instructables Ultimate Arduino Halloween Instructions
- June 9, 2024
- instructables
Table of Contents
instructables Ultimate Arduino Halloween
This is not a stand-alone Instructables. Its purpose is to serve
as an overview and intro to the “real” Instructables linked below. This avoids
repetition and mistakes and you can skip it if you have no interest in the
overview of our Halloween projects. Each of the linked Instructables is stand-
alone but will make more sense in the context provided here.
Its other purpose is to share our experience with various components; servos,
relays, circuits, LEDs, etc. None of it is authoritative but hopefully it will
make you aware of things that you previously had not considered.
This is a themed Halloween display. All of the props have a link back to a
notable scene, character, or prop from a scary or Halloween movie. Admittedly
a few of them are a stretch but that’s called artistic license. There are no
slasher movies that make the cut. This is intended to entertain kids even if
their parents need to identify some of the movie references.
We are a father/daughter team, both computer engineers, who share the
engineering and computer programming. She does virtually all of the artistic
work. Virtually everything is homemade including most of the costumes,
artwork, and masks. All of the animatronics and programming are home-built as
well. There are no live action players, all of the characters are animatronic
props.
The first display was set up in 2013 and it has grown every year since.
Originally Stephen King based, it expanded into Halloween and scary movie
(with a little TV tossed in) themed. Before an exhibit is added, it first must
meet the theme requirement. Ideally we look for some recognizable scene that
everyone knows about even if you never saw the movie. In the case of remakes,
the original is better even if the remake broadens its appeal and recognition.
The second criteria for addition is can we make it cheaply. There are a lot of
great ideas but many of them would require specialized items that would blow
the budget. Home Depot is a big source of study and anything that can be
repurposed or rescued from scrap is a big plus. And lastly it needs to be
broken down for storage for 51 weeks. While we build and tweak all year, most
of the displays are only out for a week.
Mostly, we set up and move inside each night. So as we build we look to
include portability, self-containment, and durability.
Most of the props are driven with Arduinos. Some use one, several require two
to offload different functions. Currently we use Pro Minis, Unos, and Megas.
Pi Zero-W is being added now.
Below is a cameo description of each of the exhibits. As Instructables are
added, we will include their links. Comment here if you’d like to see a
particular one written up. We are getting to them as we can.
Before the cameos, we’ve offered some observations, insights and lessons
learned. Feel free to disregard if you have had a different experience or have
a different opinion.
Steps
Step 1: A Brief Discussion on Sound Modules
Most of our projects use embedded sound; might be a memorable quote from a
movie (“Danny’s not here Mrs. Torrance”), a longer quote (“The Raven” by Edgar
Allen Poe), or much longer musical or soundtrack scores. Since they are tied
into other actions, motion sensors etc, they need to be integrated with and
controlled by the underlying micro controller. If you’re just looking
for.background music or creepy sounds, make it easy on yourself and use the
music player tucked in the back. But if you plan on doing anything beyond
that, you’ll need to fool around with the sound modules that are available.
There are a bunch of options; sound shields run in the $20 range but are quick
and easy to set up and use. We opt for the$3-$5 module and suck up the extra
work to setup on the assumption that we can use what we learned over again. We
have been experimenting with different modules which means different code,
libraries and approaches but there are a lot of lessons learned. This is not a
primmer for these modules; there is a lot of info out there on each one.
Common across all of them is the ways they operate. Most are 16 pin, need 5V
(some are 3V even within the same module so pay attention), ground, have 2 to
4 speaker pins, and one BUSY pin. The remaining pins are KEY pins and operate
like pushbuttons. Drop an input to ground to a pin and it plays the
corresponding file. That is generally referred to as KEY mode. The
corresponding le to the key1 pin is the rst le on the device; that may be the
rst one copied or it may be alphabetically. Trial and error prevails here.
Easy to determine if you only need one le. Generally you do not need a library
installed if you you are using KEY mode. Its easy and straightforward.
The other mode is serial and some of the modules have dierent serial options
but essentially you install a library,
congure a TX and RX between the MCU and the sound module. More complicated and
trickier to setup but more a
exible programming option.
All of them have a BUSY pin which just tells you if the module is playing or
not. If using a library, there is probably a function call which returns a
T/F. Handy for while loop control when your music is playing. If going KEY
mode, simply read the pin; HIGH probably means its playing.
