BOO! Teach Arduino Basics With this Fun Ghost

Halloween is just around the corner, and the spooky themed tips are just starting to roll in. If you’re looking to one-up the basic store-bought decorations, and maybe teach your kid the basics of an Arduino while you’re at it — why not build a Peek-A-Boo Ghost!

Using an Arduino, two servo motors and an ultrasonic distance sensor it’s pretty easy to make this cute little ghost that covers its eyes when no one is around. They’re using cardboard for the ghost, but if you have access to a laser cutter at your hackerspace, you could make it a lot more robust using MDF or plywood.

When the ultrasonic distance sensor senses someone coming towards it, it’ll trigger the arms to move — though it’d be easy to add a small speaker element too and get some spooky music going as well!

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Pac-Man Clock Eats Time, Not Pellets

[Bob’s] Pac-Man clock is sure to appeal to the retro geek inside of us all.¬†With a tiny display for the time, it’s clear that this project is more about the art piece than it is about keeping the time. Pac-Man¬†periodically opens and closes his mouth at random intervals. The EL wire adds a nice glowing touch as well.

The project runs off of a Teensy 2.0. It’s a small and inexpensive microcontroller that’s compatible with Arduino. The Teensy uses an external real-time clock module to keep accurate time. It also connects to a seven segment display board via Serial. This kept the wiring simple and made the display easy to mount. The last major component is the servo. It’s just a standard servo, mounted to a customized 3D printed mounting bracket. When the servo rotates in one direction the mouth opens, and visa versa. The frame is also outlined with blue EL wire, giving that classic Pac-Man look a little something extra.

The physical clock itself is made almost entirely from wood. [Bob] is clearly a skilled wood worker as evidenced in the build video below. The Pac-Man and ghosts are all cut on a scroll saw, although [Bob] mentions that he would have 3D printed them if his printer was large enough. Many of the components are hot glued together. The electronics are also hot glued in place. This is often a convenient mounting solution because it’s relatively strong but only semi-permanent.

[Bob] mentions that he can’t have the EL wire and the servo running at the same time. If he tries this, the Teensy ends up “running haywire” after a few minutes. He’s looking for suggestions, so if you have one be sure to leave a comment. Continue reading “Pac-Man Clock Eats Time, Not Pellets”

Laser tracker replays competitive rock wall climbs


Instructables user [PenfoldPlant] is a big fan of indoor rock climbing, and while watching others make difficult climbs, he has often wondered if he could follow the same route up the wall. Unfortunately, aside from watching the other climbers and hoping to remember the path they have taken, he found there isn’t much you can do to ensure that you have precisely replicated the climb.

He thought awhile and came up with a laser tracking system that can be used to record a climber’s ascent, then replay it any number of times. This allows climbers to be able to replicate other climbers’ paths as well as compete against one another in timed races.

This works much like the “ghost” feature found in most racing games, though the process is half manual/half automated. The initial ascent is recorded by manually tracing the climber’s route with a laser pointer as they climb. The path is recorded and then can be replayed, courtesy of the onboard Arduino.

It really is a neat system, and while it works pretty well already, we think there is still room for enhancement. It wouldn’t be extremely difficult to have the climber wear some sort of light beacon that could be tracked using a web cam or other recording device, taking the manual labor out of the equation. In that case however, we imagine the Arduino would need to be swapped out for something a touch more powerful.

Stick around for a quick video of the tracking system in action.

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Halloween props: flying crank ghost


[Jake’s] projects have become regular features here on Hack a Day. He keeps the Halloween hack-fest rolling with his Flying Crank Ghost. For the ghost he used a store-bought skull but sculpted some hands himself out of Styrofoam. The body is fashioned from coat hangers with a bit of creepy fabric draped over the hole thing to complete the look.

He added some very convincing motion to the ghoul using a salvaged microwave turntable motor. The motor is mounted in the center of a two crossed boards, and has an armature attached to it. Three strands of monofilament attach to the end of the armature, run through eyelets on the ends of the crossed boards, then attach to the head, and each arm. When the motor is turned on, the armature turns, moving the head and hands up and down at different rates. Take a look at the embedded video after the break to see the final product.

[Jake] does mention that the motor he used is a bit underpowered. We figure this only needs to hold up for one night, so dig through your junk bin and see if you can throw one of these together in a few hours.

Continue reading “Halloween props: flying crank ghost”

The Old Robots Website


We found The Old Robots Website this morning and ended up spending way too much time there. It’s a display of mainly consumer robots, though there are some custom jobs tossed in there too. Ranging from silly to awesome and everywhere in between, we found tons of great information. By strange coincidence, we saw Arok in a documentary about eclectic homes last night. Arok’s creator explained that not only is he an amazingly versatile robot, Arok is also going to be the medium for communication after his creators death. That makes him even creepier.

[via Robots Dreams]

Ghost matrix, glow printing

Ok, there aren’t any usefull applications we can think of for this one, but we want one really badly. This is a combination of a miniPOV, some UV LEDs, a CNC rig, and some glow in the dark paper. The Ghost matrix works similar to a dot matrix printer where it flashes the UV light to activate the paper. The final effect is very nice. Great job on this one.

[via Laughing Squid]