11

FORGE

Alexa-controlled wheel of fortune

YOU’LL NEED

ESP8266

microcontroller

Continuous

rotation 360

micro servo

(I used the SG90

from Olimex)

Wheel frame,

pointer, and stand

You could make

these out of wood

or cardboard if you

don’t have access to

a 3D printer

Micro USB power

supply

Like the one you get

with a Raspberry

Pi, although most

phone chargers will

probably work

Glue, double-

sided tape, or

Velcro, and some

small screws

There are quite

a few variations

of ESP8266, I

used the ESP8266

NodeMCU LUA

CP2102 WiFi wireless

development

board, this version

works fine with the

Arduino IDE

QUICK TIP

WHEELY GOOD

Print off a wheel design. You can either use the one

we’ve provided, or design your own.

Ours has twelve segments, but you can really

have any number you like. We picked twelve as it

meant it was divisible by three and four, so we could

get extra features on it like the ‘A–D’ and ‘Y/N/?’ in

even measure. Stick the segments to the 3D-printed

wheel or onto a piece of card, 10 cm in diameter. Our

segments were printed onto adhesive paper and cut

out individually, but you could just as easily use a single

design if using card.

Stick a servo horn (our servo came with a large round

one) onto the back, making sure it is central. There’s a

small hole in the 3D print to help align this.

SPIN ME AROUND

Push the wheel onto the servo shaft and check it spins

without interfering with the frame. You can glue it in

place for a more permanent finish.

Connect the servo to the ESP8266 so that the signal

wire (orange) of the servo goes to digital pin four,

and the positive (red) and ground (brown) go to the

corresponding 3.3 V and GRN pins next to D4.

We used Velcro to fix the board to the servo, making

it easy to remove for programming. Wind the servo

cable out of the way, round the servo itself, and you are

ready to program your wheel.

IN DISGUISE

We can configure the ESP8266 to pretend to be a

WeMo device. WeMo are a series of commercially

available lights and switches etc. that can be used for

home automation and can be controlled by Alexa The

real magic in this project is the FauxmoESP library. The

library, written by Xose Pérez (hsmag.cc/wIgBEG)

• based in turn on a Python library written by
  MakerMusings: hsmag.cc/lzVBWu – allows us to fool
  Alexa into seeing the ESP8266 as a WeMo device that
  we can control using voice. The code on the following
  pages is based on Xose’s example code.

Firstly, we have to configure our Arduino IDE

to recognise and work with the ESP board. (If you

don’t have the Arduino IDE you can find it here:

hsmag.cc/cbJELY).

You’ll need to access the board manager from

Tools/Board options in the IDE (the board manager

appears at the top of the list of boards) and add

the library. Full instructions can be found here:

hsmag.cc/IgTabu.

You can select the version you install in the

board manager. At the time of writing, the current

version is 2.4.2; however, we had some issues with

Alexa finding the device with the current version,

and after some hunting around we found that if

you install version 2.3.0 it seems to work fine.

At this point, you can upload the blink example

code (examples are under the File menu in the

IDE) to the ESP8266 to test if everything is correct.

If the code compiles and uploads, then all should

be fine.

THE WHEEL OF FORTUNE

When you say the phrase “Alexa, spin the wheel,” the

wheel spins for a random amount of time, and when it

stops, the pointer will give you your fortune. We can also

use the wheel to give us a random number between 1

and 12 (so it can be used as dice for games), or letter

A–D (there are four in the author’s family, so this is a

good way to resolve disputes or to see who goes first in

a game). It also has a series of Y/N/? symbols, so you can

ask it questions, e.g. “should I go to the shops now?”

Figure 3

Fully assembled

3D-printed frame

and all the other

parts required

NO PRINTER, NO PROBLEM

If you don’t have a 3D printer, this could be made using

thin plywood or cardboard. Cut a piece of thick card

about 3 cm wide and 14 cm long. Fold over the card

90 degrees, 1 cm from each end, to make the back

plate, and cut holes in the back to take the micro

servo. Care will need to be given to make sure the

servo shaft lines up in the middle. Cut a circle about

12 cm in diameter, and cut out the middle, leaving an

empty circle about 10.5 cm. Stick this to the back plate.