Not all sound formats are created equal. These may come up as MP3 players but
don’t believe it. Some only play WAV
les, some MP3 les, and one uses an AD4 format. They are all picky about types
of encoding and bit rates. Don’t expect to simply copy a le and go. If you
don’t have Audacity, get it; you can expect to resample les. Use the lowest
bit rate that sounds good and is supported by your module. That reduces
lesize.
Don’t be fooled by advertised storage. These always (?) are advertised in
terms of megaBITS not megaBYTES. So a 8Mb –usually listed as 8M — module will
hold only 1MB of sound. Not a problem for a few small sounds but you’re not
getting a 3 minute song on it.
The onboard amplifiers here can drive a small speaker but don’t expect much.
Add an amplifier or use old powered computer speakers. Generally they all
provide both DAC and PWM speaker outputs.
Our furst foray into sound was the WTV020-SD. There are a couple of versions
and they are widely available on eBay. This player uses a microSD card for
storage. I would avoid this at all costs. While cheap, they generally only
work with 1G cards and are very picky about the card. You can’t buy legit 1G
cards anymore and the knockoffs don’t seem to work. If you have an old phone
that used a 1G card, you might be able to recycle it here but while
convenient, the SD card is a problem for these modules. It also uses AD4 files
so you’ll need to convert WAV les to use it.
Next up was the WT588. There are three versions. The 16 pin version and one of
the 28 pin versions do not have an onboard USB port. You need a separate
programmer to load files. Not a huge problem if you are using multiple WT588s
like we are; the programmer is only 10 bucks. The USB version is only on the
28 pin package so its a bit bigger. These are pretty nice; play WAV files and
are easy to use in your project. The software to load files is clunky though.
There are plenty of videos out there on how to load files. Its kind of comical
starting with the Chinese interface (there is an option for English but its
not saved session to session) and you can’t use the full keyboard in your file
name. The software doesn’t know about “E”s and other characters for example.
These are available in multiple memory sizes; generally get the largest you
can find. The price difference is trivial.
Our current favorite seems to have gone out of production. Its the MP3FLASH-
16P. There are still a few out there but I’ve only come across a 16Mb (2MB)
version. The USB port is onboard; plug it in to your computer and it shows up
as removable drive. Too easy. It also plays MP3 files in stereo which is a
huge plus for us. These are pretty straightforward to use but there is only a
Chinese manual for it.
There are a couple of others out there. We will eventually give them a shot.
Step 2: A Brief Discussion on Servos
Avoid using USB power when using servos. Servos draw a lot of current in very
brief spikes. They can draw more power than USB typically supports and can
cause erratic behavior of the Arduino. (one servo probably won’t give you any
issues). In extreme cases, its possible to damage the USB host in addition to
the Arduino. The first indication of trouble will be the COMM port dropping
offline from your host as the servo moves.
We add a 470 microfarad capacitor when using servos. Wire it in parallel with
the servo from ground to the 5V servo power. It smooths out the power draw and
we noticed that our sound processors behave better without the power flux
caused by the servo. If you have one servo triggered by say a motion sensor,
don’t bother with the capacitor especially if you are powering through the DC
barrel connector.
If you have a lot of servos in your project, consider using a second power
supply for just the servos. Remember to tie the grounds together or you will
see very erratic results. A servo/motor shield generally supports more servos
as well as DC motors and has the circuitry to provide stable power to the
Arduino through the Vin pin.
Step 3: A Brief Discussion of LEDs
There are lots of references on how to use LEDs in your projects. A great
source for helping is this led wizard. It will help you decide on the correct
led and resistor sizes in a basic circuit.
For anything more complicated, pre-built modules are the way to go. We like
Adafruits’s Neopixels. Lots of options in terms of size and configuration.
They are based on WS2812, WS2811 and SK6812 LED/drivers, have great library
support, and are readily available. There are other options out there that use
the same addressable hardware. Make your choice based on what your project
needs.
If you are just looking for straight illumination, go with cheaper LED tapes
that are not addressable. They just need power attached and can be turned on
and off with relays/MOSFETs.
LEDs can draw a lot of current. Yes you can power them from an Arduino. Too
many will cause erratic behavior from the MCU and can damage equipment. If
using more than a few, provide separate power and remember to tie the grounds
together. Do the math ahead of time; calculate the current needed before you
hook it up. As with servos, avoid USB computer power and use a separate power
supply.
