PGA450-Q1: Ultrasonic System Assistance

Casey Pullman

Part Number: PGA450-Q1
Other Parts Discussed in Thread: PGA460, MSP430F5529, CC2650, BOOSTXL-PGA460

I am very new to TI products and need a lot of assistance. I am building a product with ultrasonic transducers housed in a sphere like casing (4-5 in. diameter) which will be attached to an object that will slowly move (forward & backwards and forward/back at different directions), have the ability to detect (proximity detection) obstacles (large and small) and report the distance (real time) on a type of display (tablet or iPad). Maximum range approx. 15-25 ft. On a 180 degree plane, one transducer would look directly left and the other directly right. Part of the concept is for the sensors to detect and report the distance to the nearest target (or possibly all targets if using multiple sensors) on a display device (iPad or tablet).

In summary, the product will need to simultaneously report distance, control LED lights and a buzzer, and report data through either bluetooth or WiFi to the iPad or tablet. Run on a battery is also a must.

1. Would the PGA450-Q1 be the best ultrasonic sensor to use?

2. What would be the best processor to use with this application?

3. What ultrasonic transducers (40 hz range) would you recommend that are compatible with this sensor? Max range 15-25 ft.

4. Any other hints or help would be welcomed that may assist with making this system actually function properly.

Thank you.

-Casey-

over 8 years ago

0 Akeem Whitehead over 8 years ago

TI__Mastermind 27950 points

Hi Casey,

1. I would recommend the PGA460 instead of the PGA450. The PGA460 is superior in every aspect of performance (max single record range up to 11m instead of 7m), power consumption (offers 300uA low-power mode), size (TSSOP16 instead of TSSOP28), and cost ($1.65 instead of $2.60 at 1k units).

2. Since the PGA460 handles the bulk of ultrasonic data extraction as far as return echo time-of-flight, peak amplitude, and width, the external master controller does not need to be very powerful. Perhaps an entry level TI MSP430 MCU with UART would suffice to also help with your total power budget. Alternatively, the MSP432 devices are part of the SimpleLink microcontroller (MCU) platform, which consists of Wi-Fi®, Bluetooth® low energy, Sub-1 GHz, and host MCUs. All share a common, easy-to-use development environment with a single core software development kit (SDK) and rich tool set. Another alternative is to use the CC2640x (BLE) or CC32xx (Wi-Fi) SoC MCUs with built-in stacks for the wireless protocols.

3. The lower the resonant frequency of the transducer, the longer the detectable range, thus a 40kHz transducer is your best option. If you primarily care about long range performance (15-25ft or 5-8m), then I would recommend a mono-static open-top transducer (such as the SensComp 40LPT16 or Prowave 400PT120). If you also care about short ranging, then a bi-static open-top pair such as the Murata MA40S4S and MA40S4R is recommended. Since you plan on having ultrasonic coverage in two-directions, it would be to your benefit to use an open-top transducer with the direct-drive muxing circuit to reduce the PGA460 IC count to one for all sensors, rather than one IC per sensor. You can see an example of a transducer muxed implementation at:
e2e.ti.com/.../603257
If the system will be exposed to the outdoors, water, or dust, then I recommend a closed-top transducer (such as the SensComp 40KPT25 or Prowave 400EP250), but you will need a transformer, and not be able to use the muxing circuit.
You can find a full-listing of air-coupled transducers here:
e2e.ti.com/.../620399
I also recommend that you read through the PGA460: Everything You Need to Know for Ultrasonic ToF (Air-Coupled) E2E post at:
e2e.ti.com/.../629374

4. The PGA460 works exclusively as a slave device dedicated to ultrasonic measurements, so your external MCU would need to control the LED+buzzer, and report data through your wireless interface. The PGA450 does have an internal 8051 to handle many of these actions, but the PGA450 may be too limited for your range and power requirements.

