Arduino randomly resetting itself during operation

Hi guys. For the past five months, I’ve been hardly working on the ultimate competition RC. It’s a nitro-based car using an Arduino for control. I use the HC-05 bluetooth module and command the car using my phone, which turned out to be useful enough for the horsepower the engine develops. The system uses an Arduino Nano powered by a rechargeable 9v battery, which also powers the two servos and the bluetooth module.

The last remaining problem is that the Arduino randomly resets itself when using the car. When the engine is stopped, this never happens, but when the engine is on, it randomly stops operating the servos and resets itself. This frequently happens when going forward, causing the throttle servo to get stuck in the open position, and the car keeps charging forward until the Arduino Nano reboots. Note that this doesn’t always happen when applying throttle. So far, I was lucky enough that the engine stopped itself due to the irregular “spasms” of the throttle servo as the Arduino reboots, but I don’t want to wait until it goes astray for good. I thought of getting a 2.5v supercapacitor connected to the Arduino to keep the voltage up. Would this fix the problem?

(deleted)

spycatcher2k:
Try a 1000uF capacitor across the 5V and GND on the arduino.

Will try on Monday. Thanks!

Hi,

The system uses an Arduino Nano powered by a rechargeable 9v battery, which also powers the two servos and the bluetooth module

  • How big is the 9V battery?
  • What voltage are the servos rated at?
  • Where do they get their power from?
  • What rating are the servos, link to specs/data?
  • What do the servos operate?

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

You project is showing classic symptoms of not enough current for all your devices.

Servos alone pull more than 1A each,.
Servos if needed to hold their position against a spring loaded or returning force will continue to draw considerable current.

Have you measured your battery volts while the fault occurs?

Thanks.. Tom.. :slight_smile:

Hi, Tom. Thanks for your implication!

TomGeorge:
How big is the 9V battery?

It's one of those common rechargeable 250 mAh 9V block.

TomGeorge:
What voltage are the servos rated at?
Where do they get their power from?
What rating are the servos, link to specs/data?

Both are Vigor VS-2 servos. They have an operating voltage of 4.8-6 volts.
You can check the specs here:

TomGeorge:
What do the servos operate?

The throttle servo operates the engine's throttle lever. It's so light, it literally dangles about when it's not connected to the servo's arm.

The steering servo controls the front steering wheels. They're made out of plastic, so they ain't too heavy.

TomGeorge:
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Sure thing: Imgur: The magic of the Internet

TomGeorge:
Have you measured your battery volts while the fault occurs?

I couldn't really, since I was rather freaked out by the engine revving like hell.

It never happened before, and I was using exactly the same devices and servos. Could a capacitor keep the power up for the Arduino during a potential power loss? Thanks.

P.S. In the sketch I didn't connect the HC-05 to the Arduino other than the 5v and the GND, since I reckon they're not affecting the voltage.

Hi,
Forget about that battery, not big enough.
You need to measure some voltages.

The throttle arm is probably pretty free when the engine is not running, but if you advance the throttle while the engine is running there probably will be a back force.

Unless you have power steering there will be forces coming back from the steering mechanism too.

You need a much bigger battery.

Can you post a picture of your project so we can see your component layout.

A hand drawn circuit with labels on pins would have been better, fritzy pictures are just that, pictures they very rarely show all the information needed.

For example are you really using a protoboard?

Thanks.. Tom... :slight_smile: