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I would like to connect two sensors to Arduino Mega, but I don't how to connect the pins. My two sensors have 0-5V Signals, each with a positive and minus cable. Should I connect the positive cable to each A-X pin of arduino (e.g. A0 and A1) and connect both negative cables to the same Arduino GND pin?

Would this way mix analoge and digital GND? I read that both should be kept separated. How to achieve this.

UPDATE:

Sensor Specification: http://www.optris.com/optris-ctlaser-3m

Outputs / analog: 0-5/10 V

Output impedances: mV min. 100 kΩ load impedance

Power supply: 8-36 V DC Current draw: max. 160 mA

Hangon
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  • What type of sensor are you using? Are there other cables involved (VCC)? How is this sensor using power? If you are using a temperature sensor, such as a thermistor, you'll need a circuit instead of a direct connect. – Mepix Aug 21 '17 at 21:09
  • @Mepix thank you for your comment. I edited the question with info about the sensor. Im powering the sensors with 24V from an AC/DC converter. – Hangon Aug 21 '17 at 21:41
  • Be careful though with connecting the sensors to the 5V port of the mega. The voltage regulators usually can handle small currents only. Some sensors have LEDs on them or other components that draw relatively big currents. If you put to many on the 5V of the arduino you may brake it. If this is the case you will have to use a separate voltage supply for your sensors. – Anteino Dec 02 '19 at 21:02
  • This question is off-topic because it is not within the scope of questions appropriate for this site, as defined in [What topics can I ask about here?](/help/on-topic) Please also see: [What types of questions should I avoid asking?](/help/dont-ask) You may be able to get help on [another Stack Exchange site](//stackexchange.com/sites#name), *perhaps* [electronics.se]. However, be sure to *read the site's on-topic page prior to posting*. – Makyen Feb 23 '20 at 19:46

3 Answers3

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Your general configuration is correct. You can connect the 0-5V output from the sensor to the Analog In on the Arduino Mega. This link has a diagram that shows the best pins to use for the Analog vs. Digital Ground. Use the pins that are near the label "analog ground".

Arduino Mega with Digital and Analog Ground Labelled

As a side note, there appears to be some discussion on how "good" the internal separation is between analog and digital ground on the Arduino Board in the forums (here and here). All the grounds are connected on the Arduino board. You seem to be using a high quality sensor and other boards or ADCs may be more suitable for your needs. Try it, look at the quality of the signal, and make a determination if your signal suits your needs. For most applications, you should be OK.

Mepix
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  • thank you for the explanation. You mentioned that I should maybe use other boards or ADCs. I bought the ADC MCP3208 with 8 channels and 12 bits resolution. I would like to use it's pseudo differential mode, where channel 0 is for IN+ and channel 1 is IN - (ch2 IN+, ch3 IN- and so on) http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf Should the sensors and the ADC share the same ground using the AGND pin from ADC? – Hangon Aug 22 '17 at 19:09
  • Yes, they should have a common ground. I mentioned the other boards in case the Arduino signal wasn't clean enough for you. (I'd expect it'll be good enough for most cases.). Hook it up, look at the signal with an oscilloscope, and then determine if the signal is clean enough for your needs. – Mepix Aug 23 '17 at 02:46
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you can use common ground line for all the sensors which saves your ground pins

Ishanka Nirmal
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First of all you have to have an idea about the sensor and what kind of output you expect from your sensor. There are digital and analog pins in arduino board. if you're expecting analog output it would be better if you use A0-A15 pins. If you're expecting digital so you can use 1-53 pins.

for every sensor there are power pins and IO pins. in power pins there are plus and minus pins. Plus wire should connect into 5V/3V (according to the sensor) and your minus pin should grounded into GND. be careful when connecting plus pin because some sensors can't work with 5V. you have two power options in your arduino board. (3.3V and 5V).

When connection plus and minus pins it would be better if you use breadboard. because there are only few power and GND pins are available on board. you can use common power lines and ground lines.

for your question there is no any issues mixing ground or power lines together. The only thing you have to keep separate is your IO pins.

Malith Ileperuma
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