arduino

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A Disc Shooter For When Rubber Bands Or Nerf Darts Aren’t Enough

August 25, 2017 by 27 Comments

There are times in everybody’s life when they feel the need to shoot at things in a harmless manner. For those moments there are rubber bands and Nerf darts, but even then they feel like mere toys. If that is the point at which you find yourself, then maybe [Austin]’s home-made electric disc shooter can help.

Operation of the shooter is simple enough. A stack of 3D-printed plastic discs is loaded into a tubular magazine, from which individual disks are nudged by a motor-driven cam controlled by the trigger. Once the disc leaves the magazine it reaches a vacuum cleaner belt driven by a much more powerful motor, that accelerates the disc to ejection velocity.

The video below the break shows the gun’s construction, as well as a sequence involving the destruction of plenty of balloons, soda cans, and food items. The 3D-printed ammunition seems to us to be the weak link as in our experience it is inevitable that there is a high ammunition loss rate with these type of weapons, but maybe [Austin] has a line on some cheap filament. Either way, his disc gun looks like the kind of toy that could provide an entertaining diversion for many readers.

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Hackaday Prize Entry: CPAP Humidifier Monitor Alarm

August 25, 2017 by 31 Comments

CPAP (Continuous Positive Airway Pressure) machines can be life-changing for people with sleep apnea. [Scott Clandinin] benefits from his CPAP machine and devised a way to improve his quality of life even further with a non-destructive modification to monitor his machine’s humidifier.

With a CPAP machine, all air the wearer breathes is air that has gone through the machine. [Scott]’s CPAP machine has a small water reservoir which is heated to humidify the air before it goes to the wearer. However, depending on conditions the water reservoir may run dry during use, leading to the user waking up dried out and uncomfortable.

To solve this in a non-invasive way that required no modifications to the machine itself, [Scott] created a two-part device. The first part is a platform upon which the CPAP machine rests. A load cell interfaced to an HX711 Load Cell Amplifier allows an Arduino Nano to measure the mass of the CPAP machine plus the integrated water reservoir. By taking regular measurements, the Arduino can detect when the reservoir is about to run dry and sound an alarm. Getting one’s sleep interrupted by an alarm isn’t a pleasant way to wake up, but it’s much more pleasant than waking up dried out and uncomfortable from breathing hot, dry air for a while.

The second part of the device is a simple button interfaced to a hanger for the mask itself. While the mask is hung up, the system is idle. When the mask is removed from the hook, the system takes measurements and goes to work. This makes activation hassle-free, not to mention also avoids spurious alarms while the user removes and fills the water reservoir.

Non-invasive modifications to medical or other health-related devices is common, and a perfect example of nondestructive interfacing is the Eyedriveomatic which won the 2015 Hackaday Prize. Also, the HX711 Load Cell Amplifier has an Arduino library that was used in this bathroom scale refurb project.

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Hackaday Prize Entry: E.R.N.I.E. Teaches Robotics And Programming

August 23, 2017 by 7 Comments

[Sebastian Goscik]’s entry in the 2017 Hackaday Prize is a line following robot. Well, not really; the end result is a line following robot, but the actual project is about a simple, cheap robot chassis to be used in schools, clubs, and other educational, STEAM education events. Along with the chassis design comes a lesson plan allowing teachers to have a head start when presenting the kit to their students.

The lesson plan is for a line-following robot, but in design is a second lesson – traffic lights which connect to a main base through a bus and work in sync. The idea of these lessons is to be fairly simple and straightforward for both the teachers and the students in order to get them more interested in STEM subjects.

What [Sebastian] noticed about other robot kits was that they were expensive or complicated or lacked tutorials. Some either came pre-assembled or took a long time to assemble. [Sebastian] simplified things – The only things required after the initial assembly of the chassis are: Zip-ties, electrical tape and a few screws. The PCB can’t be disassembled, but the assembled PCB can be reused.

The hardware [Sebastian] came up with consists of some 3mm material that can be laser cut (acrylic or wood) and a sensor board that has 5 IR LEDs and corresponding IR sensors. The chassis can be put together using nothing more than a Phillips screwdriver, and the sensor PCBs are well documented so that soldering them is as easy as possible. An Arduino is used as the brains of the unit.

