Talk me out of using a Nexus 7 as a digital dash
 

Im having really bad thoughts about attempting this.

Inspired by this thread:
https://www.miataturbo.net/megasquir...android-68849/

Im thinking about buying a 8GB Nexus 7, pulling my stock instrument cluster (which has issues) and replacing it with a Nexus 7. I had planned on running RaceChrono on an old smartphone next year, but the Nexus 7 has the horsepower to do both, so it would be a one stop solution to data logging and on-track data.

The downfalls I can see so far are:
1. Potential glare from the screen. Solution: Matte screen protector?
2. Using stock sensors. Solution?
3. Lack of fuel gauge. Solution: Find a 5-110ohm fuel gauge and/or convert it to 5v and use an analog in/out on the DIYPNP
4. Others I havent thought of yet.

This seems like a great idea on paper, so what am I missing?

How do you plan to power it?

Also you will need access to the power button to turn the screen on and off.

I've been wrestling over this intensely for a while.

I think this would work well actually. I thought about doing this and removing my double din radio. Powering it would be easy.

It does seem like an easy button, no?

Can you elaborate on how to power it? I had a few ideas, but nothing solid.

If you have an Android phone turn it off. Then turn it back on and time how long it takes to boot. Now then expect to add that the startup time of every time you start the car unless you plan on leaving the tablet on 24/7. I think having a tablet to display everything can/will be very useful, but I am not sure if they are ready to be used full time as gauge clusters.

I would think you would be able to take a power cord for one and splice it to a power source just like you would a wideband or any other accessory. The way I was going to place it I could always just use the lighter and an adaptor if splicing it would not work.

Hows the visibility in direct sunlight?

I wouldn't want one as a full time dashboard for this reason alone, in natural light they're an absolute bugger to read, and in direct sunlight virtually impossible. My SGS2 is utterly useless even on a cloudy day when outside.

Men, just leave it screen off when not in use.

My Galaxy Nexus charger is 5V, there needs to be some sort of transformer to step it down to 5V. That's an unknown at this point though.

Probably wouldn't be in direct sunlight much, if at all, especially if mounted into the stock cluster location in some form.

Why would I want to talk you out of this? It's a brilliant, epic idea.

For power, just wire in another car charger thing under the dash. Feed it power on when ignition on.

In response to the guy talking about startup times...

The Nexus 7, because it runs stock Android on a quad-core processor, starts up VERY quickly. Plus, you don't technically have to have it fully booted to drive the car... just to see your instrumentation :fawk:

Finally, in terms of sunlight, isn't that why there is an instrument binnacle? I don't think you'd have too big of a problem with this. It's also not a fair comparison with the GS2 because the GS2 uses a Super AMOLED screen which is known to be rubbish in sunlight, unlike the Nexus 7's IPS display.

I'm something of an Android geek... PLEASE PLEASE PLEASE if you do this, make a sweet write-up with lots of pics... :party:

It's not that hard to "force stop" from the app menu. Mine shows-up in the tray.

Looks like I will be making some dash measurements tonight.

I do not want to talk people out of it, I personally think it is a great idea. I just do not think it is completely ready to remove the stock gauge cluster. I think setting it up in the spot the radio goes for now while retaining the stock cluster is the way to go. Once we have figured out an easy way to show gas, and oil pressure, odometer and shadow tuner is a bit more stable switch to tablet only.

Guessing much?

You'd be surprised I think. Try resting your phone in that location during a commute and see how you get on.

First, the tablet has an IPS display, which is far less affected by sunlight in my experience as previously mentioned. I have an ASUS Transformer with the same technology, and sunlight isn't an issue.

Second, the only "commute" the car sees is on and off the trailer. The only things I really need to see in the dash are pressures, temperatures and RPM. Everything else is a bonus.

If that's the case... a track car? Then why not? Not like you're hopping in to get groceries in the thing. Sounds like fun!

I might consider it if I was using an MS3, but with a DIYPNP you're running short on analog inputs. You're going to have a hard time getting enough aux signals into the box to make a usable dash.

Correct, track only.
Yes, this issue is in the back of my mind as well.

Elaborate please.


Wife has the 7. Similar to an iPhone or iPad, screen shuts off when you tap the power button on the side of the unit. Also have to touch the button to turn the screen back on. You at least need to be able to reach it.

Not sure why you would power down completely.

