As seen on Make:, Barton Dring wanted to make something interesting to bring to a hardware meetup, along with learning more about the Grbl Arduino machining package. What he came up with was a pair of drawing robots that are both small enough to fit inside of a backpack, and are used to decorate coasters!

The first of these projects, known as “Coasty,” employs a laser to mark, or even cut, square coasters. They are fed in from the side, then pop out again with a new pattern.

The second device uses a much different method, showing off Grbl’s versatility as a polar plotter. Round coasters are placed on a rotating base, and a pen goes around and around until a new doodle is produced.

Be sure to check out both of these machines in action in the videos below!

Blow guns can be very helpful around your workshop, but sometimes you want a subtle shot of air instead of a full blast. There are several ways to take this on, but YouTuber “MBcreates” decided on a novel method using an Arduino Nano for control.

In his setup, a stepper is used to turn a screw as a linear actuator, pushing an intermediate blow gun’s trigger at progressively more aggressive intervals. This effectively regulates the air flow going into the handheld blow gun, allowing for a more subtle burst of air when needed.

Simple is often better. So I grabbed an old blow gun and used this a valve. The Arduino Digital Air Pressure Regulator uses a NEMA 17 stepper motor to press the lever of the blow gun. A micro end switch was placed against the lever. When the Arduino Nano goes through the setup, the stepper hits the end switch, now the program knows the exact position of the stepper.

The video seen here features some very clever build techniques, and it really turned out spectacular, especially considering it was MBcreates’ first Arduino project!

YouTuber “austiwawa,” apparently not satisfied with other methods of causing mayhem in his garage and backyard, has come up with an innovative disc shooter.

His homemade device uses a brushless motor controlled by an Arduino Nano and an ESC to pull a vacuum belt at high speeds. A clear plastic tube on top holds a stack of about 27 3D-printed discs. At the press of a button, they are then fed one by one onto the belt surface by another motor, which accelerates the disc to ejection velocity and out the “muzzle.” There’s also a potentiometer that allows him to adjust the fire rate.

Although it appears to work quite well, destroying items like an apple and eggs, austiwawa notes that this is only a prototype, and plans to make a fully 3D-printed version in the future. At that point, he’ll release the Arduino code and STL files, making it easy for others to duplicate!

Until then, check it out in action below!

It seems like no one should need to be reminded about the importance of not leaving children in cars, but it still happens. The Fochica project is a Hackaday Prize entry that equips the family minivan with car seat monitors—the name comes from FOrgotten CHild in Car Alert.

It’s an Open Source project consisting of a Bluetooth LE-equipped Arduino that monitors whether the seat is empty or occupied. Paired with a phone app, Fochica monitors pressure sensors and the seat belt’s reed switch to determine whether there’s a kid there. The user’s app checks whether he or she is within Bluetooth range of the car, while also checking whether the kid’s seat is occupied. When the first comes up false and the second true, an alert is sounded.

We could see this technology also being useful for home automation tasks–for instance, reminding you to close the garage door before you go to bed. It’s a great project, and also one of the finalists in the Best Product challenge of the Hackaday Prize this year.

It seems like no one should need to be reminded about the importance of not leaving children in cars, but it still happens. The Fochica project is a Hackaday Prize entry that equips the family minivan with car seat monitors—the name comes from FOrgotten CHild in Car Alert.

It’s an Open Source project consisting of a Bluetooth LE-equipped Arduino that monitors whether the seat is empty or occupied. Paired with a phone app, Fochica monitors pressure sensors and the seat belt’s reed switch to determine whether there’s a kid there. The user’s app checks whether he or she is within Bluetooth range of the car, while also checking whether the kid’s seat is occupied. When the first comes up false and the second true, an alert is sounded.

We could see this technology also being useful for home automation tasks–for instance, reminding you to close the garage door before you go to bed. It’s a great project, and also one of the finalists in the Best Product challenge of the Hackaday Prize this year.

To make a robot, the body geometry and limb design are all done and simulated in the Robogami tool, where different combinations can have a wild effect on locomotion. Once a design is chosen, the end result is a 3D printable flat pack which is then assembled into the final form with a power supply, Arduino, and servo motors.

A white paper is available online and a demonstration video is embedded below. It’s debatable whether these devices on their own qualify as “robots” since they have no sensors, but as a tool to quickly prototype robot body geometries and gaits it’s an excitingly clever idea.

Perhaps there’s an opportunity to enhance the “3D print, then fold” approach Robogami uses with this concept for making flexible prints out of non-flexible material, or incorporating simple 3D printed circuitry.

Thanks to [Adam] for the tip!

To make a robot, the body geometry and limb design are all done and simulated in the Robogami tool, where different combinations can have a wild effect on locomotion. Once a design is chosen, the end result is a 3D printable flat pack which is then assembled into the final form with a power supply, Arduino, and servo motors.

A white paper is available online and a demonstration video is embedded below. It’s debatable whether these devices on their own qualify as “robots” since they have no sensors, but as a tool to quickly prototype robot body geometries and gaits it’s an excitingly clever idea.

Perhaps there’s an opportunity to enhance the “3D print, then fold” approach Robogami uses with this concept for making flexible prints out of non-flexible material, or incorporating simple 3D printed circuitry.

Thanks to [Adam] for the tip!

[Sam Horne] adapted an old school landline phone to deliver clues to birthday party guests. When guests find a numerical clue, they type it into the keypad to hear  the next clue, which involves decoding some Morse code.

The phone consists of an Arduino Pro Mini, a MP3/WAV trigger, and the phone itself, of which the earpiece and keypad have been reused. [Sam] had to map out the keypad and solder leads connecting the various contact points of the phone’s PCB to the Arduino’s digital pins. He used a digitally-generated voice to generate the audio files, and employed the Keypad and Password Arduino libraries to deliver the audio clues.

This seems like a great project to do for a party of any age of attendee, though the keying speed is quick. Hopefully [Sam]’s guests have a high Morse WPM or are quick with the pen! For more keypad projects check out this custom shortcut keyboard and printing a flexible keyboard.

[Sam Horne] adapted an old school landline phone to deliver clues to birthday party guests. When guests find a numerical clue, they type it into the keypad to hear  the next clue, which involves decoding some Morse code.

The phone consists of an Arduino Pro Mini, a MP3/WAV trigger, and the phone itself, of which the earpiece and keypad have been reused. [Sam] had to map out the keypad and solder leads connecting the various contact points of the phone’s PCB to the Arduino’s digital pins. He used a digitally-generated voice to generate the audio files, and employed the Keypad and Password Arduino libraries to deliver the audio clues.

This seems like a great project to do for a party of any age of attendee, though the keying speed is quick. Hopefully [Sam]’s guests have a high Morse WPM or are quick with the pen! For more keypad projects check out this custom shortcut keyboard and printing a flexible keyboard.

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.

If disc shooters are too tame for you, there is always the Great Coil Gun War.