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angusgr

2,866 karma · joined September 23, 2008

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angusgr··on The motor turns too much
Hi janosch,

Appreciate the heads-up from someone who has been there before! Like you I was a bit surprised by how much the integration bled across subsystems. I like the egg analogy.

> isolate the inverter and motor and make them believe they are still in the original vehicle by replaying CAN messages, ZombieVerter is a project with that approach

For sure, great tips. This is what I've been working towards - at the time of that post I was spoofing the minimum number of CAN messages (still quite a lot), but in the months since I've been gradually replacing modules with spoofed signals by reversing them one at a time. Some of the follow-up blog posts have details about this.

I'm approaching the point of only needing the original motor stack (inverter, charger, etc), the original BMS, and all other modules spoofed out via CAN messages and a few discrete wired signals. The OEM BMS might turn out to be too hard to re-integrate once the battery pack gets split apart, but can cross that bridge when I come to it.

More blog posts (and open hardware & software) to come, I hope!

angusgr··on The motor turns too much
If you're interested then click the link in my first reply (which is to a newer post). The first video shows the working car reaching 8000rpm (about 80km/h) around six seconds after the accelerator was released. The second video shows the speed creeping steadily from 38km/h to 44km/h (~2600rpm) after switching to Neutral (before we got nervous again and touched the brake).

(I don't really understand it, but I also haven't managed to think of a safety issue here for normal car use: the broken driveshaft is just a bit scary as the motor spins unloaded at >10,000rpm for a while. The only other time this seems likely to happen is if a mechanic puts the car in Drive on a hoist, and it'll stop as soon as they tap the brake.)

angusgr··on The motor turns too much
> I think you were emulating the ABS module right? In that case, the spinning out of control is actually probably your fault. If you had not emulated this, the system would realise there is an ABS fault (from the messages not being present) and not use the ABS reported speed. It might even fall back to motor speed automatically.

That's a reasonable expectation, and this got left out of the follow-up post I linked, but in the "full car with wheels off the ground" tests we actually tried unplugging the brake module of an otherwise working car and it didn't change anything (including the gradual constant rpm increase in Neutral). If anything the behaviour might have gotten a little more aggressive with the brake module missing.

Have now observed similar behaviour for all three of "spoofed brake messages with 0 wheel speeds and emulated checksums", "fully operational car with wheels off the ground", and "car with wheels off the ground and ABS/brake module unplugged". ¯\_(ツ)_/¯

> Re: shaft scenario, if the motor shaft is broken the safety risk is pretty minimal because the torque wont actually cause the car to move. > > I guess this is what they arrived to in the FMEA.

Fair enough, that makes sense. I guess if that's the case then the other behaviour is outside of the scope of what they need to care about.

angusgr··on The motor turns too much
> So wheel speed sensors drop out and the car will accelerate uncontrollably?

No, I don't think any of my bench tests suggest that for this car. The torque is minimal throughout, so if the motor was pushing an actual car then it might not move at all. If it did move, even a light touch on the (mechanical) brake pedal would stop it.

My problem is that I had a bench setup with no load on the motor and no mechanical brake. I could have pulled the safety interlock (all EVs have these for emergency first responders) but this stops the motor at all costs - wasn't sure of potential damage to the motor controller circuitry from back EMF.

angusgr··on The motor turns too much
Hey! Post author here.

I appreciate the insight from someone who's worked on this kind of thing formally, thanks.

> Most likely what’s happening is that the creep torque is applying a constant small torque and the wheel sensors are reading 0 continuously, so it continues to apply a constant small torque.

This was also my hypothesis at the time of the post. Turned out it's less constrained than this, a fully operational car with the drive wheels off the ground will also run away to high rpm (even in Neutral): https://www.projectgus.com/2024/04/unremarkable/#on-car-test...

There's still minimal torque, as you say, so a small press on the car's brake pedal is all it takes to stop. However I think if a driveshaft broke on a real car then it'd be spinning fast for a minute or two... It kind of makes sense that the control loop is tuned for a heavy car with a fixed drive ratio, though.

