I have a customer with a fully automated assembly machine that must run constantly to meet production demands. The problem they are having is the operator is also running other pieces of equipment in the area and doesnt see the andon light. I am trying to come up with a way that the operator can have a indicator light with him at all times that will alert him when the machine goes down. The range of the operator to the machine is less than 100'. Audible isnt an option. First thing I thought of was the little pagers that restaurants give out when they are on a wait. Machine is PLC controlled and the indicator light would need to be battery operated.