Max load is used by the 12 V DC Motor and MCU is going into off state

Thread Starter

mukund_bm

Joined Aug 24, 2014
7
Building the sanitizer using the 12v DC motor / Solenoid Valve, input voltage to Motor / Solenoid Valve and MCU is from the same circuit.

Whenever MCU - digital pin D7 triggered, max load is used by the Solenoid Valve / motor and MCU is going into off state, please suggest how to proceed?

1596445575256.png
 

AlbertHall

Joined Jun 4, 2014
10,245
Another drawing error: relay coil should connect to 12V, and the diode is reversed.
To fix the problem you might try a diode between 12V and C11/7805 junction. Feed the relay and solenoid direct from the 12V.
 

jpanhalt

Joined Jan 18, 2008
10,103
Of course, there may be errors in the drawing. However, if the drawing is correct, and D7 is an output that idles low, MCU should run. Setting it high creates a short to ground, which could be what shuts the MCU down.

At this point, the TS needs to submit an accurate schematic.
 

Thread Starter

mukund_bm

Joined Aug 24, 2014
7
It was my mistake, Schematic was completely wrong, below find the updated Schematic. The issue is, power to MCU and Solenoid Valve / 12 V DC Motor is from the same source, whenever the D7 is High, Solenoid Valve / 12 V DC Motor starts and MCU goes on offline state.

1596453812721.png
 

ericgibbs

Joined Jan 29, 2010
10,501
hi bm,
I would add some extra decoupling caps, say 100nF close to the power pins of the Atmega, also on the Input and Output side of the 7805 reg.
E
 

MaxHeadRoom

Joined Jul 18, 2013
21,257
Why are you using a relay to pick up a solenoid valve on the same supply?
Why not just use a logic level FET and pick up the solenoid directly?
Max.
 

Thread Starter

mukund_bm

Joined Aug 24, 2014
7
Thanks All for the responses.

I will split the power source into 2, for MCU and Solenoid Valve separately, which I believe should resolve my issue.
 

Thread Starter

mukund_bm

Joined Aug 24, 2014
7
Very true, Relay is not required. It can be achieved by using Logical FET or Optocoupler.

Thank you very much for your suggestion.
 
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