I am still hopeful there will be a way to stop this behaviour via a control signal (rather than pulling the safety interlock and slamming the contactors open). Have left the problem aside until I have a mechanical brake to use for testing! If that doesn't work out then it's still usable I think, provided any EV conversion is single speed fixed gear just like the Kona.

If you have any other insights on this then I'd be very interested to hear them, though.

angusgr··on Anatomy of a cheap USB-to-Ethernet adapter
(Blog author here)

You're spot on about the PLL stage, a few people on Reddit pointed the same thing out when I first posted it. Makes sense, although I still think it's interesting they added it internally to an otherwise (apparently) cloned design.

You're also right that USB CDC does provide the option for a generic USB Ethernet device, however this silicon is ASIX-specific (not just the USB IDs.) ASIX's Windows drivers include their own system driver binaries, and the ASIX Linux driver has a lot of ASIX-specific stuff in it.

I think it's kind of possible ASIX made this themselves as some kind of no-name branded unadvertised market segmentation effort. I can't understand what their rationale would be exactly but hardware companies do unusual things sometimes...

angusgr··on Tiny $45 cubic mini-PC runs Android and Linux
I haven't tried any of their other products, but the iMX6 has a very large detailed technical manual (publicly available, not under NDA) and their Linux kernel trees are updated in public via git (presumably not everything is public but it's a lot more transparent than the occasional tarball source drop approach), plus they have people involved in yocto development. Better than many/most of the ARM SoC manufacturers.

The only undocumented/secret squirrel business AFAIK is the Vivante GPU. And that's universal across ARM Soc GPUs, sadly.

angusgr··on Tiny $45 cubic mini-PC runs Android and Linux
Freescale i.MX6 is a really nice platform. Shame it hasn't gotten broader traction, I think because it is moderately more expensive than its competition.

Since May I've been using an imx6 based gk802 ($70 quad core "Android TV" stick) as a personal server (email, RSS, VPN, etc.) Has worked really nicely considering. (Blog post about installing debian on it: http://projectgus.com/2013/05/debian-installer-for-zealz-gk8... )

angusgr··on Sony Smartwatch now open-sourced
I expanded this comment into a blog post, and corrected some of the factual errors in the comment: http://projectgus.com/2013/06/sonys-open-source-smartwatch/
angusgr··on Sony Smartwatch now open-sourced
On the optimistic front, with a bit more digging I found this comment from Jerker Lindgren Götsten (Sony Mobile): http://developer.sonymobile.com/2013/06/13/were-opening-up-s...

"The article was just a first step towards opening up the SmartWatch, more details will follow as the project progress."

So maybe it's not the last gasp...

angusgr··on Sony Smartwatch now open-sourced
Rather than "open sourced" all I see is "a bit open specced". Yes, the "hacker guide" has details of what chips are on the board, and how they are connected: http://developer.sonymobile.com/services/open-smartwatch-pro... ... and there's a separate page with a guide to putting it in DFU mode to upload a firmware.

Which is cool, but the chip names could have been found by the people who'd already done teardowns and the pinouts could be found by buzzing one out (possibly sacrificially by removing chips.)

The chip datasheets they link were all all already publically available, the Cypress touch sensor one is even a link to alldatasheet.com(!)

Probably the biggest letdown is the Bluetooth/FM chip made by Sony, arguably the most useful and most complex device aside from the MCU. That link is to Sony's marketing specs page with a block diagram and not much technical info that I can see. I can't find any information about the chip made available to the public by Sony.

Ironically enough there is a longer 6 page Sony datasheet leaked on datasheet sites, but even this doesn't have pinouts or begin to explain how the SPI interface to Bluetooth/FM functionality actually works.

