Ben_Taylor
New Member
Hello,
I'm planning on making a simple bike alarm for use overnight in a tent, which will consist of simple components from www.maplin.co.uk and the alarm will be activated if a wire, which will go round the bike and the other end round my wrist while i'm asleep, is broken.
Thus I think the following circuit should suffice?
**broken link removed**
Basically,
"S" is going to be this: **broken link removed** (it apparently 'draws 90ma' so I'm presuming it has its own internal resistor which is why I haven't included one on the emittor)
"W" is going to be the wires that will run round the bike
What I would like to ask from you guys is firstly is does the circuit look ok, and what should the values of R1 and R2 be, and what type of transistor "T" should I use?
I'm planning on making a simple bike alarm for use overnight in a tent, which will consist of simple components from www.maplin.co.uk and the alarm will be activated if a wire, which will go round the bike and the other end round my wrist while i'm asleep, is broken.
Thus I think the following circuit should suffice?
**broken link removed**
Basically,
"S" is going to be this: **broken link removed** (it apparently 'draws 90ma' so I'm presuming it has its own internal resistor which is why I haven't included one on the emittor)
"W" is going to be the wires that will run round the bike
What I would like to ask from you guys is firstly is does the circuit look ok, and what should the values of R1 and R2 be, and what type of transistor "T" should I use?