a multi-function display for isolde - part 3

This is the following on post to "a multi-function display for isolde - part 2". I am making some small progress on the programming, and more parts arrived. Among them is the 128x64 pixel OLED display that I was looking forward to play with.

While I know the OLED display is small, seeing it first hand is still a shock as to how tiny it is.

the tiny 128x4 pixel OLED display - the display area is smaller than a US $0.25 coin

also arrive is this oil filter adapter plate that costs just $16 shipped from China

I research the best way to add the oil pressure and oil temperature sensor and found that using a oil filter adapter plate is the best option, and allows up to three additional sensors to be mounted. I check fit of the oil filter adapter plate that I purchased with a Vanagon oil filter.

the adapter plate comes with two plugs

It has been an interesting and education experience doing this project. As I research the automotive gauges and sensors I saw a lot of commonalities of parts used by the vendors. It is one category in which you can spend more but seldom get more. Most of these branded web-based vendors just have the parts made by say some Chinese manufacturers with their own brand on it, and charge 3x the price premium. The oil filter adapter plate that I pay $15 is virtually identical to the ones sold by these vendors for up to 2.5x more.

At this point my biggest concern is the longevity of the sensors. I am very unimpressed with their construction especially they are bolted to the pressurized oil circulation system. My most discomfort is the oil pressure sensor potential catastrophic mechanical failure. I know it rely on a diaphragm inside to move a potentiometer. What if the diaphragm develops a puncture?

the silly robins decide to build a nest on my ladder - I would not use the ladder for the next two months while they start a family

steamed chicken meat with Chinese sausage, shiitake mushrooms, tree fungus, salted big head vegetable, and live clams

it turns out the oil temperature gauge and sensor are defective - they are sending me a set of replacement; these are very nice looking gauges for under $30 total for the set shipped

I spent some time thinking of how to use the joystick to navigate the multi-function display. I decided to code the joystick to mimic a switch type pseudo-joystick. This means making the X and Y axes potentiometers behave like on/off switches. This way the joystick gives me 5 switches to work with:

• Joystick stick center (neutral at rest)
• Joystick X left
• Joystick X right
• Joystick Y up
• Joystick Y down
• Joystick push button on/off

To live up to the multi-function display name, I have to implement some ability to select different information to display. I decided that first iteration is to implement a mean to scroll through a list of N lines of parameters, by displaying 4 lines. I want to keep the driving distraction to the minimum. To this the joystick just needs to be pushed up or down to scroll the lines up or down. The ordering of the lines are fixed and this is fine as the important parameters like oil pressure and temperature will always be displayed.

the 4 lines of parameters before scrolling

a new line of parameter (uC Temperature) scrolls into view and displaced the ambient air humidity and temperature out from the display bottom

While the program codes for the joystick and display scrolling are fairly simple right now that would not stay simple long. Once I started adding the data logger functions that include a real time clock the user interface will get very complex very quickly. The nice thing about software development is you can always develop and expand as time permits, as long as the hardware are properly designed and implemented. I am still waiting for the RTC and SD card interface module to arrive.

Right now the main functions that drove this multi-function display have all been proven concepts-wise.