EDUTEK HANDY TIMER User manual

EDUTEK LTD visit edutek.ltd.uk
HANDY TIMER
ASSEMBLY INSTRUCTIONS (v3.1 )
Circuit diagram:
ASSEMBLY
There are also assembly instructions available on line as a PowerPoint resentation and in
df format.
To begin with, have
the PCB laced in
front of you as
shown.
Follow the next ste s
in order.
Resistors
R1 1KΩ (brown, black, red) 1
R2 100Ω (brown, black, brown)
1
Ca acitors
C1 1uF ceramic di ed ("105")
1
Semi-conductors
D7 LED 5mm, Red 4
IC1 PIC12F629 1
Miscellaneous
SW1-4
Switch, round blue 1
TD1 Transducer 1
BH1 Battery holder, coin cell 20mm 1
Solid core wire 1
8 in DIL IC holder 1
BEFORE STARTING…
Ensure the soldering iron ti you are using is
cleaned and well tinned. Use a flux-
cored
solder when soldering. Clean it frequently
with a wet s onge and use a soldering iron
stand if ossible.
Use a soldering iron with a thin ti and use
thin gauge solder to avoid bridging any
tracks with solder.
CHECKING COMPONENTS
Check through the arts list and note the
ones that have olarity, as they must be
inserted the correct way round.

WIRE LINKS
Sha e 2 ieces of solid core
wire to fit LK1 and LK2.
When they are soldered,
ush them flat against the
PCB It doesn't matter if
they are a little bend or
crooked, as long as they are
flat.
BATTERY HOLDER
This has two tags that fit
into the PCB as shown.
Ensure it is ushed into the
PCB fully and solder the
tags to the PCB.
RESISTORS
Sha e the wires and insert
the resistors R1 and R2.
Each can go in either way
round.
R1 = 1K ohms:
(brown, black, red)
R2 = 100 ohms
(brown, black, brown)
IC HOLDER
It is not essential, but try to
ensure the notch on the IC
holder is facing
downwards. The IC holder
has very short legs. To kee
it in lace while soldering,,
bend the
legs over
in two
o osite
corners.

CAPACITOR
This is a non- olarised ty e so
can be inserted either way
round.
(may also be
blue in colour)
TRANSDUCER
This is the device that roduces
sound. It can be inserted either
way round.
PUSH SWITCH
The ush switch has a flat
section on the side. This flat
section must
face left,
towards R1.
LED's
There are 4 LED's which must be
soldered the correct way round,
with the ositive (long leg) in the
lower of the two holes. There is
also a flat section denoting the
negative.
To kee the LED's evenly away from the PCB while soldering,
use a 6-7mm s acer through the legs of each LED.

INTEGRATED CIRCUIT
Finally insert the IC itself.
Make sure that all the legs
go into the holder and that
the notch is facing
downwards.
OPERATION
Insert a 20mm 3v button
cell into the battery
holder with the ositive
(metal case) facing
u wards. Try not to ush
it too far in as it can be
stiff to remove.
The Timer should lay a quick tune and chase the LED's. It will then go to slee (shut down
to stand-by mode). In this mode it uses very little ower and extends the battery life
considerably.
To set the time, ress the button once for every 30 seconds required. During timing, every
30 seconds the LED's will count down (if less than 2 minutes) and the timer will bee .
When timing has finished, it will lay a brief tune, flash the LED's and then go to slee ..
To cancel timing, ause until the LED's sto flashing, then ress the button again. This will
cancel the timer and send it back to slee .
The maximum length of time that can be set is 5 minutes - 10 resses.
If the unit fails to work, try the following.
• Check LED's are in the correct way round.
• Check IC and battery are in the correct way round.
• Look for short circuits between ads and remove any excess solder
For further details lease go to www.edutek.ltd.uk/ rojects