Open Source "CA" for Arduino something to begin?

[hillzofvalp]

I want this because I don't have money for a CA, but I do have an arduino.

I want to have code I can put on an arduino and output to a basic lcd or even over wireless to smartphone. So let's build a library! I can see more useful programs being implemented such as smart current limiting (based on grade or SOC), cell gap monitoring, security features, auto lights.. etc. It's all very simple for some of us but at the same time not of personal relevance to these same individuals. So let's make it easy for those who don't know what the hell they're doing so we all can get some good functionality (which, at times, includes myself)!

I know someone was working on an iOS app but I think that fell through...

 

[MadRhino]

I see it as 'how you value your time'.
Price of Arduino + hours spent on implementing the functions of a CA + fabrication of a neat waterproof handlebar mount display, makes it too expansive for me.

 

[hillzofvalp]

It couldn't take that much time, especially if a bunch of people contribute. It has benefits for everyone.

The arduino has most of the features necessary to do what the CA does, am I wrong? should only take mostly simple resistor circuits. Honestly, who actually uses every feature on the CA? why not let people who don't have $120 but gobs of motivation and nerdiness be made capable of setting something up with a little tinkering and a $20 board? maybe for adjusting a single parameter such as current limit rather than 20 features?

Yeah there are 50% of us who don't have time to put something together, install software, upload programs and troubleshoot, but I think a good chunk of us could really benefit and have nerdastic orgasms.

all are paying $120 for the whole package but there is no watered down cheaper version. $120 could buy any of us another 100Wh! That's a lot! --much more value here

 

[dennyt]

Funny you posted this, I just ordered my first Arduino with the eventual goal of rolling my own CA. I have a CA, and it's great, but I wish a few things were different

For me this isn't about saving money, it's about learning by building something.

 

[hillzofvalp]

For me this isn't about saving money, it's about learning by building something.

What did I tell ya.. a nerd learning by building something.

Cool, I'd like corroborate and learn too, so if you're interested in bouncing code back and forth in a google doc, let me know!

By the way, my goal isn't necessarily saving money.. it's that I already have an arduino being used for things on my bike, and I don't need much more than smart current limiting functionality and SOC. I don't see much value in the current CA for average ebike use, but is a good early attempt.. They are better I think for a quick solution for a monitoring device for a larger EV, such as one of the go carts they race in the EV Grand Prix here at purdue. Those guys have to look at it all the time if they're going to make it through the race.

In my case, I can count charge cycles with my charger... and I think the ideal scenario is to check this stat directly on the charger or uploaded onto a computer or server, if even necessaery for a person to check at all. capacity drop is not something you worry about on a day to day basis.


Something I thought of today was using an IMU to detect the grade, and have automatic current adjustment. Ie, it would automatically ramp up the current limit on steeper grades (for whatever time interval)..

 

[el_walto]

I have an arduino that i have not used very much. Could be interesting, but I'm very n00b as far as programming comes into things. I almost finished programming a crappy alarm clock

I like my cycle analyst and think it's a great product.

The feature i mainly thought would be good is a Bionx type torque sensor system where i don't need to use a throttle. Unfortunately most of the work would probably go into figuring out an adaptable sensor, which i have not figured out in my brain yet.

 

[acuteaero]

Saving money is rarely a good reason to build something from scratch. "Never build what you can buy"

I would hesitate to discount the worth of the CA, I think there's a pretty good consensus that it's a well designed and high value part for an ebike. Justin has been working on it for over five years- http://www.ebikes.ca/drainbrain_history.shtml. It's a mature, reliable product that's specifically designed for ebike applications.

If you want to build a CA comparable device as a learning experience you should go for it, figuring out all the details of how a device like that should work and how will give you a lot of good experience, just don't expect it to be quick or cheap. And don't expect the ES guru corps to start writing libraries for you because you're too cheap to buy a CA and to lazy to do it yourself. If you just want CA functionality for your bike, you should save up and buy a CA.

Sorry to be a bit harsh, but I think you're approaching this with a bit the wrong attitude.

 

[hillzofvalp]

quite the contrary... I like the CA. It is feature-packed and warranted.. but I also want to see core functions made more readily available to people, and I don't want people to write libraries for me any more than I want others to ask the same of me (unless I know others are willing to contribute). It's a learning opportunity for many and makes sense for some people to pursue fewer functions, especially if only few are needed.

I also think it's a medium to design and test features that the CA doesn't have.. idea spawning for everyone, including revisions for the original CA and testing of those unworthy, seemingly dubious ideas. What about potential entrepreneurs...Maybe it would be nice to have a starting point, etc. An idea may seem pointless at first, but once one nails something down it serves as the basis for more meaningful concepts

 

[MadRhino]

Yep, it makes sense if you target functions that are not in the CA.

 

[hillzofvalp]

iOS is a whole additional platform only going to be tapped if a community of arduino and ebike tinkerers start laying the ground work

I can write some stuff for arduino interfacing, but I rather there be people corroborating so that coding style and variables are more consistent and easy to understand... and we are more productive in commenting on and revising our work. It's also more motivating for me if others are working for better overall end functionality (so time is best spent).

We can get some easy-to-follow tutorials going on the features we code, and ease off some of the hindrances of ebike innovation..

 

[gtadmin]

Just wondering, did you do a search on "arduino"?

 

[bzhwindtalker]

An arduino mini can be brougth for 3€ delivered on ebay! Im just in the process of building a RC interface with current limit and LVC based on that. I cant code a full cycle analyst programm but a lvc+current limit+RC interface is within my skillz. Im following this one, BT data logging to smartphone would be awesome to have!

 

[adrian_sm]

I would recommend the Arduino Nano over the Mini. Purely becuase it has a mini-USB port to allow programming without the need for a special cable like the Arduino Mini Pro's do. Prices on ebay aren't that different.

Reference thread for another open-source Arduino interface on ES:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=29561

Post with a good voltage & current sensor that is easy to integrate with arduino.
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=29561#p427859

Post with links to hardware and software for PID control, LCDs & SD datalogging.
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=29561&start=15#p447908

Finally I totally agree with others that it takes quite a lot of time and effort to roll your own CA (trust me ), so I would only embark on this is you are truely expanding on what the CA can do. Otherwise you would be crazy not to just buy one. And don't underestimate the challenge of mounting the LCD, and making everything water tight.

Good luck.