Arduino based LCD dashboard for 1980's non-canbus motors?

[johnbullas]

I am looking for a pointer towards a resource that will help me create an LCD dashboard for my 1983 Austin Mini.

I am looking to take 0/12v switched (tacho) 0-10v variable temp/fuel, pressure (0-90psi oil & vacuum) and pulses from the speedo cable to deliver a multi plot digital dashboard.... why????..... because!

I have read with interest of the ODB-II? solutions on this forum but I am really dealing with old skool here!

Any pointers to successful projects most appreciated, I do have a first generation Raspberry Pi kicking around as an alternative......

Kind regards

Dr B

[freebeard]

So it's been a while with 0 response. I commiserate because I drive a 1970s car that has a mechanical speedometer, an a electric gas gauge and that's it.

So what background do you have in hardware/software development. Your going to need a Step 2.

With that many inputs and an unspecified LCD output, I'd consider adding a CAN bus. And use a tablet for the display, then you won't have to reinvent things like touch input. There should be lots of open source activity in that area. Have you looked at EVTVs Aurdino Due based boards?

[johnbullas]

Since originally posting I have got a hold of an Arduino Mega and am I am awaiting receipt of a couple of voltage converters 12v>3.3v ( for the variable voltage the oil 0-100c and water temp 0-120c senders delivers) and a 3.3v 0-100psi pressure sensor for the oil with a view of another for the fuel pressure (0-15psi) ...

....... I have set up a dummy code set on the 2 x 40 character display I also got hold of.... and this is formatting perfectly.... hopefully I can convert the voltages to pressures & temperatures to display since the board has a gazillion analogue inputs!

The tachograph will need more work (hall-effect boards on ebay?), ditto a detector on the speedo cable (I might resort to a magnet fastened to the CV joint instead.)

I will report back as things come together

Dr B
Southampton UK

[freebeard]

Sounds like you have a handle on it. What do you think of this as a search criteria?

https://www.google.com/search?q="Ard...oftware+-ODBII

[johnbullas]

"Arduino Mega" gas mileage software -OBDII works well

I initially thought about stripping a cambus OBDII loop out of a more recent car but I am now looking at simply taking feeds off of the existing analogue resistance-based senders (ie the old skool senders, the speedo and tacho (both cables using hall effect transducers (probably) ) and connecting to the analogue inputs of the Arduino Mega via voltage sensors/isolators!

[gumby79]

If your speedo /tach cable are,A) the same b) like General Motors Dodge and Ford then try something like this https://www.alligatorperformance.com...crIaAgjX8P8HAQ

Or http://www.carparts.com/details/Dodg...HAQ&redirect=1
Option 2 has electric and macanicel outputs so that you can keep the stock stuff working. My 91 Dodge Ram D250 uses this sender 35usd @ Carquest auto parts had to replace last month.
I am interested in doing this as a means to do less Than full tank (500-700miles per tank too many cold starts @below freezing ) mpg analysis and data loging.
1or 2of theas flow meeter 2 if you have a bi pass presser regulator.this sender has a +-.5% accuracy
Ill be watching your development. As No computer =No valid mpg results. To many people lie about thire results.
I'm looking at the new RASPBERRY PI 3 ON SALE NOW AT $35 to use with my old android phone as a display and tuch interference. It has Bluetooth and WiFi built-in,less parts to get.
With all the improvements in CDA/ aero I've made and developing , my Dad a 45year multi million mile Over the road trucker is considering buying a same make, modle, year,and trim level truck to see how his driving style will effect mpg compared to me as well as a stock reference With this device we can eliminate the vehicle specific vereables ,eg drivetrain worm-up time due to different gear mesh within tolerance ,to get an accurate comparison. And with modds duse this ______ tweak help or hurt with out 2000+mi and possibly 4 month get an answer.
Gumby stay flexible.

[johnbullas]

OK, an update

I now have an Arduino Mega and an LCD display with a shield (aka interface) for the Mega so the two can comfortably talk to each other

Reading around the subject it appears there are a wealth of cheap little stepdown devices to reduce the voltages behind the Mini 1275GT dash to the 3.3v or less the Mega can handle

The oil pressure, water temperature, oil temperature and oil pressure senders all tell the gauges what to display by increasing the voltage they can pass the the pressure or temperature increases, the variability of the reference voltage needed by the gauge means some are powered off of the voltage stabiliser (10v) other senders work with gauges using the system voltage (notionally 13.6v aka 12v).

In all these cases, the voltage passed by the sender unit will have to be mapped to enable the voltage at the Mega (via the stepdown) to be converted to a displayed value.

In the case of the tachometer (rpm) a 0/12v pulse exists for the Mega to monitor

In the case of the vacuum gauge a custom pressure/vacuum measurement device is required

In the case of speed the rotation of the speedometer cable needs to be monitored (and a turns per mile value used to convert to speed) else a hall effect transducer will need to be used in association with a magnet fastened to the rotating CV joint on the transmission (coupled to the road wheel) - alternatively chopper type detectors reliant on the passage of a chopper disc through the sensor might be viable but the chopper on a motorcar is typically part of the hub and the ABS braking.

I have produced a Flickr photo album of the items identified to date

Once I get something working I will update thing, I have the LCD displaying dummy outputs so making good progress!

[gumby79]

Originally Posted by johnbullas

In the case of the tachometer (rpm) a 0/12v pulse exists for the Mega to monitor

In the case of the vacuum gauge a custom pressure/vacuum measurement device is required

In the case of speed the rotation of the speedometer cable needs to be monitored (and a turns per mile value used to convert to speed) else a hall effect transducer will need to be used !

The VSS senders I linked will provide this at a much higher resolution than 1pulse per tire revolutio. I used this one SPEED SENSOR, MECH TO ELEC, GM & CHRYSLER, 7/8"-18 THREAD, HALL EFFECT, 16 PULSE
On my 79 K-20(3/4ton 4X4 Chevy). When I custom built the dash all electronic. Something like 32000 pulses per mi on 33"s and 4.10's. Its been 9 years and no longer have the truck. As a bonus your stock mechanical speedo can be retained this just plugs inbetween your cable and Trans.
Gumby stay flexible

[johnbullas]

I have an Arduino Mega 2560 board and 2 x 40 LCD and the code ready to take in the data from 3 analogue sensors and the voltage,

I am waiting for some temperature senders (sic) to set up the A>D conversion for those via some ebay sourced voltage converters.

I am also considering the VSS technology described in the reply above to translate speedo cable rotation (measured using an opto-sensor) to a pulse to trigger a BMW motorbike speedo (electronic and £20 in ebay if you look)

I have added some poor quality video of the progress on my YouTube channel search: "Arduino Mega 2560 johnbullas" on youtube

The code enables upper and lower limits to be set and for Lo or Hi alerts to be flashed!