EC meter make Arduino 5V drops to 3 ish V

Other Hardware Sensors
1

I've bought this EC meter ec meter - DFR0300 - Gravity: Analog Electrical Conductivity Sensor - DFRobot.

I have water temperature, EC, PH, ambient temperature sensor and a 20x4 LCD attached to the Arduino. When I check this morning, the EC meter dropped the whole Arduino Mega Vcc to 3 ish Volts and make it hangs.

I thought all the sensors are drawing too much current from the Arduino and decides to detach all sensors except the EC sensor. But same thing happens. (note: the LCD is still attached but with external power)

Does it indicate a faulty sensor board? What can I do to debug in this case.

Thanks!

2

wmfairuz:
I've bought this EC meter https://www.dfrobot.com/product-1123.html.

I have water temperature, EC, PH, ambient temperature sensor and a 20x4 LCD attached to the Arduino. When I check this morning, the EC meter dropped the whole Arduino Mega Vcc to 3 ish Volts and make it hangs.

I thought all the sensors are drawing too much current from the Arduino and decides to detach all sensors except the EC sensor. But same thing happens. (note: the LCD is still attached but with external power)

Does it indicate a faulty sensor board? What can I do to debug in this case.

Thanks!

You failed to mention the power supply for your project. Why are you powering the sensors from the Arduino?

Paul

3

Such sensors ought to take very little power (e.g. the DS18B20 sensor that is included in that EC kit is routinely powered directly off the Arduino, no-one questions that). No specs for the sensor board, but it shouldn't take more than a few mA, and in the linked page it's suggested to wire that to the Arduino directly as well.

This sounds like either wrong wiring or indeed a faulty sensor, drawing way more power than it should, in which case you can likely find some rather hot bits on your sensor board.

4

The Arduino is powered by a 12V (2A) power source through the DC jack.

I got suggestion to not to use this DC jack. So, instead I use a USB brick charger (1A).

Arduino now doesn't hangs anymore but the voltage drop is still there. Right now it drops to around 4V (and one of the chip on the sensor board is hot)

I think I can safely assume the sensor board is fried.

Put that aside, what are the safety precautions I can take to avoid this mishap in the future? (the sensor is a bit pricy so want to avoid frying the next one)

Thanks

6

As long as you connect it as indicated (in this case: to the 5V and GND pins of the Arduino), and you don't have issues with static electricity in your home, you should be perfectly safe and no special precautions need to be taken - unless clearly stated by the manufacturer.