I'm working to create an ultrasonic sensor to be used in object recognition. I've been studying various schematics and current sensors on the market - the most common being the HC-SR04. When viewing these alternatives I've found that several use a hysterisis comparator for their conversions, but this adds a time delay. I was thinking if it could be converted into a strict threshold schmitt trigger it could serve the same purpose without the time delay.
Any experience with this conversion, or an idea of how to make the conversion would be great. Below is a sample diagram from the HC-SR04 schematic for the comparator that would need to be changed into the schmitt trigger.
Any advice on whether a transistor or op-amp solution would be better is also appreciated. Currently leaning toward op-amp as it is easy to design and manage the multiple thresholds necessary for rise and fall edges.