PROJECTS: Bike Wheel Wind Turbine
STORM WARNING!
With the electronics assembled, you’re ready to
wind-power your setup! Enjoy your new capacity
as a wind turbine owner.
This wind turbine is meant as an experiment,
a low-cost practical demonstration of how wind
turbines work in principle, for instance in a school
setting. It’s not intended to withstand strong gales
or severe storms. When not in use, or when wind
speeds exceed 6 on the Beaufort scale, it should
be dismantled.
The bike wheel and the mounts for the rotor
blades aren’t designed for permanent operation,
in particular with strong winds. We recommend
you take your own steps to strengthen this design
if you want to make it permanent. (That said, the
construction was more stable than expected. I
left it in the garden all the time, whatever the
weather. Only when a cable tie gave out, the mast
fell over and a blade was destroyed.)
Do you operate a wind turbine? We’d love to
hear from you at wind.turbine@make.co (send
us photos and specs, please). We’ll include your
contributions in a future report.
The Beaufort Wind Force Scale
(Source: Wikipedia, en.wikipedia.org/wiki/Beaufort_scale)
BEAUFORT #
0
1
2
3
4
5
6
7
8
9
10
11
12
DESCRIPTION
Calm
Light air
Light breeze
Gentle breeze
Moderate breeze
Fresh breeze
Strong breeze
High wind, moderate gale, near gale
Gale, fresh gale
Strong/severe gale
Storm, whole gale
Violent storm
Hurricane force
WIND SPEED
< 1 knot, < 1 mph, < 2 km/h, < 0.5 m/s
1–3 knots, 1–3 mph, 2–5 km/h, 0.5–1.5 m/s
4–6 knots, 4–7 mph, 6–11 km/h, 1.6–3.3 m/s
7–10 knots, 8–12 mph, 12–19 km/h, 3.4–5.5 m/s
11–16 knots, 13–18 mph, 20–28 km/h, 5.5–7.9 m/s
17–21 knots, 19–24 mph, 29–38 km/h, 8–10.7 m/s
22–27 knots, 25–31 mph, 39–49 km/h, 10.8–13.8 m/s
28–33 knots, 32–38 mph, 50–61 km/h, 13.9–17.1 m/s
34–40 knots, 39–46 mph, 62–74 km/h, 17.2–20.7 m/s
41–47 knots, 47–54 mph, 75–88 km/h, 20.8–24.4 m/s
48–55 knots, 55–63 mph, 89–102 km/h, 24.5–28.4 m/s
56–63 knots, 64–72 mph, 103–117 km/h, 28.5–32.6 m/s
≥ 64 knots, ≥ 73 mph, ≥ 118 km/h, ≥ 32.7 m/s
The wind speed scale we use today dates back to the 18th century. Originally, it was made to
describe the effects on windmill vanes. British seafarer Sir Francis Beaufort (1774–1857) was
by no means the first to publish such a scale; his work descended from that of civil engineer
John Smeaton (1759) and geographer/hydrographer Alexander Dalrymple (1790). Even earlier
scales were created by astronomer Tycho Brahe (1582), polymath scientist Robert Hooke (1663),
and tradesman, rebel, spy, and Robinson Crusoe novelist Daniel Defoe (1704). But from 1829 on,
Beaufort, who had now been appointed hydrographer to the British Admiralty, shared his scale
with all interested parties. The Beaufort Scale has since become a standard.
MORE WIND POWER PROJECTS:
Otherpower, DIY wind power experts:
otherpower.com/otherpower_wind.html
Simple Savonius vertical rotor turbine:
macarthurmusic.com/johnkwilson/
MakingasimpleSavoniuswindturbine.htm
Easy PVC wind turbine for schools, from U.S.
Department of Energy: energy.gov/eere/education/
downloads/building-basic-pvc-wind-turbine
88 make.co
WIND GENERATOR BLOWBYBLOW
The Chispito Wind Generator is a simple little machine that’s
great for getting started with wind power. In a 30mph wind,
ours gives us about 84 watts, 7 amps at 12 volts.
A diode between the windmill and the battery
ensures that the power only flows in one
direction, charging the battery rather than
drawing power away from the battery and
running the motor. For its diode, this project uses
a bridge rectifier, a component that uses three
or four diodes to convert AC to DC. You could also
use a simple one-way diode, but these usually
aren’t sealed or protected.
When the motor is connected to a load rather than
to power, and you turn the rotor, the field magnets
will induce an electric current in the rotating
electromagnet coils. This is how the motor works
as a generator.
The blades for the Chispito’s
turbine are cut from PVC pipe
— strong, lightweight material
with a gently curving shape
that increases efficiency by
scooping up moving air, rather
than letting it bounce and
blow past.
Pipe and pipe fittings make
up the Chispito’s tower and
mounting hardware. At the
base, a short 1¼" pipe inside
of a 1½" pipe creates a hinge
that allows the tower to be
raised and lowered.
Axle
Rotors
Field magnets
Mast from the Past
In 2006, New Mexico homesteaders Abe and
Josie Connally wrote an excellent how-to in
Make: Volume 05 for building their Chispito Wind
Generator from PVC pipe and an old exercise
treadmill motor (makezine.com/projects/wind-
generator). Three years later, John Edgar Park
built the project on national TV for PBS’ Make:
television; you can follow along with his build at
youtu.be/1vnyYWV78zk.
The Chispito is still popular today — Abe and
Josie later posted the project on Instructables
where it garnered hundreds of comments, and
on their own site velacreations.com, where they
document all kinds of wonderful off-grid DIY
projects. Their solar food dryer, top-bar beehive,
and earth block floors were all featured in Make:
as well (makezine.com/author/abe-connally).
