motor controller for electric bike project

[LASH]

I saw some electric bike projects on the internet and almost every one have used a pre made motor controllers by paying around $40. Why can't we make our own dc motor controller some how..(as an example)we can create simple PWM input with a arduino or something then we can use maybe one or two transistors to drive the motor with that PWM signl...can someone explain why is it not possible ,what are the problems we gonna face.. and give any other suggestions if have.. thnx

 

[Bluejets]

Certainly possible if you have the expertise to firstly design the controller, secondly the expertise to build a proto-type, thirdly the expertise to fault find and diagnose any problems one might find with the design.
Then you will need to have the expertise to choose the right devices, design and build printed circuit boards and then have pockets deep enough to allow all the above and produce an end item.
That's when $40 seems a steal.
You have to remember this when you see a product for a certain price, all the above would have been done and the mass production ( maybe millions of units) brings the price down to $40.
An individual one-off attempt can never compete with this.

 

[LASH]

Thanks for the explain..But can you explain me what is the big duty of this motor controllers..If they operate using PWM why can't we get the same results with a arduino and heavy duty transistor..or we can use a arduino motor controller shield.I saw this shields can operate 13A peak..please consider that i am a newbie to the world..

 

[Bluejets]

One can.
However to even begin, you will have to find what loading and what switching elements to use ( you will find mosfets preferred)
Then using PWM you will need a driver for the mosfets.
Then a circuit board of some description.
Then Arduino of sufficient size, input sensors or switching or pots ( clone Arduino would keep the cost down there)
Then you will need to do the programming.

 

[LASH]

okay now have some idea..Thank you

 

[BobK]

Since a bike is not driven backwards, you need only a single switching transistor (MOSFET) and something to generate a PWM signal. A NE555 timer is the simplest.

Bob

 

[LASH]

Since a bike is not driven backwards, you need only a single switching transistor (MOSFET) and something to generate a PWM signal. A NE555 timer is the simplest.

Bob

thnk you

 

[Alec_t]

.I saw this shields can operate 13A peak.

I expect you'll need more than that for an electric bike.