Design schematic:
Circuit Number Five uses a SPCO/SPDT relay - but you actually only require to make use of a SPST relay. In case you are going to make use of the veroboard layout supplied - you will require to make use of the style of relay specified. But you are able to develop the alarm making use of whatever style of relay you've accessible.
Circuit Notes:
Any number of normally-open switches might be employed. Fit the mercury switches to ensure that they close when the steering is moved or when the bike is lifted off its side-stand or pushed forward off its centre-stand. Use micro-switches to secure removable panels and also the lids of panniers and so on. When 1 of the trigger-switches is closed - the relay will energize as well as the siren will sound.
You are able to select what will happen up coming. Should you develop the circuit as shown, the siren will continue to sound until you turn it off - or until the battery is exhausted. But, in the event you leave out D3 - the siren will stop sounding right away the trigger-switch is re-opened.
Whilst you are inside earshot of your machine - the former configuration is greatest. You are able to usually turn off the alarm your self. But in case you are going to be away from your bike for any length of time - and you do not wish to trigger a nuisance - then the latter configuration is possibly much more suitable. In the event you consist of a SPST switch in series with D3 - you'll be able to pick the behaviour that finest suits the circumstances at any given time.
Components placement:
Relay coils and some sounders generate high reverse-voltage spikes which will destroy sensitive electronic components. D1 and D2 are there to short-circuit these spikes just before they are able to do any harm. Even though there's absolutely nothing within the alarm circuit itself that might be damaged - I've no concept what other electronic equipment may be connected to the exact same power supply. So I included the two diodes as a precaution. If you are satisfied that there is absolutely nothing on your bike that may be damaged in this way - you'll be able to leave out the two diodes.