I think it's good that a major company like Sony released even this small amount of information, although it's worth noting that reverse engineers have found more information on similar products acting entirely by themselves (take for instance the PS3 Move controller: http://eissq.com/ps3_move/ )

On the other hand I think it's very bad that most people will glance at this and see Sony "open sourcing" something when they appear to be open sourcing nearly nothing. The RTOS they used is probably proprietary property of a third party so they can't open source that, but they could release their application source code for the smartwatch - allowing people to see how they communicate with the Bluetooth/FM chip, for instance. That kind of source could be ported to an open source RTOS.

The optimist in me hopes that detailed technical information will be forthcoming over time, but the pessimist in me thinks this is the feel-good last gasp of an end-of-life product. :/

angusgr··on Ask HN: Ticket tracking systems?
(Last time this came up was here, I think, but nearly 3 years ago: https://news.ycombinator.com/item?id=1331626 )
angusgr··on Flickr gets new UI, new Android app, 1 TB free space
I agree anyone seriously wanting to host that many photos will not want to split accounts, but FWIW statistics (current Pro feature) don't seem to be offered at all any more.
angusgr··on Poll: Do you have a 3d printer?
A number of things - the Z axis seems loose, the other axes skip steps (possibly the stepper drivers overheating), general issues with bed adhesion and warping.

All common 3d printer issues, though some are exacerbated because I bought a cheap kit from an unknown supplier. I got to a point where every time I fixed I problem I'd notice two other ones, and put it down and haven't picked it back up.

Good advice for people getting 3d printers is to decide if you want a printer as a tool for design/prototyping, or 3d printing as a hobby. I told myself I wanted the second as a path to the first, but after many hours of printer building I concluded that I really just wanted the first.

angusgr··on Poll: Do you have a 3d printer?
Selected Yes, but I really meant "I have one and it doesn't work properly, haven't touched it in months and wondering if I should get rid of it." :/
angusgr··on Poll: Do you have a 3d printer?
Is there a Hackerspace near you?

http://hackerspaces.org/wiki/List_of_Hacker_Spaces

(If there's not one nearby, you could always start one... when I cofounded a hackerspace I met a lot more than 15 new people who wanted to share 3d printers and the like!)

angusgr··on #ifihadglass I would jailbreak it and modify the software
Google disabled access to /proc/config, which makes the process of building a vaguely compatible kernel all the more like guess-and-check.

Is there really no .config in their GPL release? AFAIK compile-time config is a GPLv2 requirement as part of the "scripts used to control compilation" (Gpl-Violations FAQ specifically mentions Linux .config files.) I'd hope there's either a .config or a defconfig that applies to Glass as-shipped.

(NB: I don't mean to dispute your overall point by this, just wondering.)

angusgr··on Circuits.io is growing up – multi-layered PCBs and more
FWIW I have access to an Eagle license but prefer to use Kicad whenever I can. In no small part because of the Linux app being clunky (also because Kicad is FOSS.)

The annoying thing about using both is they're both similar-but-different in lots of little ways (like the other comment says, all EDA apps are weird.) Learning one once you're used to the other is a pain, but it's not impossible.

angusgr··on More than 500,000 Google Reader users have joined Feedly in the past 48 hours
Ah, right, thank you. I hadn't realised they weren't importing, just accessing.

I'm not a feedly user so I don't mind but thanks for the link to the suggestion, good to see it's being considered.

angusgr··on More than 500,000 Google Reader users have joined Feedly in the past 48 hours
As far as I can tell Feedly has no OPML export feature, so if it eventually goes away it's a dead end for users.

(Please prove me wrong, but I searched the site and also installed the extension to try and find one.)

angusgr··on Review: Google Nexus 4 Android Smartphone by LG
Ah, that is a very good review. Thanks. Maybe the parent meant to link to it, too. :)
angusgr··on Review: Google Nexus 4 Android Smartphone by LG
I went and reread it, because I'd skipped the Nexus 10 section last week.

At least the article describes the author's experience of holding the phone, if not actually using it.

But I didn't feel my two questions were answered. The only part that came close as the Google person saying that LTE increases battery usage. I want to know more than just what the manufacturer says about it, ideally based on some hands-on experience. Which is what I at least appreciated about the Wired review.

