Arduino Hacks

3038 Articles

A Bargain In Bionic Knees

April 8, 2022 by 17 Comments

You probably don’t want to lose a leg, but if you have to there are many options now that were unthinkable not long ago. That is, if you can afford them. A microprocessor knee — a prosthetic with some smarts in it — can run anywhere from $25,000 to well over $100,000. However [Lucas Galey], a PhD candidate at the University of Texas El Paso in a recent paper claims to be able to produce a comparable artificial knee for under $1,000. If the paper is too long to read, Amplitude has a good summary including what it means to people who need them.

Of course, the cost of making something like this is almost incidental. The cost of approvals, testing, and other factors mean that even with about $500 in parts, the retail price would be much higher. Probably not $25,000, though.

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Stress-Testing An Arduino’s EEPROM

April 7, 2022 by 29 Comments

Every time one of us flashes an Arduino’s internal memory, a nagging thought in the backs of our minds reminds us that, although everything in life is impermanent, nonvolatile re-writable memory is even more temporary. With a fixed number of writes until any EEPROM module fails, are we wasting writes every time we upload code with a mistake? The short answer is that most of us shouldn’t really be concerned with this unless we do what [AnotherMaker] has done and continually write data until the memory in an Arduino finally fails.

The software for this is fairly simple. He simply writes the first 256 ints with all zeros, reads them to make sure they are all there, and then repeats the process with ones. After iterating this for literally millions of times continuously over the course of about a month he was finally able to get his first read failure. Further writes past this point only accelerated the demise of the memory module. With this method he was able to get nearly three million writes before the device failed, which is far beyond the tens or hundreds of thousands typically estimated for a device of this type.

To prove this wasn’t an outlier, [AnotherMaker] repeated the test, and did a few others while writing to a much smaller amount of memory. With this he was able to push the number of cycles to over five million. Assuming the Arduino Nano clone isn’t using an amazingly high-quality EEPROM we can safely assume that most of us have nothing to worry about and our Arduinos will be functional for decades to come. Unless a bad Windows driver accidentally bricks your device.

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Accessible Arduino Mouse Helps

April 6, 2022 by 3 Comments

We enjoy access to cheap stuff because of the mass market for things like mice, keyboards, and cell phones. But if you need a device that doesn’t have mass appeal, you will have to pay a lot more if you can find it at all. However, with modern techniques like 3D printing and Arduino-like microcontrollers being cheap and simple to use, you now have the option to build that special one-of-a-kind device. Case in point: [Davy’s] mouse for people who have brain or nervous system disorders. This particular device is helping a 6-year-old who can’t manipulate a normal mouse.

The device uses an Arduino Pro and an MPU-6050 accelerometer and gyroscope. The original design uses machined aluminum, but 3D printing should work, too. There’s something wrong with the link to the design files in the post, but it is easy to find the correct link.

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Air Football Looks Pro

March 23, 2022 by 9 Comments

If you are an American, you’d probably think of [Silas Hansen’s] project as “air soccer” but most people will prefer air football. Either way, it is like air hockey but more of a football field feel. The project looks great — if you saw this on the shelves of the local toy store, you wouldn’t think anything of it. You can see a video of the game in action, below.

Unsurprisingly, the brains of the game are an Arduino. The case looks good thanks to laser cutting and 3D printing. A Roland printer produced the stickers that really dress the case up, but you could find another artistic way to do the decoration.

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Your Vacuum Cleaner Follows You

March 21, 2022 by 9 Comments

There are several projects you can imagine where it would be useful to have a robot follow you. For example, we’ve always wanted luggage that would trail us at the airport and we’ve seen several coolers that will follow you. [Madmax95] apparently dream of having a medical cart following a patient, though, and that’s good too. But how do you do it? [Max’s] method was to strip down a Roomba and build a work table and electronics on it. An Arduino controls the motor and communicates with a PC. The PC reads video from a Kinect camera on the robot and uses special tracking software to follow the patient.

We could easily imagine all of this project except the tracking. That depended on a service called Nuitrack. There is a free version that only works for 3 minutes, but it costs if you want to use it practically. However, it would still be cheaper than rolling your own if your time has value.

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An input device combining a joystick with several knnobs and buttons

Modular Multi-Input Macro Keypad Integrates Mouse And Joystick

March 18, 2022 by 12 Comments

While most computer users make do with just a keyboard and mouse, power users often have multiple additional input devices. Gamers use joysticks or dedicated mice, CAD engineers have specialized gadgets for manipulating 3D objects, while graphic designers might want programmable macro buttons to automate various tasks. [Sascha Nitsch] didn’t fancy cluttering his desk with a whole bunch of input devices and therefore decided to combine as many functions as possible into the CIMDIT: a Completely Insane Multi Device Input Thingy.

The main components making up the CIMDIT are a 3-axis joystick module, which can double as a 3D CAD mouse, and a set of buttons, knobs and sliders to enable various functions. One rotary encoder is used to choose an operating mode, while four others can be used as programmable inputs. A small OLED display shows which mode is currently selected, but can also be used to display notifications from various programs.

An Arduino Pro Micro provides a USB interface to a PC and reads out the various input units. The entire design is modular, so it can be customized to any desired combination of analog and digital inputs. [Sascha] made a neat 3D printed enclosure to hold the 3-axis module along with 26 buttons, five rotary encoders and one analog slider. KiCAD files for the PCBs and the FreeCAD source for the enclosure are available under an open-source license on [Sascha]’s Git repo.

The same thing applies to the software driving the CIMDIT, though adding functionality to it might turn out to be tricky: [Sascha] had to perform some serious code optimization to fit everything into the Arduino’s 32 kB of program flash. The Git repo also includes a convenient tool to create key mappings to be programmed into the controller, saving you from having to compose a binary file by hand.

Love macro keypads? Check out these cool examples with gesture detection, an e-ink display or simply beautiful wooden keys.

Rotary Phone MIDI Controller Still Makes Calls

March 15, 2022 by 3 Comments

[Kevin] has long wanted to do something musical with a vintage rotary phone and an Arduino, and has finally done so and committed the first of several experiments to HTML in a five-part series. He found a nice old British Telecom number, but it had been converted to plug and socket wiring to work on the modern system. Because of this, [Kevin] wanted to keep it completely functional as a phone. After all, it ought to work fine until 2025, when pulse dialing will no longer be supported in [Kevin]’s locality.

As you can likely understand, [Kevin] was keen to interface with the phone from the outside and leave the inside untouched. He used a sacrificial ADSL filter’s PCB to break out the socket, and added a pull-up resistor between the pin and 5 V.

Pretty quickly, [Kevin] figured out that when the phone is on the hook, it gives a constant high signal, where as the picking up the phone presents as a high signal going low, and dialing each number results in pulses of that quantity that alternate between high and low. Continue reading “Rotary Phone MIDI Controller Still Makes Calls” →