I have an application which requires me to break a 24v signal running with low current (60ma being the absolute max). The signal stays on allowing a large hydraulic motor to close a mold with great force. If an obstruction is in the way, it will damage the mold when the hydraulics are activated. The goal is to use a PIC advanced 8 bit microcontroller running at 5v to sense a condition when there is an obstruction and signal the relay to open. My problem is finding the proper normally closed relay and determine how much response time is needed. It would be helpful if the relay could also work of 5 volt power rail and not exceed 0.5 amps of current to open.
Sadly the relay will be need to be placed inside the injection machine and will need to work in a normally closed manner because the object sensing device is only used on one job and will not always be set up to due to space constraints. The object detection system is a vision system to sense plastic parts that get stuck once in a while. It uses a Webcam hooked to a pc that sends a uart packet to the pic to trigger the relay. Currently the injection molding job operates without any protection so fail safe isn't the primary concern. I want to use the pic at 5 volts because I can easily use one DC power rail for the both energizing the relay and powering the pic. I don't have microcontroller experience aside from pic advanced 8 bit running xc8.