Servomotor and LCD overheat the arduino

Using Arduino General Electronics
1

hello everyone, i'm currently doing a project : Automatic fish dispenser. it consists of 2 servo motor controlling
a) food dispenser
b) bait

so the flow is something like this

feeder set to 2 times feeding per day, when it comes to the 1st feeding, the servomotor2 will rotate and let the bait submerge in the water for 2 minutes. if the fish pulls the bait (connected to the limit switch too) the servomotor1 will rotate and dispense the food. after two minutes, the servomotor2 will rotate lifting the bait from the water. and this repeat for another time in 6 hours.

the LDR sensor are suppose to detect the level of food in the dispenser. little food = led on.

LCD is just a display of feeding hour, no of feeding and time to next feeding.

BUT whenever i connect one servomotor and the LCD on the arduino, it overloads!
I've tried using an external power source but there's no movement at all.

can anyone tell me what went wrong here?

2

Hi mecha_ppl,
firstly DO NOT power your servos from the Arduino, this will cause lots of problems including damaging the arduino. Use a serperate power supply or batteries, BUT make sure all GNDs are connected together!

Servos use a lot of current 1A or more, so the arduino regulator can't handle this and the arduino resets itself, etc.

We really need to see your schematic and code in order to help more...

Hope it helps, Regards

Mel.

3

here is the schematic

AFF.png
AFF.png1203×489 143 KB

4

That's not a schematic.

5

boolrules:
That's not a schematic.

Well, whether it is or not, it has at least one serious issue - it shows the positive of batteries and servomotors connected to ground on the Arduino.

6

i didnt realised that. thank u for pointing it out.
is it right now?

aff1.png
aff1.png716×539 48.4 KB

7

mecha_ppl:
is it right now?

I do not know whether it is or it isn't but it is in no small part because that diagram is far worse than the first!

8

perhaps this is easier to understand?

aff2.png
aff2.png1195×472 139 KB

9

Now you have no common ground between the battery/servo side of things and the Arduino....

10

do u mean i have to connect the battery ground to the arduino ground?

11

See attached....

mecha_ppl:
do u mean i have to connect the battery ground to the arduino ground?

See attached

servo power.png

12

aaaa i see. thank u so much for your help.

best wishes

13

i've connected the batteries's ground to arduino. is this correct?

aff3.png
aff3.png1206×450 138 KB

14

Yep.

Without that, the 5V signal on the yellows from the Arduino to the servo has no reference to be measured against. It would be like trying to measure the voltage of a battery by only applying the meter's red lead to the +ve and not touching the black to the other end.

Or like the sound of one hand clapping.

15

JimboZA:
Or like the sound of one hand clapping.

Kudos!

That's the best come-back I have seen in quite a while. :grin: :grinning:

16

I have these Zenny moments....

Edit: but searching the forum, I see I didn't invent that thought and it predates my joining the forum by some years, see here.

17

Ah well, but as I see it, it really gives a feel for the problem