For the Pumpkin Patch, we ended up using MakeBlock RGB LED modules. They use
the same chips as the Neopixels (WS2812, WS2811 and SK6812 LED/drivers). In
fact there are lots of options that use these chips. Pay attention to what you
are buying and what your project needs. . We chose the MakeBlock simply
because of the form factor. They have 4 LEDs/module and had an integrated RJ25
port which made cabling 30 pumpkins much cleaner. We were going to add RJ
ports to Neopixels and these turned out to be a bit cheaper and less work
since they came already assembled.
We used 30 wires to 30 pumpkins. That was solely based on physical layout. We
could have just as easily used 1 wire in a continuous stream to all the
pumpkins but that would have required a pumpkin to pumpkin connection which we
did not want.
Depending on your requirements, SPI or I2C based leds may provide a better
form factor or software advantage. Again, it all depends on your project.
Addressable LEDs use memory and it adds up. Each of our individual LEDs uses 3
bytes of available RAM. Between the program code and dynamic RAM to do what we
wanted with the Pumpkin Patch, we blew out of memory multiple times before we
found an approach that worked. We also had an undesired side effect with these
LEDs. In order to get the precise timing done when addressing them, the
library affects interrupts and these in turn affect the internal Arduino
clock. Bottom line is that Arduino functions that use the clock are
unreliable. There are ways around it but we went with simple. We rigged up a
Pro-Mini to supply a 1 second square timing wave to the Mega and triggered off
of that wave vice the internal clock.
Step 4: A Brief Discussion on Electricity
This is not a primer on circuits and electricity. These are some observations
and things that need to be mentioned. First off, if you are unfamiliar with
the concepts of basic circuits, then you need to get up to speed before
jumping in to any project. Even the simplest Blink example will make more
sense if you know the terms and components referenced.
Alternating Current (AC) is what is available in your wall outlet. Direct
Current comes from wall warts, batteries, and computer power supplies. They
are very different, have different rules, and are used in different ways.
Most of the circuits we use are low voltage, low current, DC circuits. You’re
not likely to hurt yourself by doing something wrong. You may fry some
components but won’t be burning the house down. Your USB connection delivers
5V DC. A wall wart into the DC barrel jack typically is 9V. The wall wart
performs the conversion of AC to DC power. If recycling an old phone or camera
charger to power your project, ensure it meets your power requirements. Look
for the output rating printed on it. We target 2A DC output for our pi and
Arduino projects. A new one runs less than $10. Same thing if using a battery
pack. Make sure you have a configuration that delivers both the correct
voltage and current .
We have a bunch of wall warts from Enercell that we got when Radio Shack was
closing; 90% off; couldn’t bear it. We have them in a wide range of voltage
and current combos and they use interchangeable tips so they are very handy.
They were a Radio Shack brand but there are still some offered online. If you
find one, the barrel connection on the UNO uses an “M” tip. The convention to
use when making connections is RED for 5V, ORANGE for 3V, and BLACK for
ground. We tend to follow that religiously and never use those colors for
anything else.
AC circuits are another story. Its potentially dangerous and the net is full
of bad examples of wiring. Don’t approach AC circuits unless you are familiar
with what you are doing.
Can you use an old computer power supply? The short answer is yes but….. For
most purposes you don’t need the power it can provide and its not worth the
work to tie in the wires to your project. That said, we do use them and in
fact have bought new ones because we ran out of old ones. They are cheap ($15
for a 400W version), deliver plenty of amps at 3, 5, and 12V and are easy to
find. Why use one? If the project requirements tell you you need to. For
example, the Wedding Clothes project uses 4 solenoids to control 4 pneumatic
circuits. They are 12V DC and each draws 1.5A. That’s potentially 6A and 72W;
not getting that from a wall wart. It has LED tapes that also run at 12V plus
all the normal 5V requirements in an Arduino project.
How do you turn things on and off? Use a relay. A relay acts exactly like a
switch. When choosing a relay, you absolutely must be aware of the power
requirements of the device you are cycling. Is it AC or DC; not all relays
support both. How many amps will the load draw? What are the power
requirements of the relay? Is it triggered on active HIGH or LOW? If using
mechanical relays, we power them separately from the Arduino. If using solid
state, not really necessary to give them separate power. An option for DC
circuits (like for some LED applications) is a power MOSFET. Look for pre-
built modules rather than making your own.
