Electric Vehicle C

[dragonfruit35]

That was how it was phrased last year. Look at 2c and 2d, it is clear that as long as voltage <=9, any number of batteries can be used

Oh, I see. You meant the part about more than one battery in the propulsion circuit. That is legal, the problem is there wouldn't be enough voltage to power both.

Yes there certainly would. Voltage is the same in a parallel circuit

Never mind, I meant something else. Thanks so much for all the help!

jasonwu- I used a laser pointer on my EV (although this was at an invitational) and brought the labeling that was on the package, and it was fine. If they don't have a label, the ES might not allow them, so I would recommend you buy one from a store (mine came from Walmart in the office supply section).

[dragonfruit35]

Sorry to double post, but we have a *slight* problem. Every time we run our program, the motor doesn't even get up to the full speed defined in the program before it simply cuts off, and we can't figure out why. Can anyone help us?

edit: and also regionals is tomorrow sooo...

[Sean_Sylvester1]

Sorry to double post, but we have a *slight* problem. Every time we run our program, the motor doesn't even get up to the full speed defined in the program before it simply cuts off, and we can't figure out why. Can anyone help us?

edit: and also regionals is tomorrow sooo...

If it's not too late, what are the motor specs and what is your power source?

[windu34]

Sorry to double post, but we have a *slight* problem. Every time we run our program, the motor doesn't even get up to the full speed defined in the program before it simply cuts off, and we can't figure out why. Can anyone help us?

edit: and also regionals is tomorrow sooo...

Problems I have experienced that it could be the cause of:
1.) Arduino and motor powered by same source, voltage drops when motor is turned on, voltage to Arduino drops below 7V and Arduino and program reset
2.) Battery source insufficient
3.) You determined the speed you wanted under no load. When actually moving the vehuicle, the motor is under load thus rpm decreases

[azkbisfb]

Sorry to double post, but we have a *slight* problem. Every time we run our program, the motor doesn't even get up to the full speed defined in the program before it simply cuts off, and we can't figure out why. Can anyone help us?

edit: and also regionals is tomorrow sooo...

One thing we found out last year is that some of the traditional motor drivers that are used with the Arduino (such as the motor shields based on the L293D chipset, with Darlington transistors) would experience an increased voltage drop at higher motor currents and the car would behave exactly as you suggest (that's with a single 6x1.2V AA battery pack powering both modules). We ended up buying a discrete-mosfet-based driver (one of the Pololu high power modules), and never had any more problems. Hope that helps, belatedly...

[parasaurolophus]

Hey guys! So the way we plan to turn the car requires us to use a screwdriver to turn a screw to adjust the wheels on the car during our 8 minutes after we find out the distance.

We interpret the rules as allowing this, does anyone see any reason it wouldn't be? Idk how else you could adjust your car for different distances besides using a program, and that's not required to be able to turn the car between cans.

Thanks everyone!

[windu34]

Hey guys! So the way we plan to turn the car requires us to use a screwdriver to turn a screw to adjust the wheels on the car during our 8 minutes after we find out the distance.

We interpret the rules as allowing this, does anyone see any reason it wouldn't be? Idk how else you could adjust your car for different distances besides using a program, and that's not required to be able to turn the car between cans.

Thanks everyone!

That method is totally fine and legal

[parasaurolophus]

That method is totally fine and legal

I am very glad to hear! Although doesn't change the fact that ours still needs extensive testing and adjustment and hope It's not incredibly reliable yet. We will see how it goes, thank you so much!

[kevonz31]

So sorry to double post, but I need some advice. Because of the rules, we have to use one battery for both the Arduino and the motor shield. The *slight* problem is that the wires leading to the DC jack for the Arduino burned up when we plugged in the battery. Does anyone have any ideas?

First off, I'm pretty certain that the Arduino does not need to be powered by the same supply of the motor. Wasn't that the rule from last year that they changed?
Anyhow I power everything from a single battery pack by connecting the Arduino DC jack and the Motor/ESC power input in parallel with each other with respect to the battery without any problem by utilizing a voltage converter between the power source and the Arduino DC jack. I step up the 7.2V to 9V going into the Arduino and current is limited to <2A automatically by the regulator

If the Arduino and the motor do not have to be powered by same supply, does the combined voltage of the two batteries have to equal 9V, or can you use 9V batteries for both Arduino and motor separately?

[kevonz31]

So sorry to double post, but I need some advice. Because of the rules, we have to use one battery for both the Arduino and the motor shield. The *slight* problem is that the wires leading to the DC jack for the Arduino burned up when we plugged in the battery. Does anyone have any ideas?

First off, I'm pretty certain that the Arduino does not need to be powered by the same supply of the motor. Wasn't that the rule from last year that they changed?
Anyhow I power everything from a single battery pack by connecting the Arduino DC jack and the Motor/ESC power input in parallel with each other with respect to the battery without any problem by utilizing a voltage converter between the power source and the Arduino DC jack. I step up the 7.2V to 9V going into the Arduino and current is limited to <2A automatically by the regulator

If the Arduino and the motor do not have to be powered by same supply, does the combined voltage of the two batteries have to equal 9V, or can you use 9V batteries for both Arduino and motor separately?