I have a degree in electrical engineering and also work as a commerical electrician. I've built dozens of flip-flops and never had a problem. The most important component is the DPDT relay. If you want to know which relay to use, send me an email to [email protected] and I'll send you a pic. One thing not to do is show off by flipping back and forth between the two lights. I've seen people do this and it's dangerous......

Best Regards

DB2004