Automotive 20x4 chars LCD Display

Hi there,

I'm working on a small automotive display, using the following stuff:

• Olimexino STM32 running the latest Espruino 1.65
  
• a 20x4 HD44780 LCD 5V (white over blue) for which I'm using external power (and not the 3.3V the Olimexino board provides)
  
• a Terratrip speed cable sensor (dedicated racing solution, easy wiring)
  
• Simple Voltage Sensors (up to 25VCC, but my truck is 12VCC so it should be fine) to measure various auto probes - these are from robotbase.cn
  
• and finally a DS18B20 temperature sensor for outside temperature.
  
  

I've picked the Olimexino because it's noise immune, has a more industrial touch and is easily powered by 12V/5V/etc.

So far I've managed to:

• flash Espruino 1.65 to the Olimexino STM32 board
  
• wire up the LCD and display a mock-up of what I want to achieve
  
• run the Date/Time test app
  
• build a small app to read voltages using the analog voltage sensors - which I've used to measure every charger and battery in the house - and it works great. I intend to use this to plug to various auto probes but mostly to check the level of battery charging the alternator delivers - in real time.
  
• write this post
  
  

I'll try to update as often as I can with code if anyone is interested.

The information displayed is (left to right, row by row):

• current speed | current date/time
  
• current rpm | exterior temperature
  
• partial odometer | engine coolant temp
  
• total odometer | battery charging level
  

1 Attachment

Wow, it looks great!

How do you measure the RPM - or is that faked for the moment?

For the moment everything is faked - but I do have the code working for the voltmeter, time (doh!) and exterior temp.

I intend to get the RPM from the alternator, which is a somewhat used method. It will involve some trial and error, but no biggie.

Ahh, neat idea. If you've got coil on plug ignition you might be able to take a feed off that. On mine it's just a simple 5v signal!

Alas, it's a four pot diesel. This isn't the ignition you're looking for... :)

you might find this useful: https://youtube.com/watch?v=t0ToYhjYV9I

Thank you. That is very interesting, but it's still for gas engines, whereas I run a diesel, hence there is no ignition coil to kick :)

You could probably take it off the common rail diesel injectors if you needed to. An opto-isolator would protect it nicely from any back-emf.

I'd be interested to see how it works with the alternator - would you be trying to measure the fluctuations in voltage coming out of it?