I do agree the article is better than the video, but it's still mostly just repeating what Google said on launch day.

angusgr··on Review: Google Nexus 4 Android Smartphone by LG
I thought the suggestion was more that by producing just one variant for all markets/regions/carriers, Google/LG can leverage economies of scale to bring the overall price down.

I haven't looked at the S3, but past Samsung models have had a bunch of variants marketed under the one model name.

(How much this really factors into the pricing, I doubt if we or Wired can really know.)

angusgr··on Review: Google Nexus 4 Android Smartphone by LG
I totally agree that the Wired review wasn't all that it could have been. It did answer some of my basic questions though (like 'how does the battery life hold up?' and 'is it a lemon or not?')

I can't really say the same for the Verge video, though. It felt to me like Google's PR video, made by a third party. The only even vaguely critical question was "so it's like Swype?" IIRC the interviewer doesn't even get to hold the phone. Surely tech journalism can do better.

angusgr··on The PC isn't dead
A few weeks ago I would have largely agreed with the post, but recently I had a bubble-bursting experience.

I'm currently in the middle of running an "Arduino for Beginners" workshop series at our local hackerspace. We have 25 attendees, 24 of them are brand new to the hackerspace. All the attendees are technically literate and interested, but only one or two are programmers or heavily into technology. Everyone brings their own laptop.

The first hour of the first session was almost entirely spent with everyone setting up their laptop with the Arduino software. At least 3 of the attendees took closer to two hours, both with weird Windows problems and driver issues and random slowdowns, unexpected software alerts, etc. One took more than the workshop's 3 hours to get running smoothly, her laptop finally deciding it needed to install many dozen security updates.

All four of the people whose Windows computers caused them such slowdowns told me "I barely ever turn this on any more, I just use my iPad/tablet and phone at home."

This is purely anecdotal and it's a small sample size, could easily be non-representative. But it did make me think, if I wasn't a geek and a hobby programmer/tinkerer then I'd pretty much just do email & web browsing at home, occasionally update/print my resume or write a small flyer. Would I need a PC? Why would I bother to own one, especially if PC maintenance was of no interest to me?

angusgr··on New Arduino released: the 32bit Due
Weird. FWIW I'm on 22.0.1229.94 Ubuntu 12.10 (161065) and it rendered fine.
angusgr··on Vimium: Vim Keyboard Shortcuts for Google Chrome
Just for what it's worth in case anyone's considering not trying Vimium on this basis, you can disable Vimium for selected sites by clicking on the V logo next to the navigation bar.

Also FWIW, but I find Vimium convenient just for j, k, J, K, G & gg on most sites. :)

angusgr··on Entertainment Weekly puts smartphone in 1000 magazines
I hope someone works out who is obliged to provide GPL Linux source code (CW network? Entertainment Weekly?), so they can run their own OS on their throwaway adphone.

Has to be something they can be made into that's more useful than scrap.

angusgr··on The lightbulb reinvented
Have you ever worked with X10? It's a standard finalised in 1975, and this shows.

Take a look under "Commands getting lost", "Relatively slow", "Limited functionality", "Interference and lack of encryption" for a quick overview: https://en.wikipedia.org/wiki/X10_(industry_standard)#Limita...

Certainly there are good things about having a standard for home automation, but there are many good reasons for not adopting X10.

(I take heart in the fact this project has some committed hacker types involved with it, Andy Gelme was a founder of the Melbourne hackerspace and I absolutely believe the Kickstarter project when it says the device will have a specified API and be hackable. Not an open standard, but at least interopable.)

angusgr··on The lightbulb reinvented
I'd be generally more worried about the power supply components. There's a tiny switchmode supply in there, which means capacitors. Which would be my main concern for early failures, I'd think far earlier than the LED under normal conditions.

Hopefully they'll be able to arrange good quality caps for manufacturing, even better if the whole unit can be opened up and serviced. Although it's questionable whether 99.5% of the market would ever try and fix it.

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