Thread: PaulF's 2002 Volvo S60 version 3 - the half watt system

I'm happy that there are other forum members interested in micro controllers. I had expected there wouldn't be much interest around this thread!

Originally Posted by malcom2073

That's pretty awesome stuff. I especially like how you routed your programmer wires through the power plug hole in the Mega Pro I am actually embarking on a similar project, but using a small RF transceiver rather than a cell modem so I can communicate with my car when I'm within a couple hundred feet. Probably going to be using just a regular Arduino Uno since I have one laying around. Ultra Low power consumption ftw

Thanks! Those holes are too big to go unused haha and I didn't trust those solder joints being swung around.

Some of the modules in the 900mhz band claim miles of range. I've never actually experimented with RF stuff, but if I was in the suburbs with less buildings this would be a pretty sweet option to avoid the cell bill. Now you've got me thinking about doing something hybrid so I can still talk to the car when I'm in a no service area...

Originally Posted by tripzero

I use the hall sensor one for higher current things like what's going into my second battery when it charges. I'm using smaller current sensors (also from sparkfun) for the lower current stuff like the solar panel.

Originally Posted by malcom2073

One thing that I know tripzero did with his car, and I know I'm going to do with mine, is set it up with current sensors (sparkfun has some hall effect ones, not cheap though) to measure the solar panel and car computer. This would allow you to keep track of how much power you are using for your system. Not really especially useful, but another cool piece of information to know

I want this too. A problem with many on sparkfun is that they're also AC only. I was considering using a shunt based one for the arduino stuff... but really if I keep this below 100mA I don't care enough about what it's using. On the other hand, it would be interesting to tap my alternator, main battery, and accessory batteries, and see what power is coming from where when the sound system is cranking, but with the hall sensors, that is too damn expensive.

Originally Posted by tripzero

That relay board looks quite awesome. I may have to check it out.

Originally Posted by malcom2073

Really nice relay board. I use the ULN2308A darlington drivers for switching relays all the time. I never even thought about trying amazon for things like relay boards though, that's a really good deal. Usually I just go for futurlec.com, but they take 3-4 weeks for shipping since it comes from china, and you always have to check the boards for build quality :/.

I never thought about amazon either, but I was searching for serial modems and I eyeballed that board in the related results and wanted to kill myself after having soldered all those other relays. They also have 8 relay versions. The screw terminals are extremely convenient too.

Originally Posted by tripzero

Very awesome! I lost my fusion brain... so I'm trying to think up a good reason to use the arduino (prolly a smaller one like the uno).

Thanks! Do your always on stuff with it! There's just no winning with full heavy-weight operating systems.

Originally Posted by that_kid

Great project. I would love to see a LTE modem but I doubt we'll see one anytime soon.

Thanks! I don't see why you couldn't have a 4g LTE modem. I'm intentionally avoiding internet connectivity for cost/power/reliability concerns. I used to have an always on computer in the car with 3g, but that was too expensive and too unreliable. Serial really doesn't have the necessary throughput for 4g speeds though, and a microcontroller doesn't have the processing power to pump 20+mbps of data haha. You could always just stick a rooted android phone in the car. Write some slick apps to control a microcontroller and host wifi etc. Also, you could get really crazy and get an AT&T (they support GSM and LTE as far as I know) sim card and then implement something to switch the sim between the GSM modem and a USB lte modem for the computer I think sim card A/B switches actually do exist. There are also USB host shields for the arduino which theoretically let you talk to USB modems. Unfortunately I had a pretty rough time getting that to work and opted for the most direct/reliable solution - serial.

Originally Posted by that_kid

I'm going to check out that GPS you posted. I already have a USB GPS installed but having one that I can share with my on board Arduino would be nice.

The thing looks pretty awesome. I'm thinking that with an FTDI usb-serial converter might actually be one of the best GPS options available for a car pc. Won't know until I try it out though.

Originally Posted by tripzero

Ahh, so version 2.0 got scrapped? What kind of issues did you run into with the pandaboard? I imagine you could get it under 5W. Also, I'm willing to bet the Atom consumes more than 8W...

