Issue with 9v battery to vin and same used to run dc diaphragm pump using relay

Projects General Guidance
1

I'm building a simple oil dispenser using Arduino Uno . I need to run the pump ( pin D10 to signal 5v relay which connects the diaphragm pump powered using 9v battery )for specific time when I press the button(D8 pin).
It works fine when I power up Arduino using usb but the program does not run when I use the 9v battery to power up Arduino through vin and also the diaphragm pump.
Need your help to know what went wrong

2

Normal 9 volt batteries don't usually supply enough current.

Better off with a pack of AA.

3

Thanks , if I need to use aa batteries, then I have to use 6 of them to power the dc pump .. do you have any alternatives on how to power up both the pump and Arduino.

4

It all depends on the individual application

I tend to use the 18650 batteries or similar rechargeable packs myself.

5

Thanks,, will try with rechargeable batteries

6

Get a pump that runs well on 3.7V.

Then you can use a single LiPo to power both the Arduino (get a 3.3V Pro Mini) and the pump, without wasting power on voltage converters.

7

@ballscrewbob... Powered the board and pump with seperate 9v batteries and the project works fine . But I need to know whether there are any other issue with using the same power supply to board and to power up the pump. ?

8

@wvmarle .. thanks for the tip.. it would be cost effective to work with a single lipo cell.. and also do I need to use relay to power up the pump or is there any way to directly power the pump through pro mini board ?

9

That method simply adds some extra current and there is no problem using that method.
However you will most likely find that the pump starts to fail quite quickly as it draws that current from the battery.

Still you will be better off with a different battery situation from the regular 9V batteries.

10

Either a RELAY or a MOSFET would be a preferable method to switch the pump itself as the Arduino can only supply a very small amount of current which is part of your ongoing issues.

11

Got it .. will experiment with those

12

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