the limit.

Anyone who can dredge the hazy recesses of their mind for barely-remembered electronics lectures will know that the overall noise figure of a system is dictated by that of its first component. Thus perhaps the most interesting part of the schematic is at the input, where a row of low-noise op-amps are presented in parallel. We have to admit having to look this one up, to find that it’s a technique whereby the signal outputs of each chip are the same and thus sum, while the noise output of each is different and thus the summed noise output is proportionally lower. This stage is then followed by a buffer and a set of filters for different output frequency ranges.

Our op-amp competition of which this is a part is certainly delivering the goods when it comes to the amny techniques with which these versatile parts can be used. Few of us may need to make such a low noise amplifier, but at least now we’ve learned how.

Op-Amp Challenge: Light Up Breadboard Shows Us The Signals

Most Hackaday readers will no doubt at some point used a solderless breadboard for prototyping. They do the job, but sometimes their layout can be inflexible and keeping track of signals can be a pain. There’s a neat idea from [rasmusviil0] which might go some way to making the humble breadboard easier to use, it’s a breadboard in which each line is coupled via an op-amp buffer to an LED. In this way it can be seen at a glance some indication of the DC voltage present.

It’s an idea reminiscent of those simple logic probes which were popular years ago, but its implementation is not entirely easy. Each circuit is simple enough, but to replicate it across all the lines in a breadboard makes for a huge amount of quad op-amp chips stuffed onto one piece of stripboard as well as a veritable forest of wires beneath the board.

The effect is of a breadboard crossed with a set of blinkenlights, and we could see that for simple digital circuits it could have some utility if not so much for higher frequency or analogue signals. Certainly it’s an experiment worth doing, and indeed it’s not the first tricked out breadboard we’ve seen.

Op-Amp Challenge: Get More From A Single Wire With An Analogue Adder

It’s been a running battle in some quarters for years, whether analog sensor processing is better than digital. Proponents of digital are sometimes driven by lack of familiarity with analog circuitry, while analog die-hards point to delays and software crashes in microcontrollers. We’d probably toe the line that a mixture of the two skills is best, but [paul] has gone full-on for the analog side with his position and limit sensor for a remote telescope. The ‘scope had only one control wire carrying a digital signal, so how was he to get extra information down it? The solution was to overlay a DC voltage, and use a summing network composed of a series of op-amps to encode position and limit data as voltage.

In operation, the circuit is a straightforward DC summing amplifier of the type that op-amps were designed for and at which they excel. We’re not so sure it needs the high-precision resistors and the choice of op-amps seems the wrong way round with the AD8532’s high current output being better suited to driving the line than straightforward summing, but we can see it does the job. If you’re after a demonstration of a DC summing amplifier using an op-amp, here’s your project. Meanwhile if you’re curious about an op-amp inside the black box, take a look at one of the simplest integrated circuit op-amps ever made.

Op-Amp Challenge: Reliable Peak Power Measurement

As part of our Op-Amp Challenge we’re seeing a wide diversity of entries showcasing the seemingly endless capabilities of these extremely versatile parts. Another one comes from [Joseph Thomas], who when faced with the need to measure the properties of an automotive spark plug, came up with a precision peak detector to hold on to the energy level used when firing it.

It starts with an op-amp buffer feeding a diode and capacitor. The capacitor is charged through the diode and holds the level, which can be read through another op-amp. Finally there’s an opto-isolated transistor to discharge the capacitor before a fresh reading is taken.

It’s a simple enough circuit but a very effective one. The op-amps used are bit old-school FET devices, but aside from the high impedance input their performance is hardly critical. Yet another op-amp circuit to hold in reserve should you ever need to perform this task.

Op Amp Challenge: An Ultra-Cheap PH Sensor Amplifier

It’s rare in 2023 for an instrument to be entirely analog, instead it’s more normal for a front-end to feed the analog-to-digital converter (ADC) in a microcontroller. Typically the front-end will do the job of transforming whatever the output range of the sensor is, and present it to the microcontroller in whatever range it accepts. [David] had exactly this problem with a pH sensor, and rather than buy an expensive module to do the job he designed his own.

The sensor in question produces a relatively tiny voltage of -0.414 to +0.414 volts, and requires a very high input impedance. A FET input op-amp is selected, with the ground of the sensor shifted upwards into the positive range by a voltage divider. This then feeds a second op-amp that amplifies the resulting DC voltage for the microcontroller input.

This circuit is an especially simple op-amp application, and is a typical one for a sensor interface where a DC voltage needs to be brought into range of a microcontroller. If you’re not used to op-amp circuits then take a look, this type of analogue circuit is not difficult and might just save your butt some time.

Want to know more about simple op-amp circuits? Have we got the video for you!