-Motorola Atrix running cm7
-Ebay BT Adapter
-5hz BT gps receiver
-attached with a modified gopro tripod mount and silicone to the back of the phone
-Hardwired to car under the dash and hooked up to a small 1/2 DIN car speaker for audible alarms and music to the track

Currently setup to take OBD2 data and display it using torque and do poor mans gps lap timing using trackmaster. I find that a 5hz BT gps adapter is far more accurate than the built in. Power UP/Down is painless, as the phone will carry stand by battery for days. Glare isn't all that bad but you have to have brightness cranked up on max during the day. I'm probably going to get an anti glare screen protector to try that out. If that fails I could see making a little shrowd for it but that will cut down on fat finger access.

I'm currently working on turning this into a poor mans data collection setup. Just working on an easy way to sync up the laptime gps data with trackmaster. Data from the obd2 port is obviously collected at a lower frequency and with a slight delay. I've done a few test video's overlaying the data on a gopro vid already and it worked like a champ. Once i do a little more work I'll have a pretty decent setup considering what i spent.

https://www.miataturbo.net/attachmen...ine=1351558935

https://www.miataturbo.net/attachmen...ine=1351558935

https://www.miataturbo.net/attachmen...ine=1351558935

speaker setup
https://www.miataturbo.net/attachmen...ine=1351558935

I feel as though this appropriately describes my feelings towards your post.

https://www.youtube.com/watch?v=YXON...tailpage#t=81s

consider my mind just as blown on that link you posted to the android ms thread that ben started. I've been so consumed by the install and figuring out how to merge/sync the data... I hadn't even considered using it for ecu purposes.

So answer your original statement... "Talk me out of..." Fuck no, do it. Consider me game to exchange info/ideas when you do. :party:

None of that is an issue, it can all be controlled by software.

Another option is to use the magnetometer. Probably less of an issue in a track car, but having a case fold open/closed would help hide it from would be jack-off asshole thieves and do double duty as a power button. This is gonna be awesome.

One of my coworkers has the nexus 7. Hopefully on Friday I will drive the track car into work and get some pictures of it in different spots and such on the dash.

Yes, on the gauge cluster would be an excellent help.

I started the process of putting the DIYPNP in the car tonight, but that didnt go over so well. :rofl:
Thread here:
DIYPNP no start on a 92 Miata - Miata Turbo Forum - It's the Cat's Meow

You guys are killing me.. We're really trying to figure out how to power a tablet in your car???

https://www.miataturbo.net/attachmen...ine=1351772959

Uh, I am. I don't exactly have a cigarette lighter or much of a dash anymore. Hell, most of the factory wiring is gone, and stuff like the radio, cool suit etc get their power from a distribution block that's wired right off the master kill switch.

So yes, I am thinking a little outside the box on how to power it.:rofl:

https://www.miataturbo.net/attachmen...ine=1351773691

Or take the USB Cigar adapter, disassemble it, place internals into a smaller case and rig up your own connection method. Your car has +12v in it somewhere.. Use it somehow to power the adapter.

Battery drain
 

You may have issues with charging. A standard USB charges at 500mA, which may not be enough if you're pulling multiple data plus GPS. 700mA would be better, as long as it turned off when the car was off.

While not as sexy, the b&w kindle nook and similar items are completely sunlight legible, and since they're Android-based they can be cracked.

okay, so maybe I've thought of this too...:)

Your points are valid, but here was what I determined:

Charging: Not as big of an issue, only has to run 30 minutes to cover a TT or race. Can charge outside the car after that.

Kindle/Nook: Probably disqualified, Im not sure they have the horsepower to run BOTH the Shadow Dash and the RaceChrono. Maybe if you were only using one or the other it would be feasible, I dont know.

Really, for powering the unit, just use one of the above suggestions, or get a 5V voltage regulator and solder up an adapter harness wired into the ignition. Mount the regulator to something large and metallic that will sink the heat. It's not that hard. Stepping down DC voltage is cheap and easy.

5V Fixed-Voltage Regulator 7805 : Voltage Regulators | RadioShack.com

I think an Android tablet connected to a Bluetooth ODB-II adapters running torque and racechrono might work in the track car (LS1 with a GM ecu). Interesting idea.

The Chinese lighter adapters are 2.1A or even higher now.
1A are all over the place (ordered 10 for $15 a couple of days ago).

You'll have to jumper the data pins on most chargers, otherwise the device thinks it's connected to a computer and will only pull 450mA. New-er Android devices measure the resistance across the two data pins to determine if it is connected to an AC charger or a computer to enable the appropriate charging mode. There are 4 pins, connect the middle two and you have an "AC" charger and the device will pull however many amps the charger provides.

I think its a great idea, but be aware that digital RPM gauges in general are harder to follow from the corner of your eye than analog gauges.

Back when I raced motorcycles I put a digital dash on my race bike and hated it. I couldn't read the tac without looking directly at it, which is not something you want to do.