There are a bunch of relay modules out there. They come as single units all
the way up to 16 on a single board. Most of the solid state relay modules
(SSR) do not support DC circuits. Look carefully before buying. The advantage
to SSR is that they are silent, will last forever as they have no moving
parts, and are a good buy in low amperage versions. As the amps go up, their
price goes up fast. Mechanical relays (basically magnetic switches) are noisy
when they activate (there is a noticeable click), will wear out eventually,
and have a higher power requirement than SSRs. These small modules though can
control a lot of power for a relatively low price. The ones you typically see
everywhere use a small rectangular cube relay made by Songle. They are blue in
color. We have had terrible luck with them and refuse to buy them. At least
one on each module has prematurely failed. Look for the ones that have a relay
made by Omron. Its the same footprint, black in color, and infinitely more
reliable. They cost more too. Omron relays are typically the ones seen on the
SSR modules.
Things to know when selecting a relay module: AC or DC. control voltage (5VDC
or 12VDC), default setting (NO-normally open or NC-normally closed), max
current rating (typically 2A on SSR and 10 on mechanical), max voltage, and
active
(HIGH or LOW).
The single biggest error floating in the Internet examples is probably the
wiring of AC relay circuits. Everyone wants an IoT device running something at
home. When wiring a relay always switch the load not the neutral. If you
switch the load, there is no current to the device when the relay is off. If
you switch the neutral, there is always power to the device which can result
in injury or damage if you or something else touches it and completes the
circuit. If you don’t understand these term, you shouldn’t be working with AC
circuits.
Step 5: The Shining – Come Play With Us (2013)
The original display. This is a full size walk through of the scene where
Danny is riding his trike in the hallway and sees the ghosts of the Grady
twins. Its full of lots of Easter Eggs and include a picture of the same scene
done in Peeps for the Washington Post. Uses motion sensors and simple sound
cards with the appropriate phrases.
https://youtu.be/KOMoNUw7zo8
Step 6: The Shining – Here’s Johnny (2013)
Motion sensor activated, Jack Torrance’s face comes through the broken
bathroom door and utters his iconic phrase. Not scary but startles the adults
(it is above kid level) as the head bangs the broken door. Uses an Uno
controlled PIR motion sensor and sound card to drive the servo driven head.
https://youtu.be/nAzeb9asgxM
Step 7: Carrie – the Prom Scene (2014)
A bucket of continuous blood pours over Carrie as she stands in front of the
senior prom backdrop. Uses a re-purposed swimming pool pump and a big plastic
tub for one of the classics. TIP: Fake blood has a tendency to foam up. Add
spa defoamer (available at swimming pool and hot tub dealers) to keep it from
foaming and ruining the effect.
https://youtu.be/MpC1ezdntRI
Step 8: Misery (2014)
Our simplest and one of the early additions. Plans are to have the Annie
Wilkes skeleton swing a hammer at the Paul Sheldon’s ankles. Just haven’t
quite gotten to it.
Step
9: It – Pennywise the Clown (2015)
Don’t ya want a balloon? This one is pretty creepy. Watch the animatronic eyes
follow you around the corner.
Step
10: The Exorcist – Reagan’s Head Spinning (2016)
A true classic and surprisingly easy to do. An Uno, a stepper motor and driver
and a sound card. The nightgown was purchased (pea soup vomit stains included)
but the face makeup on the styrofoam head is all hand done.
https://youtu.be/MiAumeN9X28
Step 11: Beetlejuice – the Wedding Clothes (2016)
Remember Otho reading from The Handbook for the Recently Deceased and the
reanimated wedding clothes on the dining room table? This is it. The two
mannequins are infracted with an air compressor as Otho reads. This uses both
an Uno and a Pro Mini, has 4 pneumatic circuits, 6 DC circuits, 4 AC circuits
and more are planned to make them rise off the table. Adds a compressor and
vacuum for a real crowd pleaser. And check out Otha’s book; you can buy
anything online.
Step
12: Ouija – the Ouija Board (2017)
No random movements. Capable of spelling anything from a keyboard or running
in automate with a second Arduino pushing in pre-stored phrases. Stepper
motors and some clever programming made this a hit when it debuted. This can
be built for under a $100. See the full Instructables here.
Step 13: The Raven – Vinnie (2017) – VOTE
More about the Poe short story than the 1963 Vincent Price film, this is a
full size skeleton who, in Vincent Price’s voice, reads the Raven aloud. This
is not your $15 talking skull from a discount store. All home built, it
processes sound files live and programmatically determines the jaw movements.
