Need advice for upcoming project

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Thread Starter


Joined Dec 12, 2012
Greetings all!
New to the forum here but hope to enjoy my stay. I am currently in the research phase of my next project but have hit a wall as my lack of experience in the field has stopped me from progressing further. I have attempted several searches to no avail.

Hopefully I can make the project description nice and concise so everyone can get on the same page:

I am planning to prototype a simple multiple sensor display for my vehicle.
- LCD is a HD44780 based 16x2 character display (chosen to match aesthetics of car dash)
- Will monitor 4 thermocouple inputs via 4 MAX31855 (based on advice that it isn't a good idea to multiplex TC's...someone can enlighten me on this because I'm not exactly sure why)
- will monitor 3 general 0-5v inputs (TPS, Pressure sender output & aftermarket Wideband O2). Code will convert to proper units and write to LCD.
- will monitor RPM wire from stock ECU. Not exactly sure how I will go about this yet. Some sort of frequency measurement?
- at least 3 buttons for input (scrolling, etc)

Now my main hurdle is I would also like to also develop an Electronic Boost Controller within the same unit. I would like to be able to use the inputs above along with manifold pressure via a MPXA6400AP IC. From those inputs I want to implement some PID control to maintain boost pressure by controlling the duty cycle of a stepper-based boost solenoid in the engine bay. Obviously input would also be required to set target Boost values, PID parameters, etc.

Now before anyone jumps the gun, I am still early in the development stages as I suspect a lot of reading and learning ahead of me. The PID control aspect I have covered as a colleague of mine is very proficient in the field. What I would like to know is whether my proposed device is practical from an engineering point of view.

- Will the accuracy and speed of the PID control be affected by the microcontroller also having to monitor several other inputs at the same time?
- Would I be better off designing these as seperate units?

Sorry for the long post but I've tried to be as descriptive as possible. Any advice/help would be very much appreciated.



Joined Mar 31, 2012
While I wish you luck with your project, unfortunately here is not the proper place. The owners and admins of this board have chosen to forbid automotive modifications as a topic of discussion here, for a variety of reasons (none of which are up for debate -- it is, after all. THEIR board and, therefore, their rules).

Check out the following sticky:

There you will also find some recommendations and pointers to other forums that are more receptive, or even dedicated, so such discussions.


Joined Mar 24, 2008
The owners of All About Circuits has elected not to host discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

This thread is against the AAC forum rules, Chapter 6, as seen here:

6. Restricted topics. The following topics are regularly raised however are considered “off-topic” at all times and will results in Your thread being closed without question:

  • Any kind of over-unity devices and systems
  • Automotive modifications
  • Devices designed to electrocute or shock another person
  • LEDs to mains
  • Phone jammers
  • Rail guns and high-energy projectile devices
  • Transformer-less power supplies
This can be found in our Terms of Service (ToS)

Automotive modifications of any kind are strictly forbidden. Therefore, this thread will be closed.

Please try to understand the reasons behind this action, and feel free to browse and use the forums.

You might find answers to your questions in one of these forums:

Another good forum that shares many of the same membership is . Good luck.
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