Ashtray Display

1. March 2018


Another gimmick ... ;-)

It started with a simple requirement. In my daily car I have a metre for the oil temperature. It's amazing sometimes, how much longer the oil needs to get to a proper operating temperature compared to the cooling liquid.

So I wanted to include the oil temperature measurement into this car. But - as you've seen in the cluster section - there's just no space in the Cluster. So I came up with the idea to integrate a display into the ashtray (I'm not smoking).

So while I'm at it, an outside temperature would be handy as well. So I started fiddling and the same electronic circuit with the microprocessor drives that display.

I sourced an outside temp sensor from an old C-Class (W203) and an oil temp sensor directly from VDO. My math knowledge from school had to be dug out to find the formula for resistance vs. temperature in both sensors (logarithmic curve).

I designed a display holder in 3D, printed it out and it fit the display straight away. The display itself has 320x240 pixels, even touchscreen (not used at the moment). It took me a while to be able to show the Pick-Up-Bitmap on the display, but now it works.

That display cost an amazing amout of 9 Euros, the hours I'm not counting ;-)

Construction ...
Electronics ... connector on the left is to all car input
Et voila! (oil sensor not connected)