CAN controller/monitor for the Gen II Prius

I've read through a handful of threads where some guys are making devices/writing software to interface with the CAN. Last month I figured I'd give it a try too. For me, understanding the CAN specifics and decoding the messages has been difficult but fun. Anyone who says that they understood the CAN network protocol and decoded the CAN messages for the Prius easily is smarter than I am. Nevertheless, I pushed through, sometimes staying up until 2 or 3am trying to get everything working. I guess part of my problem was writing the USB code too but life isn't easy either.

I'm not sure what the end product will be. I don't even know what this thing is fully capable of but the past few days of testing have been really interesting. I've attached a screenshot and as you can see the layout is still in its infancy. I seem to change it daily to improve the look. Using visual gauges seems like a great approach because a quick scan of the screen will reveal something awry. I'm also including numerical values for more in depth investigating. My traction/braking gauge will turn green when in traction and red when in braking and I'm planning to change all of the gauges to include color changes. For example, if the battery temperature increases past 105 degrees, it will turn from blue to red so when the screen is viewed, it will catch your eye.

I had three interfaces but canned one. The graphical LCD screen didn't seem like it was worthwhile so I stopped writing the code for it. I currently am writing the code for a 4X20 LCD screen and a USB 2.0 VB program that interfaces with the microcontroller. I can get about 30 readings a second but when I datalog the information it's more like 5 times a second. I'm still working on that to get it to a point where I'm comfortable with it.

So many ideas have come from my experimenting but what I'm interested in is what you (the person reading this post) are interested in. My end goal is to sell a functional product so if you could design this tool the way you wanted to, what would you be most interested in? I'm pretty sure I can read just about any CAN message and controlling some things shouldn't be a problem either. I'm probably about 40% through what my original intention was when I first started so I'll know a lot more over the next couple of weeks.

I could also make simple devices with no visual aids. My mind is still churning but these things are certainly within my capability: A plug-n-play HV battery fan controller or plug-n-play EV mode controller/feed back module are just two of the things I'm looking to produce. Maybe even a plug-n-play engine temperature spoofer and all of these for a low cost. Even the USB version with data logging should be around $100.

Again, if you wanted to buy a CAN controller/monitor for your Prius, what would you want on it?

 

This wasn't intended to improve MPG's, although I can't rule it out. My original intent was for this device to be more of a troubleshooting device. Having "something" improve your MPG's by 5 MPG is difficult to achieve. I've found that driver habit is the biggest contributor to low MPG's on a daily basis. Without trying, I can get 52 MPG. If I really concentrate on all of the little things, I can get 59 MPG on the same route to work.

Agreed. The laptop wasn't really used to be a driving screen and before the user enters it they must acknowledge a pop-up screen with a disclaimer on it.

I'm not sure how to achieve this. IMO, you would need to start at the same SOC, same battery temp, same environmental conditions, etc. each day you descend down the hill. As an example, you'll regen more with a lower SOC and normal battery temp then you would with a battery that is 105 degrees and an SOC at 72%.

You can log data and as of now only the laptop can be used to do that. I'm thinking about including an SD card or using the internal memory of the processor but I haven't looked at the write speed of either, which may slow it down, but the issue here is that adding stuff like this isn't like going to the store to buy a gallon of milk. It's going to take some time to see if adding these features are worth it.

I haven't looked at that signal yet. The gauge is just sitting idle on the screen for now until I get to it.

Done. In the snapshot below, I've added virtual buttons to do just that. You just simply enter your CAN data packet to the right of the TX label, the press the "PGM" (program - circled in red) button and then press the "SD" (send data - circled in black) button. The data will come back in the RX field or be routed directly to one of the virtual gauges, if the gauge is on the screen. There's a lot of "behind the scenes" tasks that are being done but if the user wants something specific, they can enter the appropriate code and request it. I may make this a one-step process in the future but that's how it works for now.

I want to make a database so the user won't need to enter the CAN code, they'll just have to know what they want. I'll probably leave that feature there in end because I'm sure they'll be things a user wants to see that I wouldn't have thought about during the design process.

I don't know anything about the KWP. Can you send me or point me to some information on it? I can take a look to see if this can be incorporated in my design.

Not sure what you mean? Do you want my device to talk to the ELM?

I've added the battery block voltages and resistance readings, along with shifter position and some other small items. Still plugging away to make this a very user friendly tool with a lot of features. My ultimate goal is to make this somewhat of a tech stream tool that doesn't cost thousands of dollars. I'm still looking at a price point of under $100. The automatic fan controller works awesome and I will sell that as a plug-and-play unit for a lower price if someone doesn't want/need this program below. My battery temp never gets above 100 and I don't have to do anything to maintain that temperature. It will also warm up the battery automatically when it's cold as well.

 

I'll give it my best shot but I would probably need the Techstream to accomplish that.

Coke and Pepsi exist. Toyota and Honda exist. McDonalds and Burger King exist. Each one has something different to offer.

 

Did you want the Jacuzzi in the roof of the car or in the back seat?

I'm a novice programmer (I'm much better with hardware/designing circuit boards) so some things are a little harder than others. I actually started doing an iPad app, which I know will work, but the hardware that you need to connect to the iPad is slower and it's costly. I'm thinking about doing this with WiFi because pretty much every device has it nowadays. Being a single dad and having my kids full time, it's hard to find time to keep things moving but I take a couple of hours every night to make some progress.

I like what I have right now and I will post a YouTube video tomorrow so you can see how it works. I'm not a car guy and I doubt I have all of the signals that people would want to view. In my post tomorrow I'll ask you guys what else you would like included, how you want things arranged on the screen, what kind of buttons/interfaces you would want.

As far as the KWP, I've looked into it briefly but I need more time. Can you buy that ELM device as just an IC? If so, worst case scenario is that I put the IC on my circuit board. When I get more time I will look into it with a lot of detail and hopefully I can get it working. Regarding the Techstream (reading inf files/bleeding the brakes), it's a long shot but I'll try my best.

I don't think this is reinventing the wheel here. I can design an interface for each specific person. For the person who wants a plug-and-play device that is customized to what they want, this will work for them, especially if they don't know any programming languages. I'm trying to make this as cheap as possible and since most people have a laptop, I figured this would be the best approach but as it stands now, these are the GUI interfaces I'm attempting to have it compatible with:

1. Laptop -Done
2. 4x40 OLED screen -Done (Next weekend I will mount this in my car so you can see what it looks like installed)
3. 4x40 LCD screen - Done
4. iPad - I'm able to communicate but it will take a lot more time before this is completed.
5. Android/iPod - haven't attempted it yet.

 

That's perfect! Thanks for the link. The IC's are little pricey but as a worst case scenario it's not a bad option. I will definitely include the KWP in my device.

 

2009Prius - Which IC do you use? Only one IC mentions KWP specifically.

 

I can communicate without wires now and see the data on the internet but it's a LOS 2-way system that is hosted by an embedded web server - Definitely not something that is user friendly.

Regarding Wifi, yes, it would be able to connect but the issue is writing the GUI's for all of the devices. That would mean all of the USB work I've done up to this point is wasted. I will get to that point but I want to have a fully working/user friendly product first and then I can add the WiFi feature when I have time. I'll make the circuit board so that the end product won't have to be a redesign but rather just drop the WiFi module in, reprogram the IC and it's done.

 

Yes, all of the USB 2.0 work is completed. I'm just adding variables, colors, gauges, etc. and making sure my math is correct for each new variable. This is what's slowing me down. Getting time inside the Prius to verify the signals can be difficult.

 

I don't know much about the Techstream but does the Techstream do that the mini vci cannot?