Bill of Materials for EV

VansBuilders
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Bill of Materials for EV

Post by VansBuilders » November 11th, 2016, 7:59 am

I have been reading through EV forum discussions heavily. I have raspberry pi 2B.
But I see most of the discussions indicate that Arduino is the way go.
So I am going to try Arduino based vehicle. Based on my understanding, the following is the core list of things I need to start:

Arduino UNO board
Servo motors (2 or 4 - not sure of this)
Banebot wheels -4
Encoder ( optical or rotary - not sure of this)

Can someone provide feedback on what make/ model for servo & encoder?
What else am I missing to start?
I have resistors, breadboard and connecting wires from my Raspberry pi kit.
Thanks.

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Re: Bill of Materials for EV

Post by Bazinga+ » November 11th, 2016, 9:21 am

I believe optical encoder is the way to go (what I've been using). Also you don't need servo motors, only one single motor either brushed or brushless (I recommend brushed if you have little experience with programming microcontrollers). If you end up going with brushed you will need a motor shield which are pretty standard. For motor I would recommend a Traxxas low turn motor, and for encoder a optical quadrature encoder with at least 300 turns per revolution. You will also need gears between your motor and drive axle (I recommend a 1:5 or 1:10 gearing ratio).
You will not need a breadboard of you use the servo shield since the motor can be plugged straight into it as can the quadrature and any other electronics you decide to use. Good luck!

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Re: Bill of Materials for EV

Post by VansBuilders » November 19th, 2016, 8:09 am

Thanks for feedback. What about continuous rotation servos? I see strong recommendation for that in Arduino books for projects like this based on speed and precision required here.
Please share your thoughts.

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Re: Bill of Materials for EV

Post by Bazinga+ » November 19th, 2016, 9:06 am

VansBuilders wrote:Thanks for feedback. What about continuous rotation servos? I see strong recommendation for that in Arduino books for projects like this based on speed and precision required here.
Please share your thoughts.
Those are way too slow for what you are trying to do. Of course you could do some gearing up, but then they will be too weak and become less accurate.

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Re: Bill of Materials for EV

Post by VansBuilders » November 20th, 2016, 12:12 pm

Hi, My friend found this motor available in robotshop.com.
Micro 6V 160RPM 120:1 DC Geared Motor w/ Encoder
Product Code : RB-Dfr-668

The cost is very reasonable -$7.99
Is this a good starting point with Banebot 2 7/8" wheels?
Thanks.

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Re: Bill of Materials for EV

Post by Bazinga+ » November 20th, 2016, 2:50 pm

VansBuilders wrote:Hi, My friend found this motor available in robotshop.com.
Micro 6V 160RPM 120:1 DC Geared Motor w/ Encoder
Product Code : RB-Dfr-668

The cost is very reasonable -$7.99
Is this a good starting point with Banebot 2 7/8" wheels?
Thanks.
160 rpm is very slow. With those wheels you would be going at about 30 cm/sec so your total time would be like 24 seconds. I would recommend a counting system separate from the motor, like having a motor and then a separate encoder.

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Re: Bill of Materials for EV

Post by bernard » November 26th, 2016, 3:15 pm

Servocity has many deals this Cyber Monday: https://www.servocity.com/cyber-monday. Pair them with your Science Olympiad 25% off discount code for additional savings.
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Re: Bill of Materials for EV

Post by laidlawe18 » November 27th, 2016, 6:15 am

I'm also trying to choose what to buy based on very little experience. What do you guys think of this combo?

https://hobbyking.com/en_us/hobbyking-x ... 000kv.html
https://hobbyking.com/en_us/hobbykingr- ... rless.html

4000KV seems really fast but it seems like it would have enough torque to power the vehicle. I have virtually no experience so any input is greatly appreciated.

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Re: Bill of Materials for EV

Post by Bazinga+ » November 27th, 2016, 8:19 am

laidlawe18 wrote:I'm also trying to choose what to buy based on very little experience. What do you guys think of this combo?

https://hobbyking.com/en_us/hobbyking-x ... 000kv.html
https://hobbyking.com/en_us/hobbykingr- ... rless.html

4000KV seems really fast but it seems like it would have enough torque to power the vehicle. I have virtually no experience so any input is greatly appreciated.
If you lack torque you could always decreade your gear ratio. However, I would advise against using a brushless motor since it's harder to use than a DC motor, and this year that .5-1 second advantage between the different setups means very little.

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Re: Bill of Materials for EV

Post by windu34 » November 27th, 2016, 10:16 am

laidlawe18 wrote:I'm also trying to choose what to buy based on very little experience. What do you guys think of this combo?

https://hobbyking.com/en_us/hobbyking-x ... 000kv.html
https://hobbyking.com/en_us/hobbykingr- ... rless.html

4000KV seems really fast but it seems like it would have enough torque to power the vehicle. I have virtually no experience so any input is greatly appreciated.
Looks like a pretty good setup. I have a 3600 kV brushless motor so I wouldn't say 4000 is too powerful. Whether you use brushed or brushless doesn't matter a whole lot - I'm using brushless just because I did last year and I'm well acquainted with it.

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