Part Number: PGA460-Q1
I'm developing a ultrasonic range detector (from 1m to 10-15cm or so) using 3 different transducers (Murata hermetic / closed top) and a PGA460-Q1; the questions are:
1. Is it possibile to "multiplex" these 3 transducers to the only PGA460-Q1 using MOSFETs or something? There's a MPU onboard which has some free output pin to drive the MOSFET gates;
2. The transducers are connected to the PGA460 thru a 10m shielded cable, so I think it'll be better to drive them with a hgh voltage (transformer) - is it possible to use only 1 transformer to power up the 3 transducers (one at a time, btw)
Does anyone has a (working / basic) schematic? Thank you very much!
- Marco Dassi
required range is from 30 ... 40 cm to 1 ... 1.5 m
I saw a device with what I need, but there's no schematic and I don't need the microprocessor of PGA450 (in fact, I'm using a PGA460-Q1); does anyone recognize some circuit topology?
In reply to Akeem Whitehead:
Thank you very much for your clever schematic, you really saved my day!
There's no problem to use half or full-bridge driver, as long as the device works! I like your solution because there's no transformer (bulky, expensive, and needs to be tuned).
There are some problems here (in Italy) to find Murata transducers in small quantities, so I've chose a MCUSD14A40S09RS (closed top, sealed) from Multicomp, which is quite similiar (I hope so).
No problem for the microcontroller, it's already on the board with a lot of free output pins.
This application is for a moving stair, which has to "gently" land on the ground, hence the necessity to know the distance in real time from 3 different points (L, R and center); since the speed of landing is relatively low, I've chose to multiplex the transducer for cost-saving (the evil of today's engineers...)
Just one more question: the board will be powered by 12 ... 24 V DC, what do you think about a MC33063A in step-up mode to make a regulated 30 V DC, independent from the supply voltage? The cables (coaxial) from the PGA to the transducers are 10 m long, I think it's better to be safer than sorry so 30 V DC excitation voltage seems OK to me (and it's PGA460-Q1 limit too)
Again, thank you very much!
In reply to Marco Dassi:
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