Well I still have the FitPC in there and manually turn it on/off nightly. I had stability issues all around with the PandaBoard because of the lackluster proprietary-ish omap4 drivers. Both linaro and ubuntu run great for a few minutes then eventually become unusable. Most of the issues stem from graphics. I messed with it a ton in the summer, but it's gotten quite a bit better so I tried again in January and was still disappointed. I'm not saying it couldn't work, but it is far more buggy than I would want to mess with in the car. Sadly by the time this is 90% stable, something better will exist. Either way, the definitive solution is the arduino, and once that's done, I won't need to strive for low power in the car.

Originally Posted by tripzero

How much did your 30W solar panel produce? I've already seen mine generating 350mA of current. That may be enough to power the ARM board during the day. I may use the arduino control the power of the PC and have it shut off at night and possibly during certain hours of the day when I'm unlikely to be using the car.

I tested it outside of the car on the first day I owned it. Laid it on my driveway on a reasonable day. Produced ~1.2 amps. I've honestly never measured it again. I think part of the problem may be that we're dumping the power into agm batteries. That kinetic battery I see in your trunk is AGM, right? I believe I read somewhere that solar charge controllers kill them if not designed for AGM, and I can attest to the fact that my Optima blue top's life is SIGNIFICANTLY reduced - like my stuff only lasts a few hours on it before the battery reads 6 volts, but that may be because of several significant unnoticed discharges. Might want to ping OldSpark on this one since he seems to be the most knowledgeable about battery tech on this forum.

I tested it outside of the car on the first day I owned it. Laid it on my driveway on a reasonable day. Produced ~1.2 amps. I've honestly never measured it again. I think part of the problem may be that we're dumping the power into agm batteries. That kinetic battery I see in your trunk is AGM, right? I believe I read somewhere that solar charge controllers kill them if not designed for AGM, and I can attest to the fact that my Optima blue top's life is SIGNIFICANTLY reduced - like my stuff only lasts a few hours on it before the battery reads 6 volts, but that may be because of several significant unnoticed discharges. Might want to ping OldSpark on this one since he seems to be the most knowledgeable about battery tech on this forum.

My battery is completely dead at 10.5 volts. Anything lower than that will damage the battery. I just emailed the company who made my solar charge controller to make sure they support AGM batteries. I'll find out soon if I'm destroying yet another battery (this is my 3rd). AGM is typical for solar applications so I hope it supports it.

There isn't any information about battery types on the spec pdf: http://lib.store.yahoo.net/lib/wind-sun/SunGuard.pdf

I've recently heard not so great reviews of the pandaboard. I wonder if there are some issues with it. My biggest issue has been usb-related (talking with the dcdc-usb on ARM) specifically. I haven't messed with the graphics enough to know how stable that is...

Originally Posted by tripzero

My battery is completely dead at 10.5 volts. Anything lower than that will damage the battery. I just emailed the company who made my solar charge controller to make sure they support AGM batteries. I'll find out soon if I'm destroying yet another battery (this is my 3rd). AGM is typical for solar applications so I hope it supports it.

Mine is dead at 10.5 volts too. You never want to bring an AGM even that low. Let alone 6 volts. MY battery is VERY damaged haha.

Originally Posted by tripzero

I've recently heard not so great reviews of the pandaboard. I wonder if there are some issues with it. My biggest issue has been usb-related (talking with the dcdc-usb on ARM) specifically. I haven't messed with the graphics enough to know how stable that is...

That's really odd that you have USB issues. I was under the impression that USB support was perfect. I mean I cruise around an ssd over USB with it at around 46mb/s

For me, graphics is so bad, that the gnome decorator ends up taking on the ubuntu 8.04 desktop theme completely randomly and more and more of the gui stop working. Even without compiz.

Yeh... i never got far enough to mess with graphics much but from what I did use things seemed to generally work on the igepv2. 8.04? That's pretty old...

I was able to get sgx drivers up on the igep and get the qt-qml examples working.

Technical support at kinetic was who told me 10.5 was as low as I could go. I have the dcdc-usb defaulting to 11.2 volt before it shuts offs the power. I may keep it at that threshold.

Originally Posted by tripzero

Yeh... i never got far enough to mess with graphics much but from what I did use things seemed to generally work on the igepv2. 8.04? That's pretty old...

