In my project I will be running 2 groups of 2-wire ultrasonic proximity sensors, and I need an inexpensive way to select which group of sensors are connected to the brain. DPDT reed relays are the most strait forward, but they are too expensive. I'm shooting for 50-cents or less per sensor-pair to be switched, and the least expensive relays I've found are well over $1/ea. Are there any ideas?
The sensors are basically piezo elements. The brain sends a pulse to the element which then creates a sonar pulse. The piezo element picks up any reflected pressure waves and converts them back to an electrical pulse that travels over the wire back to the brain. A DPDT relay works perfectly to select between 2 sensors, but they are too expensive.
Here are the sensors:
http://www.aliexpress.com/item/4pcs...dar-detector-NO-LED-display-t/1280888614.html
Thanks in advance for any ideas!
The sensors are basically piezo elements. The brain sends a pulse to the element which then creates a sonar pulse. The piezo element picks up any reflected pressure waves and converts them back to an electrical pulse that travels over the wire back to the brain. A DPDT relay works perfectly to select between 2 sensors, but they are too expensive.
Here are the sensors:
http://www.aliexpress.com/item/4pcs...dar-detector-NO-LED-display-t/1280888614.html
Thanks in advance for any ideas!