Posted By Ray Dunakin on 11/14/2008 1:11 PM
What are the advantages of using optical sensors to trigger chuffs? I know some systems use this but it seems like it adds an extra layer of complexity, and more potential failure modes. Am I missing something?
Magnetic reed switches have a hysteresis to opening and closing and thus do not react as quickly as an optical sensor. So at high speed the reed switch can miss closing (or opening) per revolution and the chuff could suddenly reduce in speed, become erratic or quit altogether.
The disadvantange of the optical sensor is the need for power to the light source as well as from the sensor... minimum of 3 wires (one shared between the lamp and sensor) instead of just 2 for a plain switch.
At high trigger rates (loco speed) the optical sensor may be able to keep up, but the sound card may not be able to produce the sounds at that rate so it becomes a moot point whether one uses magnetic/reed or optical sensing.
Both systems have failure modes. Dirt on/in the optical sensor can upset the trigger output, but spinning a magnet can produce unbalance and the magnet can pick up metal debris and cause problems that way. Both solve the wear problems associated with a wiper on a rotating contact, but magnetic is seldom vexed with dirt (on the contacts, anyway), whereas the optical can be.
To me it is all a toss up as to which is actually "better" when the many failure modes are taken into account. Some folk may do better wtih one than the other and others will be the opposite. Kinda like the battery/trackpower debate
And just like the battery/trackpower debate, it could all be solved by going Live Steam and you get real authentic sounds! Okay, okay, Live Steam has it vexations too, but given my online name I just had to point it out!