Currently its being expanded and modified to work with more skulls and live
radio broadcasts. See the full Instructables
https://youtu.be/dAcQ9lNSepc
Step 14: Hocus Pocus – Book of Spells (2017)
Compare at $75 on Amazon without the animatronic eyeball. Handmade out of an
old router box. Give it a tap and wake up the eyeball.
https://youtu.be/586pHSHn-ng
Step 15: Haunted Mansion – Madam Leota (2017)
A simple Pepper’s Ghost with a 7” tablet and a hollow globe. Cheap and easy,
there are lots of articles out there on how to build it. Best viewing was to
put it on a high table.
https://youtu.be/0KZ1zZqhy48
Step 16: Pet Cemetery – the NLDS Cemetery (2017)
This is admittedly a stretch but…… Look at the sign; Pet Cemetery style and
font only changed to NLDS to capture our misery of the Washington Nationals
giving up the Division Series in 2012, 2014, 2016, and 2017. (It’s a different
choke in 2018). One headstone for each year along with an exposed coffin and
NATs flag. Mainly all pink board from Home Depot.
Hard to find in mid to late October if you’re interested in a graveyard theme.
Step 17: The Ring – the Telephone Call (2017)
This uses a telephone circa 1940, with a Pro Mini and two sound module to ring
and playback the infamous “7 days” line. We needed two sound modules because
we wanted the ring to come from the phone body and the voice to come through
the speaker handset. The Arduino interfaces with the 80 year old phone through
the speaker, handset, and cradle hook to know when its answered. The only
problem was the number of kids who did not know how to answer a phone or hold
it to their ear.
See if you can identify the people in the picture. Its not related to The Ring
but is very much Halloween related and is one of the many Easter Eggs
throughout the display.
https://youtu.be/A_58aie8LbQ
Step 18: The Ring – Samara Climbs Out of the TV (2017)
Remember the dead girl from the well climbing out of the TV? She doesn’t climb
but does turn her head to look at you. We were surprised by the number of
pretty young kids that recognized this one.
Step 19: The Pumpkin Patch – NEW FOR 2018 – VOTE
Not brand new but certainly kicked up a notch. The daughter half of the team
loves to carve pumpkins. They typically stick in the theme as well. Over the
years, she started adding foam pumpkins because of their relatively longer
life. These are not your typical Jack-O-Lanterns and this is not a tutorial
about carving. For 2018, they have been set to music with RGB LEDs. In its
scripted mode, the various pumpkins illuminate in time with the music which is
a composite of sounds and music from many movies and shows. As each
sound/music bit plays, the appropriate pumpkin(s) illuminate. In organ mode,
it processes any music and lights up different “bands” of pumpkins in
different colors, all synced to the music. See the Instructables COMING SOON.
See the gallery of pumpkins here.
Step 20: Snow White – Mirror Mirror – NEW FOR 2018 – VOTE
Our first digital effect, we recreated the iconic scene from the movie and
added a few others. This is also our first use of a Raspberry pi Zero, Version
1 is pretty basic and straightforward; look for lots of additions in years to
come. View the full Instructables
https://youtu.be/lFi4AJBiql4
https://youtu.be/stVQ9x5SBi4
Step 21: 2019 and 2020 Updates
We added nothing in 2019. Weather was terrible and the Nat’s won the World
Series so we are at a lot of playoff games. For 2020 we did a much scaled down
Covid version and added the Sandworm for giving out candy
Step 22: New for 2021
We added a lot of real estate to the display this year. We found a bunch of
old items at auction that we added tech to and will summarize here. As we have
time to post specific write-ups we will.
The Radio Broadcast. October 30, 1938 was the original broadcast of War
of the Worlds which caused all the issues in New York and New Jersey. We have
the original Orson Wells broadcast playin on a vintage 1935 Philco radio.
Mommy and Baby. The pram is about 110 years old. When we found it, it was
perfect. A few holes in the top, the metal sides show wear and fading, and it
still rolls pretty well. Mommy is wearing a dress circa 1930s and baby has a
christening gown from around 1930.
The Horror’s TV.. This is a 1950 RCA Victor cabinet. We 3D printed new
knobs, added a Pi Zero, an Arduino Uno and a LCD TV to get whatever we want on
it. The channel changer knob rotates as channels change
Baby in a Rocker. An old dress recycled from a friend who wanted it to
find a good home. Next step is to use a linear motion actuator to rock the
chair.
References
- Yours for the making - Instructables
- Smithfrank's Profile - Instructables
- Ultimate Arduino Halloween : 22 Steps - Instructables
- Jackolanterns - Kim Smith
- Arduino Ouija Board : 8 Steps (with Pictures) - Instructables
- Intelligent Talking Skull -- Vinnie : 9 Steps (with Pictures) - Instructables
- Magic Mirror on the Wall : 8 Steps - Instructables
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