Raised on a mast 10'–30' high, the Chispito
will generate 84 watts of power in a 30mph wind;
be sure to follow the updated instructions for
shaping the blades at velacreations.com/chispito.
Tim Lillis
The Chispito charges up
batteries through a regulator,
which protects them from
overcharging. These same
back-end components could
also store power from a solar
cell array, a micro-hydro
turbine, or any other off-grid,
environmental power source.
89makeprojects.com
PROJECTS:
Pocket Jacob’s Ladder
Mini
Jacob’s
Ladder
Written by Heinz Behling, Translation by Niq Oltman
90 make.co
Heinz Behling
This pocket-sized
ladder is easy to
make for just $20.
You’ll be rewarded
with a real high-
voltage eye-
catcher.
In times past, Jacob’s ladders were often
featured in horror flicks for their decorative
effect. As the bright purple spark climbs between
the electrodes, growing longer as it rises, it
crackles with a sound that says “mad scientist”!
As a spark gap, the Jacob’s ladder also makes a
very good high voltage surge arrester, and they’re
still used for this purpose today, such as on
overhead wires for trains.
If you’re looking for a home-friendly version,
you’ll find one on Thingiverse. Created by
Matthias Balwierz, aka bitluni, it’s all packaged
inside a 3D printed enclosure; you can see it in
action in Matthias’ video at youtu.be/0Dp51Z-
iPF4. More details on this electrifying project
follow below. But first, let’s have a look at how
the ladder works.
91
makeprojects.com
TIME REQUIRED:
1–2 Hours (Plus 5 Hours if Printing)
DIFFICULTY:
Easy
COST:
$15–$20
MATERIALS
» High voltage generator, input 3.6V–6V, output
20kV aka igniter or step-up or boost power
module, AliExpress #32845852439
» 3D printed enclosure (optional) Download the
free 3D files at thingiverse.com/thing:3182601
or github.com/Make-Magazin/Jakobsleiterchen
(see text), or fabricate your own enclosure out of
nonconductive materials.
» Power supply You’ve got two options:
•
AC wall adapter, 5V, minimum 4A, 5.5mm/
2.1mm DC plug such as Adafruit #1466
•
5.5mm/2.1mm DC barrel jack Adafruit #373
— OR —
•
Batteries, 3.2V, lithium iron phosphate
(LiFePO
4
or LFP), size AA (2) such as
AliExpress #32885193856. Don’t use regular
lithium ion (Li-ion) batteries; their output
voltage is too high.
• Battery holder, 2xAA AliExpress
#32860258429
• Charger for LiFePO
4
batteries, AliExpress
#32762060735
» Switch, mini pushbutton, momentary, rated
0.5A 24VAC or higher, ¼" mount such as
RadioShack #2751556
» Solid wire, 0.8mm–1mm diameter for the
ladder electrodes. Previous builds have used
silver-coated copper wire; I used 1mm zinc-coated
steel wire.
» Hookup wire for the circuit. Use copper wire at
least 0.5mm
2
if you’re using the LiFePO
4
cells.
» Neodymium magnet, 8mm diameter, 5mm high
» Terminal strips, screw type
» Empty jam jar, 60mm opening, about 9cm high
» Glue, heat resistant such as epoxy
TOOLS
» Soldering iron and solder
» Wire cutters and strippers
» Screwdriver
» 3D printer (optional)
HEINZ BEHLING is an
editor for Make: Germany
in Hannover who’s into 3D
printing and laser cutting.
He started out long ago on
the Commodore VC20 and
C64; today he’s 60 but still
not an adult.
DANGER: HIGH VOLTAGE! This little
ladder generates very high voltage, up to
20kV. It is unsafe for children or users of
pacemakers or similar implants.
Heinz Behling
PROJECTS: Pocket Jacob’s Ladder
LADDER LOGIC
The functional principle is pretty simple (Figure
A
). A voltage is applied to the ladder electrodes
from a transformer — say, from a neon sign,
microwave oven, or model train, or, in our case,
the output from our little high voltage generator.
If that voltage is high enough, an arc forms where
the gap between the electrodes is shortest. (For
an arc to “make the jump” across the gap, you
need about 1,000 volts per millimeter.) This arc
is simply air that has been ionized by the voltage,
making it electrically conductive. The electrical
energy flowing across the arc is partly converted
to light, heat, and magnetic fields. This causes the
voltage across the electrodes to drop significantly,
as the resistance of the arc provides a load on the
high voltage source.
The arc’s heat — and, to some extent, its
magnetic field as well — cause it to travel
upward. At this point, the voltage is too low to
ignite another arc. As the existing arc travels up,
the widening gap between the terminals forces it
to stretch. Recall that wider spark gaps require
higher voltages for arcing: the arc keeps traveling
until the voltage can no longer sustain it, at which
point it breaks down. With the arc gone, there’s
no load on the voltage source anymore, and the
voltage will again begin to rise. Once it’s high
enough for a new arc to form, the cycle repeats.
Enough theory; let’s move on to practice. For
starters, a word of warning: the Jacob’s ladder
requires high voltage. The voltage boosting
module we use can supply up to 20 kilovolts! Use
great caution when working on this project —
avoid any contact with the voltage. Don’t build this
project if you wear implants such as pacemakers,
insulin pumps, or similar. This build is not safe for
children, either.
The parts are cheap. Including the power
supply (power brick or LiFePo batteries), you’ll
The graph shows the voltage level at the electrodes during a cycle.
How the Jacob’s Ladder Works
TIME
VOLTAGE
Ignition
Ladder ignites Ladder arc goes out
Maximal
operating
voltage
Minimal
operating
voltage
Ladder arc rises
A
92 make.co
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