I was able to get sgx drivers up on the igep and get the qt-qml examples working.

I'm sure that if I spent enough time, I could get something working, but that's a separate project. It would be very cool to have in my car, but I drive this thing every day, and I want it to work all the time. Until I can have that confidence, it's just not happening. I mean, I was willing to sacrifice having a front end, professional GPS, etc, but if the base operating system can't run stably it's just not worth it. Also, at some point the audio server would always crash which would be a pain too. Overall my experience is just that there are too many little things wrong that add up.

I know years ago, I argued with you years ago in some thread about Windows vs Linux, but now I run linux 24/7 on servers and on my desktop. I develop on linux at work, and I've lived without Windows for two years now. In my opinion, linux belongs in the car more than Windows does, but it's just unrealistic on the these arm boards right now without a professional dev team and if I'm running an x86 box... I may as well run windows to get all the benefits of corporate software.

With this install, I may go back to a full power PC, just to take advantage of the speed. Though I have the FitPC overclocked now and it gets pretty damn good performance.

Originally Posted by tripzero

Technical support at kinetic was who told me 10.5 was as low as I could go. I have the dcdc-usb defaulting to 11.2 volt before it shuts offs the power. I may keep it at that threshold.

I'm sure you can go to 10.5, but if you're going from 13.0 to 10.5 daily, that battery won't last long. OldSpark went on an interesting rant against AGM batteries a while back which was very informative. Truly, I have better luck with my $120 sears lead acid battery than my optima. I've wrecked 3 optimas already while that thing keeps on kickin'. I'm kind of curious what I could do with a giant, cheaper SLA battery which isn't necessarily automotive and which is designed for slow discharge

Originally Posted by PaulF

I'm sure that if I spent enough time, I could get something working, but that's a separate project. It would be very cool to have in my car, but I drive this thing every day, and I want it to work all the time. Until I can have that confidence, it's just not happening. I mean, I was willing to sacrifice having a front end, professional GPS, etc, but if the base operating system can't run stably it's just not worth it. Also, at some point the audio server would always crash which would be a pain too. Overall my experience is just that there are too many little things wrong that add up.

I know years ago, I argued with you years ago in some thread about Windows vs Linux, but now I run linux 24/7 on servers and on my desktop. I develop on linux at work, and I've lived without Windows for two years now. In my opinion, linux belongs in the car more than Windows does, but it's just unrealistic on the these arm boards right now without a professional dev team and if I'm running an x86 box... I may as well run windows to get all the benefits of corporate software.

I actually agree with you. If you want to make something work with linux on ARM, you need more than one person in his spare time. That's one of the reasons why I dropped LinuxICE in favor of something like MeeGo/Mer.

btw, found OldSpark commenting about AGM batteries here: Dual Battery Help Please!

the search on this forum is crap or I'd probably be able to find more...

Yeah, I don't think that's the conversation I remember, but there is a little bit of information there. When I say "informative" I mean it will tell you everything you don't want to hear haha.

On another note, Polulu sells a bunch of hall effect current sensors, though, they're not touch-less (you need to solder to the board)
http://www.pololu.com/catalog/category/118

I got the GPS stuff in on Friday.

I'm using the Venus gps chip:
http://www.sparkfun.com/products/11058

This antenna:
http://www.sparkfun.com/products/464

I'm feeding the GPS 3.3 volts from a switching regulator.

It is connected to the computer via an FTDI usb serial converter:
http://www.sparkfun.com/products/718

It is also attached to the arduino. Note that the GPS talks 3.3 volt serial and my arduino talks 5.0 volt serial, so I only have the arduino receiving data from the GPS module, if I were to transmit to the GPS module, I would need to shift the levels down, and there is no good reason to since you only need to transmit when you configure the GPS, and I doubt I'll ever need to reconfigure it again.

The configuration software is actually pretty nice, it lets you control the exact frequency of every NMEA sentence, baud rate, etc. I have it set at 115200 baud. The attached screenshot shows me reading data through the arduino (left) and through the USB-serial converter (right). Boring picture, but "no pic, no proof" applies haha

Now I need to write the code to get data from the GPS and sensors, and box up all the hardware, and I'll be ready to stick this thing in the car.