Up front I must admit to little hands-on knowledge of modern microcontrollers and their software - I know power engineering and big motors much better (45 years of it).
Now, my question: Trying to get grandchildren enthused about electronics. They love model railroads, so we are building a train monitoring system bit by bit.
Current problem: To detect distance (optionally speed) of a locomotive from a specific track location, without messing with track power.
Control platform: Stellaris Launchpad
Options considered:
- TSOPxxxx with "dumb" fixed frequency oscillator and RF LED on loco - How do I get speed info?
- TSOPxxxx and emitter at trackside, reflection from loco - can get speed by time-of-flight, maybe
- 5 Volt red lasers and break detection by red LED as sensor (the kids love the lasers, so...) - no speed detection without multiple devices per detection location
- RFID tags and a coil at trackside (will identify the specific loco which is a plus) - no speed info
- Ultrasonic distance sensors - Ubiquitous and well supported by netizens, but too broad a coverage angle I suspect
- One of many readymade model railroad products - counter to the purpose of this exercise
So, which of these approaches, or any others, will give me the least grief at the software end, and yet will involve sufficient opportunity to engage 8 to 12 year olds in hands on electronic design with results they can experience? What are the pitfalls to watch out for (besides spilled cola)?
The trains are N-scale (1:160 scale).