Arduino Hacks

3048 Articles

How To Build Jenny’s Budget Mixing Desk

February 15, 2023 by 35 Comments

Jenny did an Ask Hackaday article earlier this month, all about the quest for a cheap computer-based audio mixer. The first attempt didn’t go so well, with a problem that many of us are familiar with: Linux applications really doesn’t like using multiple audio devices at the same time. Jenny ran into this issue, and didn’t come across a way to merge the soundcards in a single application.

I’ve fought this problem for a while, probably 10 years now. My first collision with this was an attempt to record a piano with three mics, using a couple different USB pre-amps. And of course, just like Jenny, I was quickly frustrated by the problem that my recording software would only see one interface at a time. The easy solution is to buy an interface with more channels. The Tascam US-4x4HR is a great four channel input/output audio interface, and the Behringer U-PHORIA line goes all the way up to eight mic pre-amps, expandable to 16 with a second DAC that can send audio over ADAT. But those are semi-pro interfaces, with price tags to match.

But what about Jenny’s idea, of cobbling multiple super cheap interfaces together? Well yes, that’s possible too. I’ll show you how, but first, let’s talk about how we’re going to control this software mixer monster. Yes, you can just use a mouse or keyboard, but the challenge was to build a mixing desk, and to me, that means physical faders and mute buttons. Now, there are pre-built solutions, with the Behringer X-touch being a popular solution. But again, we’re way above the price-point Jenny set for this problem. So, let’s do what we do best here at Hackaday, and build our own. Continue reading “How To Build Jenny’s Budget Mixing Desk” →

A vintage film camera with a bright light emitting diode shining through it, next to electronic equipment to measure the shutter speed

Clock Your Camera With This Shutter Speed Tester

February 7, 2023 by 27 Comments

Camera shutter speed is an essential adjustment in photography – along with the aperture, the shutter moderates the amount of light entering the camera. Older cameras (and some newer ones) use mechanical shutters that creep out-of-spec over the years, so [Dean Segovis] built a handy shutter speed tester.

With just a handful of basic components, this project is a great one for beginners to sink their teeth into. The tester is based around a photoresistor that measures light from another source (a flashlight) that travels through the camera body. When the shutter on the camera is released, the shutter speed can be measured and displayed on the OLED screen. An Arduino naturally handles all the computational duties. The whole thing can be easily assembled on a breadboard in just a couple of minutes.

The original project by [hiroshootsfilm] is over on Project Hub, however [Dean] takes a deeper dive with some code troubleshooting, as well as trying out a variety of old film cameras with the breadboard tester. His testing revealed that the photoresistor was better able to detect shutter speed when the camera lens was removed, which is a hot tip for anyone else that wants to try this.

While it’s not surprising that these older cameras are having trouble with their mechanical shutters, this little tester would be an invaluable tool when it comes time to start tweaking shutter mechanisms. If this project has brought out the shutterbug in you, make sure to check out this brain transplant for a Polaroid 100-series Packfilm camera that we covered way back in 2011.

Continue reading “Clock Your Camera With This Shutter Speed Tester” →

Arduino Does SDI Video With FPGA Help

February 6, 2023 by 12 Comments

If you are running video around your home theater, you probably use HDMI. If you are running it in a professional studio, however, you are probably using SDI, Serial Digital Interface. [Chris Brown] looks at SDI and shows a cheap SDI signal generator for an Arduino.

On the face of it, SDI isn’t that hard. In fact, [Chris] calls it “dead simple.” The problem is the bit rate which can be as high as 1.485 Gbps for the HD-SDI standard. Even for a super fast processor, this is a bit much, so [Chris] turned to the Arduino MKR Vidor 4000. Why? Because it has an FPGA onboard. Alas, the FPGA can’t do more than about 200 MHz, but that’s fast enough to drive an external Semtech GS296t2 serializer which is made to drive SDI signals.

The resulting project contains the Arduino, the serializer, a custom PCB, and both FPGA and microcontroller code. While the total cost of the project was a little under $200, that’s still better than the $350 to $2000 for a commercial SDI signal generator.

If you want to play along, the files are out on GitHub. We used the Vidor back in 2018 when it first came out. If you need a quick start on FPGAs, there’s always our boot camp.