0 Casey Pullman over 7 years ago in reply to Akeem Whitehead

Prodigy 205 points

Thank you Akeem. Extremely helpful and top notch answer!!!

-Casey-

0 Casey Pullman over 7 years ago in reply to Akeem Whitehead

Prodigy 205 points

What components would you recommend for prototyping the ultrasonic sensor/s, buzzer, LEDs, and BLE? Launchpad and boosters?
-Casey-

0 Casey Pullman over 7 years ago in reply to Akeem Whitehead

Prodigy 205 points

What components would you recommend for prototyping the ultrasonic sensor/s, buzzer, LEDs, and BLE? Launchpad and boosters?
-Casey-

0 Akeem Whitehead over 7 years ago in reply to Casey Pullman

TI__Mastermind 27950 points

Hi Casey,

The PGA460's EVM is formatted as a LaunchPad+BoosterPack combination specifically for this add-on type of evaluation.

The Grove Starter Kit BoosterPack contains buzzers and LEDs:
www.seeedstudio.com/Grove-Starter-Kit-for-LaunchPad-p-2178.html

I've gone as far as stacking the Kentec LCD-QVGA BoosterPack on top on top of the MSP430F5529 LP and BOOSTXL-PGA460 for displaying results without the need for a laptop/GUI. In addition, I am working on stacking a SD Card BoosterPack and CC2650 BLE BoosterPack to save the results locally onto external non-volatile memory when running the PGA460 from a battery supply, and also enable the option to configure and/or readout data wirelessly over BLE. This LP-BP combo will eventually be stacked four BoosterPacks high!

Since the BOOSTXL-PGA460 is compatible with most LaunchPads, you are not limited to the MSP4305F5529. The F5529LP is only required when you want to run the PGA460Q1 EVM GUI. Perhaps a SimpleLink MCU LP would be more suitable for your application.

0 Casey Pullman over 7 years ago in reply to Akeem Whitehead

Prodigy 205 points

Thank you Akeem...I believe I'm getting close. For prototype could I:

1. Use the SimpleLink MSP432P401R Launchpad Development Kit
2. Connect two (2) SensComp 40KPT25 ultrasonic sensors
3. Connect any common type buzzer
4. Connect NeoPixel Ring - 16 x 5050 RGB LED with Integrated Drivers
5. Stack a Kentec LCD-QVGA BoosterPack
5. And then stack BOOSTXL-PGA460
6. Run on battery pack

Is this possible or would I even have enough pins? Breakout board? I can prototype the BLE later, but right now I need to drive at least 2 ultrasonic sensors, RGB LEDs, a buzzer, run on battery pack, and display the ultrasonic sensor distance....all simultaneously.

Thank you in advance...
-Casey-

0 Akeem Whitehead over 7 years ago in reply to Casey Pullman

TI__Mastermind 27950 points

Casey,
That combination seems feasible. If you are considering a SimpleLink MCU, then you can use the Sensor and Actuator Plugin for SimpleLink™ MCU SDKs (www.ti.com/.../SIMPLELINK-SDK-SENSOR-ACTUATOR-PLUGIN), which includes support for the BOOSTXL-PGA460.

Keep in mind that the BOOSTXL-PGA460's daughtercard is designed to drive only one transducer at a time. If you intended on driving two transducers simultaneously, you will need to wire the transducers in parallel. You will not be able to determine if the object is approach from the left or right, unless you use a muxing solution to drive the transducers independently using a single PGA460. (e2e.ti.com/.../603257).
Alternatively, you can use two BOOSTXL-PGA460 for independent control of each device and transducer.

The 40KPT25 transducer has a very narrow/focused beam pattern. This transducer is exclusively ideal for front-facing long ranging (no side lobe reflections). If you are trying to a detect objects in a wider range, you may need to consider a different transducer with a wider beam angle (FOV). You can find a full listing of transducer's and the beam angle specification at: e2e.ti.com/.../620399

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PGA450-Q1: Ultrasonic System Assistance