[Sebastian] has come up with a great project and the idea of a platform like this with a couple of lesson plans included is a great one. He’s released the hardware under an Open Hardware license as well so others can share and add-on. Of course, there are other line following robots, like this miniature one created with analog circuitry, and there are other open source robots for teaching, like this one. But [Sebastian]’s focus on the lesson plans is a really unique way of approaching the problem – one that will hopefully be very successful.

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Latskap Semi-Automatic Liquor Cabinet

August 18, 2017 by 9 Comments

A well-stocked liquor cabinet is a necessity for the classy gentleman or gentlelady who likes to entertain. Having the proper spirits and mixers on hand to make anything from a martini to a sidecar is always a solid way to ensure guests have a good time at your cocktail party. In the past, a beautifully crafted cherry or walnut liquor cabinet was enough to impress visitors with your affluence. These days, if you don’t want to look like a pauper, you have to take it a step further.

[Elias Bakken] and his uncle [Mike Moulton] have decided to take liquor cabinets into the 21st century with a semi-automatic liquor cabinet called Latskap. The project is still in progress, and in the prototyping stage, but their build log on Hackaday.io is showing a lot of potential. It shouldn’t be long before they have a fully functional prototype finished.

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Secret Serial Port For Arduino/ESP32

August 17, 2017 by 19 Comments

If you use the Arduino IDE to program the ESP32, you might be interested in [Andreas Spiess’] latest video (see below). In it, he shows an example of using all three ESP32 UARTs from an Arduino program. He calls the third port “secret” although that’s really a misnomer. However, it does require a quick patch to the Arduino library to make it work.

Just gaining access to the additional UARTs isn’t hard. You simply use one of the additional serial port objects available. However, enabling UART 1 causes the ESP32 to crash! The reason is that by default, UART 1 uses the same pins as the ESP32 flash memory.

Luckily, the chip has a matrix switch that can put nearly any logical I/O pin on any physical I/O pin. [Andreas] shows how to modify the code, so that UART 1 maps to unused pins, which makes everything work. it is a simple change, replacing two parameters to a call that — among other things — maps the I/O pins. You could use the technique to relocate the UARTs to other places if you choose.

If you want to learn more about the ESP32, we covered a good set of tutorials for you to check out. Or if you just want a quick overview, you can start here.

GuitarBot Brings Together Art And Engineering

August 15, 2017 by 10 Comments

Not only does the GuitarBot project show off some great design, but the care given to the documentation and directions is wonderful to see. The GuitarBot is an initiative by three University of Delaware professors, [Dustyn Roberts], [Troy Richards], and [Ashley Pigford] to introduce their students to ‘Artgineering’, a beautiful portmanteau of ‘art’ and ‘engineering’.

The GuitarBot It is designed and documented in a way that the three major elements are compartmentalized: the strummer, the brains, and the chord mechanism are all independent modules wrapped up in a single device. Anyone is, of course, free to build the whole thing, but a lot of work has been done to ease the collaboration of smaller, team-based groups that can work on and bring together individual elements.

Some aspects of the GuitarBot are still works in progress, such as the solenoid-activated chord assembly. But everything else is ready to go with Bills of Materials and build directions. An early video of a strumming test proof of concept used on a ukelele is embedded below.

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Hackaday Prize Entry: Smart Composting System

August 14, 2017 by 14 Comments

Composting serves an important purpose in our society, reusing our food scraps and yard waste to fertilize gardens rather than fill up landfills. Knowing that most people don’t compost, [Darian Johnson] set out to create a Arduino-controlled composting system to make it as simple as possible. It monitors your bin’s moisture, temperature, and gas emissions to ensure it’s properly watered and aerated.

[Darian]’s project combines a MQ4 gas sensor that detects combustible gas, a soil moisture sensor, and a temperature and humidity probe. The nearby water reservoir is monitored by an ultrasonic sensor that keeps track of the water level; a pump triggered by a TIP120 turns on the water. Meanwhile, a servo-controlled vent keeps the air flowing just right.

The Smart Composting System sounds like it would be useful to home gardeners; it’s a Best Product finalist in the 2017 Hackaday Prize.

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