A Reverse Polish Calculator For Your Keychain

January 31, 2023 by 24 Comments

As the smartphone has eaten ever more of the gatgets with which we once surrounded ourselves, it’s with some sadness that we note the calculator becoming a less common sight. It’s with pleasure then that we bring you [Nekopla]’s keychain calculator, not least because it’s a little more than a conventional model. This is a calculator which uses Reverse Polish Notation, or RPN.

A full write-up in Japanese (Google Translate link) carries an impressive level of detail about the project, but in short, it takes an Arduino Pro Micro, an array of keys, and an OLED display, and packages them on a couple of fiberglass prototyping boards in a sandwich between laser-cut Perspex front and rear panels.

The RPN notation is what makes it especially interesting,a system in which where you might be used to writing 2+2=  to get 4, in RPN you would write 2 2 + . It allows the use of much simpler code with a stack-based architecture than that used in a conventional calculator. It’s a system that’s usually the preserve of some pretty exclusive machines, so it’s great to see on something with more of the toy about it.

If RPN interests you, then you might like to read our look at the subject, and even feast your eyes on the teardown of a vintage 1975 Sinclair RPN calculator.

Better Macro Images With Arduino Focus Stacking

January 26, 2023 by 17 Comments

If you’ve ever played around with macro photography, you’ve likely noticed that the higher the lens magnification, the less the depth of field. One way around this issue is to take several slices at different focus points, and then stitch the photos together digitally. As [Curious Scientist] demonstrates, this is a relatively simple motion control project and well within the reach of a garden-variety Arduino.

You can move the camera or move the subject. Either way, you really only need one axis of motion, which makes it quite simple. This build relies on a solid-looking lead screw to move a carriage up or down. An Arduino Nano acts as the brains, a stepper motor drives the lead screw, and a small display shows stats such as current progress and total distance to move.

The stepper motor uses a conventional stepper driver “stick” as you find in many 3D printers. In fact, we wondered if you couldn’t just grab a 3D printer board and modify it for this service without spinning a custom PCB. Fittingly, the example subject is another Arduino Nano. Skip ahead to 32:22 in the video below to see the final result.

We’ve seen similar projects, of course. You can build for tiny subjects. You can also adapt an existing motion control device like a CNC machine.

Continue reading “Better Macro Images With Arduino Focus Stacking” →

Arduino Is Out To (Rocket) Launch

January 23, 2023 by 8 Comments

It looks like an ordinary toolbox, but when you open up the Arduino Launch Control System, you’ll find a safe method for triggering model rocket launches. The system uses two separate power supplies. Both must be on for a successful launch and one requires a key. To trigger a 10-second countdown, the operator must hold down two buttons. Releasing either button will stop the countdown.

Besides safety, the controller tracks mission elapsed time and can read weather information from a few sensors. A good-looking build and we like the idea of building inside a toolbox for this sort of thing.

Continue reading “Arduino Is Out To (Rocket) Launch” →

A blue enclosure with "IoT AI-assisted Deep Algae Bloom Detector w/Blues Wireless" written on the front. Two black cables run over a wooden desk to a cylinder with rocks on the bottom and filled with murky water. A bookshelf lurks in the background.

Detecting Algal Blooms With The Help Of AI

January 13, 2023 by 1 Comment

Harmful Algal Blooms (HABs) can have negative consequences for both marine life and human health, so it can be helpful to have early warning of when they’re on the way. Algal blooms deep below the surface can be especially difficult to detect, which is why [kutluhan_aktar] built an AI-assisted algal bloom detector.

After taking images of deep algal blooms with a boroscope, [kutluhan_aktar] trained a machine learning algorithm on them so a Raspberry Pi 4 could recognize future occurrences. For additional water quality information, the device also has an Arduino Nano connected to pH, TDS (total dissolved solids), and water temperature sensors which then are fed to the Pi via a serial connection. Once a potential bloom is spotted, the user can be notified via WhatsApp and appropriate measures taken.

If you’re looking for more environmental sensing hacks, check out the OpenCTD, this swarm of autonomous boats, or this drone buoy riding the Gulf Stream.