using modern electronics

[Frank's 49]

A while, back there was some discussion on adding a gps to the instruments available.  I recently tried a different approach, and just used an old cell phone.  My son had several old out-dated android cell phone around.  The were the so-called 'smart phones', ie they had a digital touch screen.  I took one, charge it up, and after turning it on deleted all his personal data.  Then I turned on the internet connection, and it connected with the wireless internet in our home.  (you could do this anywhere wireless internet is available.  McDonalds, Barnes & Noble, etc).  Once connected installed GoogleMaps (it may already be there), and then found some speedometer apps.  About a dozen were available for a free download.  I just picked one and installed it.  Now the phone will display the speed of any vehicle it is in, and you can check your existing speedometer and odometer.  It also does not care if you change the  tire size or the rear end ratio.  It can also be used as a GPS.   You can even see how fast you can run! 

 

[HotRodTractor]

I'm working on putting together one of these trucks for a daily driver - while I do plan on having a full set of functional gauges - I also plan on having an Android radio head unit for GPS, radio, playing mp3s, etc.... I'm basically planning on installing a glove box door on the driver's side where the optional radio would normally go and having tabs on the door. When at a show - pop the door on. When driving around take off the door and stash it away somewhere. With the Android radio it would be very easy to use for a speedometer id I so desired.

[The Oil Soup]

If an old phone is used do you need to pay for some sort of service to use it as a gps? I am behind the curve on the whole cell phone trend.

[HotRodTractor]

11 hours ago, The Oil Soup said:

If an old phone is used do you need to pay for some sort of service to use it as a gps? I am behind the curve on the whole cell phone trend.

Nope. Its basically a mini-computer and the GPS satellite system doesn't require the cell network to access.

I haven't looked around much for one yet, but it wouldn't surprise me if there wasn't a good app to help calculate horsepower. I know some exist, but I think most of them require an OBDII port. With the built in accelerometer in the phone it should be possible to just utilize that and set up a test where you take off from a stop. Add in the rolling weight of the car, cargo, and people in it, and you have all the basis for generating horsepower. Not as accurate as a dyno, but could be useful.

[NiftyFifty]

Just be careful using those as a speedometer on the highway, gps on certain devices is allowed to be out by a certain % and some a lot more then others, and even some apps show different..it's not a whole bunch, but if you were on the highway and already possibly pushing things, it could be out a few mph and have you over what that cop deems ok that day.  There are actual speedometer gauges you can buy and mount permanent that look like classic gauges that use a gps unit mounted in the truck and no subscription needed, and no worries about forgetting phones or dead cell batteries..but they are a bit pricier then most gauge sets, and are only 12volt I believe.

[Frank's 49]

4mula-dlx:  The last thing I worry about is being over the speed limit! lol.  I looked at the "speedometer gauges", but only found 12 volt, and you are right, they are costly.  The  old cell phone thing was done to check the speedometer, and was done at basically zero cost.  Already had the phone, and the apps were free.  And now it also works for a free gps.  And HRT is correct, no phone carrier service is required.  FYI, you can also use a 'non-service' phone to acess the internet using any wireless internet service (like at many restaurants, etc.  

[Jeff Balazs]

The other option is to use a heads up display GPS speedometer. Mine is smaller than a pack of smokes and is plugged into a 12 V cigarette lighter. It is very accurate and is super easy to see. They are about $60 on ebay.

Hth, Jeff

[The Oil Soup]

Jeff, which unit are you using from eBay?

[TodFitch]

I mounted a small 6V+ to 12v- inverter/converter under my dash and brought the power from it out to a lighter/accessory plug mounted on the lower edge of the dash. I use that to power my phone while driving. It is actually overkill as it can put out 10w or so and the phone draws way less than that.

Regarding using an old Android phone: If you use an app like Maps.me or Osmand then you can download the vector maps for your entire area (or the whole world if you have enough space on the phone). Once the maps are on the phone there is no need for an Internet (data) connection so you can run the phone with no mobile plan at all. Set it up at home on your WiFi and you are done.

Regarding GPS speed issues: I think they are all the result of how good or bad the GPS chipset and logic are in your particular device. The position reports from the GPS in my phone are far less consistent than those on my dedicated Garmin GPS device. Position reports that bounce around a lot result in speed estimates that bounce around. Even with the relatively poor GPS in my phone, the speed reports are within a couple MPH of my actual (as determined by my speedometer and my good Garmin device). If you are using the phone GPS to try to maintain the speed limit you will be close enough that you won't get a ticket. At least that is my impression/observation based on using my phone for navigation in my cars.