Tuesday, May 18, 2010
by sms
This activity was advised for a archetypal alarm to beam a lamp in a simple sequence: two flashes of 2s with a abbreviate gap of 1s, followed by a best gap of 5s afore repeating the sequence.The 555 timer is affiliated as an astable
Model Lighthouse Project
to accommodate alarm pulses for the 4017 counter. The 4017 has ten outputs (Q0 to Q9) and anniversary one becomes aerial ('on') in about-face as the alarm pulses are received. Outputs Q0, Q1, Q3 and Q4 are accumulated with diodes to aftermath the beam sequence. A transistor amplifies the accepted to ability the lamp, or LED if you adopt (a 470 LED resistor is included on the stripboard layout). The 1M preset controls the time aeon (T) of the 555 astable from about 0.1s to 1.5s, for archetype set T = 1s.
For a altered beam arrangement affix the diodes to amalgamate altered 4017 outputs (Q0-Q9). If the abounding calculation from 0 to 9 is not appropriate one of outputs can be affiliated to the displace ascribe (pin 15). For archetype abutting Q8 (pin 9) to displace (pin 15) reduces the continued gap at the end of the arrangement to 3s (with T=1s).
This activity uses a 555 astable ambit to accommodate the alarm pulses for the 4017 counter.
For advice about lighthouses in the UK appointment www.trinityhouse.co.uk
Parts Required
resistors: 470, 2k2, 22k, 100k
capacitors: 0.1µF, 1µF 16V radial
diodes: 1N4148 ×4
transistor: BC108 (or equivalent)
1M preset, horizontal
6V 60mA MES lamp
MES lampholder
555 timer IC, such as NE555
4017 adverse IC
DIL sockets for ICs: 8-pin, 16-pin
on/off switch
battery clip
9V array box for 6 AA cells
stripboard: 19 rows × 21 holes
