A 555 TIMER
PROJECT
FOR KS3/4
DEVELOPED BY
WWW.AJBOX.CO.UK
FOR
WWW.NELC.NET
2010
An electronic circuit
A way to make things move
A variation of a 555 Astable
circuit
The core of an Art project
A way of developing
electronic assembly skills
Battery powers the circuit and a motor
555 chip controls the charge on a
Capacitor
When Capacitor voltage is low (3 volts),
555 switches so the Capacitor charges
up
When Capacitor power is high (6 volts),
555 switches so the Capacitor
Discharges
Length of time to charge and discharge
Capacitor is set by a couple of variable
resistors
555 chip uses the capacitor
charge to decide when to
switch its output pin (3) on
When Capacitor is CHARGING, output
pin 3 ‘sources’ current, lighting the
RED LED
When Capacitor is DISCHARGING,
output pin 3 ‘sinks’ current, lighting
the Green LED AND turning the motor
In the FULL version,
everything is joined to a single
circuit board including the
battery and motor
In the CIRCUIT
Version, only the
Main components
Are ‘Onboard’
This view shows the full PCB as it
would appear if made industrially
Notice it has a white ‘silkscreen’
layer to show where components
are to go
It also has holes and cut-outs to
hold components and fix the
motor in place, these would be
drilled and cut by robots
These PCB’s are expensive to
make in small quantities
This view shows the ‘mask’ layer
It is used to create the copper tracks
that carry the electricity round the
circuit
The final copper tracked PCB can be
created by chemical etching or
cutting processes, from this mask
All black areas on the mask will end
up as copper areas so it is important
to get it EXACTLY right
Keep your Mobile
lightweight and
balanced
Dangler has low
power so will not turn
heavy objects
Think about using
shapes and colours
that look very
different from varying
angles
Sharp mobiles are a
Health and Safety risk
This is the last slide of this presentation about the Dangler
project
Lots more details are included in the worksheets, videos and
guides accompanying it
Please go to www.nelc.net
for a free copy of this projects files
DESIGNED, DEVELOPED AND PRODUCED BY WWW.AJBOOKER.CO.UK FOR NELC - 2010