Interface ideas?

[PersonX99]

I am somewhat new to hands-on electronics and am looking for some advice/ideas.
I am trying to figure out how to interface from a coil (on a pinball machine. high voltage:20-50v) to an input on a picaxe.

I'm assuming this would require a simple transistor switching circuit that would protect the picaxe input from the high voltage.

Questions:
(1) Is this an effective/safe approach to interfacing a coil with a picaxe input?
(2) If so, what type of transistor and other components could I use to accomplish this?

Thanks for any info that can point me in the right direction towards a solution.

 

[Buzby]

Pinball machines are horribly noisy environments, full of nasty spikes and transients.

I would think your best bet would be to use an optocoupler, thus separating the electronics completely.

 

[AlbertZ]

I am somewhat new to hands-on electronics and am looking for some advice/ideas.
I am trying to figure out how to interface from a coil (on a pinball machine. high voltage:20-50v) to an input on a picaxe.

I'm assuming this would require a simple transistor switching circuit that would protect the picaxe input from the high voltage.

Questions:
(1) Is this an effective/safe approach to interfacing a coil with a picaxe input?
(2) If so, what type of transistor and other components could I use to accomplish this?

Thanks for any info that can point me in the right direction towards a solution.

As Buzby said, a simple switching circuit will not cut it due to the noisy (electrical) environment. We can be more helpful if you can provide more details. e.g.

What is the coil you are referring to? Relay, solenoid or what?

What is the voltage? Is it 20 v, 50 v, steady state, AC or DC?

What are you trying to accomplish with the Picaxe?

 

[Paix]

I am trying to figure out how to interface from a coil (on a pinball machine. high voltage:20-50v) to an input on a picaxe.

Is the coil to be used as a sensor for the Picaxe, or as an actuator? As Busby and AlbertZ have said, more information about the nature of the task are required to be able to put things into proper context. Otherwise we will merely be guessing at what you are thinking of and confusion and wasted effort will ensue.

 

[geoff07]

Take a look at the HCPL3700 and similar optocouplers. The 3700 works with AC or DC, it just requires some current limiting and smoothing, and provides complete isolation.