I bought a reconditioned 7" Galaxy tablet for this very purpose; bluetooth, GPS, wifi, big screen, accelerometer, etceteras. I was talking with the guys at the Braille booth last weekend and they brought up the charging issue. Prior to that it hadn't crossed my mind that if the unit was plugged in to a USB it would still run out of juice.

I'm using a simple ELM327 bluetooth device ($30 on Ebay) that connects to the OBDII and sends data to the Galaxy. There are several applications, including "Torque", that give you a user-selected gauge panel array.

Edit--the higher-power chargers are a mixed blessing. If there is no circuitry to cause a float charge, your nice lithium ion battery could overheat and explode. Not good.

So I thought most or just about all of the modern devices that use li-ion batteries had the charge regulation intelligence built into the device itself (not the charger) and therefore the 5VDC charger feed could be a dumb 5V non-current regulated signal. Not true?

Honestly dunno. I would hope so, but you know what they say about ASSuming...:)

Confirmed, no current regulation required. I talked to a buddy of mine that develops chargers for cell phones and what nots, including the N7. Just get a 5V regulator and wire it in. The battery charging controllers are in the device, not in the charger. Like midpack mentioned above you may need to jumper the connector to keep it from limiting current to 450mA.

For example, here is a 2A car charger for a N7.
Car Charger for Google Nexus 7

ASSuming cuts both ways. I would be pissed if a N7 needlessly died in the middle of a track session because I was not feeding it enough power.

Mission Motors use a 7" Android tablet for their dash on their crazy quick electric motorcycle. When Jay Leno took it out, the dash turned off or something.

I'm pretty sure they're using a Galaxy Tab. They have a really nice cnc machined holder for it when I saw the bike at the MotoGP. It sure would be nice to have that holder...

A challenger appears

Race Capture Pro - Data That Drives You | Indiegogo

Doesnt have a super pimpy dash, but it does tick a lot of the checkboxes that I was after. Having dedicated sensors for stuff is a great perk that I had considered passing on with the DIYPNP.

Edit: They are also planning a Bluetooth based interface. Hmmm...

Brent and crew at AutoSport Labs are good folks (and the NW Region SCCA Solo Sponsorer).

^^ Good to know.

Two of us here in Texas are seriously looking at the Race Capture Pro setup; we very well might pull the trigger. BTW they are working on a dash board setup that will use an Android tablet like the Nexus 7 and plug into their system. This is potentially very, very cool.

I just bought a Nexus 7 to play around with. It's really nice. Trackmaster is about 25% larger on the screen compared to a Galaxy SII, but does not fill the whole screen. I talked to Jeff at Trackmaster and asked if he could make it larger for the Nexus 7. He said he would put it on his to-do list.

Two problems. Temperature range on a tablet is commercial temp range not automotive/MIL. Phones and tablets auto shutdown at high temps that are easy to reach in a car. I also don't like a huge li cell in front of my face consistently exceeding its temp range as thermal runaway is no fun.

The second issue is gauge response time. OBD II is slow for one channel. Start logging a whole dash worth and the gauge response is notched at best and very poor compared to any standalone gauge. Newer high speed OBD II standards negate this but only for some 2004 or newer cars with capable readers.

My buddies Speed 3 runs on can bus and Torque runs a full screen of gauges in almost real time.

A full Android tablet based TunerStudio program for Megasquirt is what I'm waiting for and then I'll be looking into this further. TunerStudio/MP3/Pandora compatible head set. Awesome.

You sound like a huge pussy.

Well, that's a surprise.

Two solutions:

1. Stop being a pussy. Everything on the car is used outside of its engineering envelope. Id be much more concerned about hub failures and ball joint shearing.

2. Reading: Its fundamental.

How is the view from your padded room? Air a little stale maybe? :rofl:

Here--go cheap or go home gauge panel
 

Kindle Paperwhite $118

Android based, viewable in direct sunlight, viewable at night with backlit screen.

jailbreak: Jailbreaking the Kindle Paperwhite

add a wifi OBDII reader from Ebay for $27:

ELM327 WiFi OBD2 OBDII Wireless Car Diagnostic Reader Scanner Adapter for iPhone | eBay

Download Torque or whatever other OBDII Android software you can find. If you're sneaky, you might even be able to integrate a tethered GPS module.

Duct tape it to your dash, you cheap bastard. :)

Some say that he needs a tugboat to tug his wiener. And that if the water is deep enough it takes two tugboats. All we know is, he's called The Hustler.

Yeah, so the point is that many tablets stop working at automotive temps rendering them useless which makes the idea dumb for many situations. As in just park your car on a hot summer day in the south, come back 1 hour later and the display will be dead for an extended period of time not an oddball situation.

