URM37 v3.2 Ultrasonic sensors freeze after 7-8 hours and does not recover...- DFRobot Forum

2012-09-29 00:01:21 Hi,

I have testing using different Arduino UNO boards or even breadboard version... same thing still happens...

I managed to capture some oscilloscope screenshot for your reference in Passive PWM Mode...

I've two sensors, this is the screenshot then it is working and another one when it is not working

When sensor is working :- Distance = 190cm

When sensor is not working :- Distance = 1136cm constantly... does not response to any changes to the range sensor...

When the sensor is not detecting the range, there is a delay between the trigger pulse to the PWM response whereas the working sensor, it immediately give our the PWM width according to the range it detected...

When it cannot detect the range, any power cycle/reset does not restore the it to a working state...

Yellow is the trigger pin with delay(1)
Blue is the measurement from the PWM pin

I'm using power supply of 12V SMPS 5A and not taking power from the USB port to isolate any power related issues...

stanley

2012-09-27 20:36:12 Hi,

We just finished the testing for the PWM mode of the URM37. It works fine. And we've tested it for almost 12 hours.The sensor won't freeze/hang.

This time we use the Arduino official Uno Rev2 as the microcontroller. Here's the code.
[code]#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

int URPWM=3;
int URTRIG=2;

int val=0;
unsigned int Distance=0;
uint8_t EnPwmCmd[4]={
0x44,0x02,0xbb,0x01};

void setup()
{
Serial.begin(9600);

lcd.begin(16, 2); // init lcd
lcd.setCursor(0,0);
pinMode(URTRIG,OUTPUT);
digitalWrite(URTRIG,HIGH);
pinMode(URPWM, INPUT);
for(int i=0;i<4;i++) Serial.write(EnPwmCmd[i]); // set the URM sensor to the PWM mode
}

void loop()
{
lcd.clear(); // clear the display characters
digitalWrite(URTRIG, LOW); // Trigger the sensor
//delay(1);
digitalWrite(URTRIG, HIGH);

unsigned long DistanceMeasured=pulseIn(URPWM,LOW); // Attach the distance feedback from the URM37
if(DistanceMeasured>=50000) Serial.print("Invalid");
else Distance=DistanceMeasured/50; // calculate distance value (unit: cm)

val=Distance;

lcd.setCursor(0,1);
lcd.print(val); // Display the distance value

Serial.print("Distance=");
Serial.print(Distance);
Serial.println("cm");
delay(200);
}
[/code]

I think there's also 3 ways you could try.

1. Change a new microcontroller
2. Try the sample code I posted
3. Try to drive the module directly via the USB by using the USB to TTL converter. Then test the module directly with your Computer serial to avoid the problems caused by other device.
4. The worse way for me to solve the problem that the sensor freeze is that use a relay or MOSFET to control the power supply for the sensor. If the sensor freeze, directly disable the power supply and restart it again. Lauren

2012-09-27 09:33:26 Here are the equipments I used :-

h/w : Arduino UNO R2
s/w : Arduino IDE 1.0.1
power supply : 12V 5A SMPS into Arduino UNO

I tested the voltage on the 5V on UNO and it reads 4.95V

I have tried both the Passive PWM mode and also the TTL mode... same results, it just stop working after 6-7 hours on both the units...

What other tests can I run to solve this issue ?

Any suggestions on what test can I run when the URM37 freezes/hang ?

I have an oscilloscope that I can read the data from the pins...

Thanks

I've attached a picture of the UNO, LCD on breadboard and URM37 ...
The first line on the LCD is the distance in cm, second line is the number of times the loop is executed... stanley

2012-09-27 02:44:44 [quote="stanley"]
I'm using Arduino Uno rev2 with Arduino IDE s/w 1.0.1

The power supply is from the USB port from the Arduino UNO...

I did plug in an oscilloscope and found that when it is not working, it is still sending out pulses of 50ms (invalid readings) all the time...

Thanks
[/quote]

Hello Stanley,

We have tested the sensor. The result and platform we made is described below.

Arduino IDE: V1.01
Controller: Arduino official diecimila... a really old board...Haha...we'll exchange a new controller for later testing
Hareware interface: TTL of URM37
Display monitor: LCD 1602 shield for displaying the measuring distance
Code: Using the library released on the DFRobot website
Power supply: 7.5v external AC-DC Adapter

The system has kept running for more than 24 hours. And it runs properly.I have uploaded the picture of the system.
We'll keep test the sensor by using the pwm interface.
Hope you will post more information about your system or more testing results to figure out the problems together!

;)

Lauren

2012-09-25 07:59:23 [quote="stanley"]
[quote="Ricky"]
[quote="stanley"]
I'm using Arduino Uno rev2 with Arduino IDE s/w 1.0.1

The power supply is from the USB port from the Arduino UNO...

I did plug in an oscilloscope and found that when it is not working, it is still sending out pulses of 50ms (invalid readings) all the time...

Thanks
[/quote]

it looks like that your sensor were working fine. Double check your arduino code, especially the memory and error handling.
[/quote]

How can the sensor be working fine when it is not reporting the distance but gives out 50ms (invalid readings)..

I'm using the exact code from the examples on PWM passive mode on [url=https://www.dfrobot.com/wiki/index.php?title=URM37_V3.2_Ultrasonic_Sensor_(SKU:SEN0001)]https://www.dfrobot.com/wiki/index.php?title=URM37_V3.2_Ultrasonic_Sensor_(SKU:SEN0001)[/url]
[/quote]

Sorry, misreading. Lauren will build a system trying to duplicate your problem. R2D2C3PO

2012-09-25 07:47:37 [quote="Ricky"]
[quote="stanley"]
I'm using Arduino Uno rev2 with Arduino IDE s/w 1.0.1

The power supply is from the USB port from the Arduino UNO...

I did plug in an oscilloscope and found that when it is not working, it is still sending out pulses of 50ms (invalid readings) all the time...

Thanks
[/quote]

it looks like that your sensor were working fine. Double check your arduino code, especially the memory and error handling.
[/quote]

How can the sensor be working fine when it is not reporting the distance but gives out 50ms (invalid readings)..

I'm using the exact code from the examples on PWM passive mode on [url=https://www.dfrobot.com/wiki/index.php?title=URM37_V3.2_Ultrasonic_Sensor_(SKU:SEN0001)]https://www.dfrobot.com/wiki/index.php?title=URM37_V3.2_Ultrasonic_Sensor_(SKU:SEN0001)[/url]
stanley

2012-09-25 06:40:30 [quote="stanley"]
I'm using Arduino Uno rev2 with Arduino IDE s/w 1.0.1

The power supply is from the USB port from the Arduino UNO...

I did plug in an oscilloscope and found that when it is not working, it is still sending out pulses of 50ms (invalid readings) all the time...

Thanks
[/quote]

it looks like that your sensor were working fine. Double check your arduino code, especially the memory and error handling. R2D2C3PO

2012-09-25 06:09:11 I'm using Arduino Uno rev2 with Arduino IDE s/w 1.0.1

The power supply is from the USB port from the Arduino UNO...

I did plug in an oscilloscope and found that when it is not working, it is still sending out pulses of 50ms (invalid readings) all the time...

Thanks stanley

2012-09-24 23:41:20 Hi Stanley,

We will test the URM37 with the Arduino and power adapter for 10 hours to figure out the problems.
On the other hand, could you please describe a little about the power supply and the microcontroller used?

;) Lauren

2012-09-24 05:50:03 I had 2 units of URM37 v3.2 and after running it for 7-8 hours without issues, it just stop working randomly... even after I reset the sensors a few times, it is still not working...

The only way to get it working again is to turn it off for like 2-3 hours, then it is working again...

Looks like some sort of "charge/capacitance" still in the URM37 and once the "charge/capacitance" is discharged, it started working again..

Can someone suggest on how to fix this issue as I m using the URM37 on a 24hours basis for a people sensors...

I've tried both PWM mode and serial mode, but still faces the same issues... this happens to both my URM37 sensors..

Thank you stanley