How to build a Cmos 4060 based burglar alarm system - with a step-by-step construction guide.

COMMENTS SUGGESTIONS	Cmos 4060 Alarm - Testing Your Circuit	MORE ALARM CIRCUITS

Cmos 4060 Alarm Schematic Diagram	The Rest of Ron's Circuits	Write To Ron	More Free-to-Use Circuits	Circuit Exchange International

Cmos 4060 Alarm - Support Material

Introduction

The prototype of this alarm was built using only the Stripboard Layout as a guide. So - if you have faithfully reproduced that layout - you will have a working circuit.

Once you're satisfied that your layout is correct - and you have made a careful and thorough check of the underside of the board - it's time to power-up the circuit and test its operation. This is always an anxious moment. If you construct a lot of circuits - you might consider building the Current Limiting Power Supply - or alternatively - you could add the Simple Current Limiter to your existing PSU. Both will let you set an upper limit on the amount of current supplied to your circuit - and so protect it from any serious damage.

Setup

You can simulate the trigger-switches using short lengths of flexible multi-stranded wire - such as alarm cable. And an LED and resistor is all that's needed to demonstrate that the Siren and Buzzer outputs are working properly.

Details of How to Prepare
The Cmos 4060 Based -
One Time Only Alarm -
For Testing

Turn R6 all the way to the left.

Connect an LED in series with a 2k7 resistor across the Siren and Buzzer outputs. 

I used a yellow and a green LED in the diagram.

You can use whatever colour LEDs you have available. 

Connect two short lengths of wire to the normally-closed terminals.

Strip the insulation from the ends of the wires - and twist them together to simulate a normally-closed loop. 

Finally - connect the DC supply to the input terminals.

Pay particular attention to the polarity of the supply. 

Note that the positive connection goes to the top terminal. 

              ========= 

Turn on the power.

The yellow LED should remain off.

But the green LED should turn on and off at roughly 1 second intervals.

That is - it should be on for roughly half a second - and off for roughly half a second.

This means that the oscillator is working correctly.

              ========= 

When the green LED switches off for the eighth time - it should stay off.

At this stage -  the alarm is in standby mode - and both the LEDs should be off.

              =========

Open the loop for a second or two - then twist the wires back together again.

The moment you open the loop - the green LED should light.

It should remain lit after you close the loop again.

This indicates that the alarm has triggered - and the SCR has latched.

              =========  

About 10 to 12 seconds after the green LED lights - the relay should energize - and the yellow LED should light.

This means that the entry delay has worked properly - and the Siren is now sounding.

              ========= 

After about 7 or 8 minutes - the relay should drop-out - and the yellow LED should switch off.

This means that the cut-off timer has worked - and the Siren is silent.

However - the green LED should remain lit - to indicate that there has been an activation.

              ========= 

Open and close the loop again - as many times as you like - until you're satisfied that the alarm will not re-trigger.

Then turn off the power.

              ========= 

Turn R6 about one third the way to the right - and switch on the power.

The green LED should take about 30 seconds to flash eight times.

More or less 30 seconds is close enough.

              =========  

When you are satisfied with the adjustment - turn the alarm off for a second or two.

Then turn it back on again. 

And - while the green LED is flashing - open and close the loop a few times.

The green LED should continue to flash.

This means that the alarm cannot be triggered during the exit delay.

              ========= 

If the green LED stops flashing and remains permanently lit - it means that the alarm has triggered - and you have a problem.

              ========= 

When you're satisfied that the exit delay has expired - open the loop and trigger the alarm.

The green LED should light and remain lit.

About 30 seconds later - the relay should energize - and the yellow LED should light.

This means that both the exit delay and the entry delay are about the same length.

Turn off the power.

The Buzzer LED and the Siren LED - should both turn off. 

              ========= 

Next - open the loop - and then turn on the power.

The exit delay should begin - and the green LED should flash.

After the eighth flash the green LED should light and remain lit.

This means that - if the loop is open at the end of the exit delay - the alarm will activate.

In other words - if the Buzzer doesn't stop after the eighth beep - the loop is open - and the building isn't secure.

              =========

If You Find a Problem

If - in the course of the test - you find that something is not working properly, then a careful inspection of the relevant area of the circuit board should turn up the cause of the problem. If an LED is not lighting - check that it's connected the right way round. Where you've cut the board to size - look for small loose strands of copper left behind by the saw. Check the board for short-circuits caused by component leads touching each other. It can also happen that the stripboard itself is faulty. I have seen cases where the copper tracks have not been completely severed from one another during manufacture.

If you've built your circuit using the specified components - and you've followed the step-by-step construction guide described on the Alarm Support Page - then the chances are that any bug will be caused by something minor - a component connected the wrong way round - a missing or unwanted solder bridge - an incomplete cut in the track etc. If you haven't used the specified transistors or SCR - check the pin configuration. Just because the components look the same - do not assume that they have the same pin configuration.

If you can't see anything obvious then adopt a systematic approach to faultfinding. Begin by double-checking that all of the cuts in the tracks have been made - that they are all in the right place - and that they sever the track completely. Use a magnifying glass. It only takes the smallest strand of copper to cause a problem. If you backlight the board during the examination - it makes them easier to spot.

When you're satisfied that the tracks have been severed in all the right places, check that you have made - and correctly placed - the five solder bridges. Mark each bridge with a felt-tip pen - or something similar - so that it can be easily identified later.

Next, carefully examine the full length of each track. Look for unwanted solder bridges. Your felt-tip markings will tell you which ones should be there - and help you identify any that shouldn't be there. Again, if you backlight the board during the examination - it makes potential problem areas easier to spot.

If all else fails and you still haven't found the cause of the problem - work your way through the assembly instructions on the Support Page. Check each individual component and link - to make sure that it's present and correctly positioned.

Print out the drawings and mark off the components as you go. Pay particular attention to the orientation of the diodes and the electrolytic capacitors. Take your time and examine each individual component carefully.

Click Here For A Photograph Of The Prototype.

Veroboard Layout	The Rest of Ron's Circuits	Write To Ron	More Free-to-Use Circuits	Circuit Exchange International

Cmos 4060 Alarm - Testing Your Circuit

Introduction

Setup

If You Find a Problem