OBDII makes for a shit gauge cluster when passing multiple inputs over the old standard again rendering the gauge shit.

Nobody else brought up these relevant points either because they didn't know or were living in the wonderful world of delusion.

Some tablets are ok with higher temps and some cars do have high speed interfaces. In those specific cases, this is a great idea just do your homework. Otherwise it is like the wad of feces spewing from your face when you try to speak.

wouldn't worry about heat
 

I wouldn't worry about heat unless your tablet was in direct sunlight...a shade is a must, or removal when not in use is a good idea. It would also be easy to mount the tablet so air could circulate behind it.

OBDII is another matter. There are high and low speed channels for OBDII, and older models don't have as much bandwidth as newer vehicles. Certainly data that's not time critical would be fine--oil and water temp, voltage, manifold pressure, etceteras. I'm not aware of any off the shelf programs that would allow you to choose the OBDII data rates per selected data, 1Hz for low level data and 10/100Hz for rpm, speed, etceteras.

However, a tablet could be set up for all the secondary (low data rate) gauges, while a nice big Autometer with shift light could show the important stuff.

Apparently you missed the part where this is a race only car.

Remember kids, reading is fundamental.
Apparently you missed the part where this isnt happening over OBD-II.

Remember again kids, reading is fundamental.
Thats because everyone else can read and comprehend at something more than a kindergarten level.
Ive pretty clearly already done my homework. Thats why theres a Nexus sitting on my desk now, and the DIYPNP with BT adapter will go back in the car after it comes back from paint. Thats why its also been tested with the current tablet I have, including the response time issues, which are non-existent.

I've already done this,

Using the Serial to BT adapter from DIY.

There's too much lag between the guages and whats actually happening for it to be a realistic option.

Might be ok for guages that are relatively static, CLT etc, But it couldn't keep up with a simple rev, Let alone boost or anything like that.

edit: uploading video now.

To start, I think the original idea is good. Response times always exist, it is just a matter of of whether it is human perceptible and whether your setup works reliably. If this setup works for you great, I'm happy for you and the people who can follow the same path.

I was only talking about OBDII as mentioned each time, not about your application specifically. Not every post is about your application specifically. Mine was a general post to help people considering this option with OBDII. The reading comprehension point is ironic as I am only referring to OBDII low speed and never referred to your application.

To simplify my point, if anyone uses low speed OBDII they will likely end up with a gauge running at 1-2hz making it a poor gauge.

On the issue of thermal shutdown and thermal runaway in lion cells (not the same thing), racecar or not doesn't make it better. Many tablets will shutdown at temps easily seen in a passenger or racecar interior with direct light on the screen. Some of the cars I run in have 130F+ ambient temps and far higher dash temps so we use coolshirts. A closed racer or passenger car, parked on asphalt with a black interior can easily reach 130F with dash temps that easily exceed 160F which, if exposed long enough goes beyond the limit of many phones and tablets. Again, this is a general point and not specific to you just a warning to people considering a consumer tablet in automotive. You could be constructive and tell us where your thermal limit is before shutdown on your Nexus 7 to address this point specifically (remember to reach saturation temperature, not transient exposure).

Thermal runaway (a cell rapidly rising in temperature that can catch on fire and explode) can happen in high temps, due to a rapid discharge rate, due to cell inclusions (drive a nail in a lion cell), during a wreck and for other reasons. The only point I am making here is that you should treat a high power density tablet like a fuel cell right in front of your face that will pump out poisonous gas on failure. It is a needless risk in this situation as the tablet can come on with vehicle power. I'd recommend removing the battery for this application.

To be clear for you specifically, thermal runaway and thermal shutdown are relevant to your application and low speed OBDII is not.

On the argument about thermal issues in race car applications... You have a point, but consider that several, including myself, have been running real time race telemetry apps on consumer Android and IPad devices in their race cars for a few years now.

In my case I am doing this in South Texas, clearly a thermally challenging environment in the summer time. I have not personally had any issues with my devices, nor am I aware of anyone directly or indirectly that has had any issue. Personally, I have had my devices mounted high on the center of the dash, and at the top edge of the windshield in place of the sun visor. Both have worked.

So, thermal ruggedness is a good point, and it is possible it could be an issue, but empirical evidence would suggest that it is a low risk failure mode. Personally I would not spend hundreds more on a ruggedized tablet (if they exist, I have not bothered to look), or assume that using a consumer phone or tablet in a race car is a non-starter.

NASA 2013:

Sooooooo....... Anyone want a Nexus 7 and Bluetooth adapter?:jerkit: