I'd go poking around on the ultrasonic transmitter to see if it provides a TTL (5V) version of the 40 transmit signal. If so, I'd hook that up to a cheap OOK (On/Off Keying) transmitter to send a 40 kHz burst of RF pulses. Then the RF receiver and a driver can drive the one ultrasonic transmitter.
Thank you for your response, I'm new to a big project like this, I have done very small projects, So hopefully you can bare with my rookie questions. There's a beggining to everything.
I'm not exactly sure what you ment. Researched what a OOK transmitter is and understand it, but in what portion will I include it in? so your suggesting the xbee wireless would send to the xbee wireless on the transmitter and that voltage will trigger the OOK transmitter to send a 40KHz burst becuase its "1"'s?
I don't think you need anything as expensive as an XBee, do you?
A cheap 418MHz (or similar) Tx/Rx should do the trick (watch out for false triggers from door bells!)
Some of the Devantech serial/I2C ultrasonic devices allow a "listen-only" mode, so don't require any surgery.
A problem I think you may encounter is the relatively narrow acceptance angle of some ultrasound receivers - off-axis reception may not be very sensitive.
Thank you for your response.
Now what do you mean I don't need something like an xbee, i researched and seen its a preferred way and easy to use? a cheaper 418MHz would be just cheaper cost wise right? nthn with making the project better or easier?
But If I remove the transmitter portion of the Ping)) it would just act as a receiver(or would I have to modify more?) or is the Devantech ultrasonic better to use because they use I2C ?
Again all I'm using the ultrasonic waves is to know the pulses so I can trigger the time.
Thank you Both very much!