> [ Insert drum roll here ... ]
>
> I'm pretty psyched. After a few weeks of lots of datasheet
> reading, experiments and forum questions, my first PIC project
> works like a charm. Thanks for all the help PIClist'ers !
>
> I used one of the MPX pressure sensors and a PIC16F872 to create
> a vacuum/boost gauge for my car. Vacuum is displayed with a
> bargraph going downwards from the top. Boost goes from the
> bottom upwards. I've also added a peak-hold feature that shows
> the highest boost by keeping that segment lit. I later added a
> dimmer which dims all but the peak-hold segment. For dimming
> I created my own PWM-like system -- show the dim segments
> only every so many loop iterations. Bright segments always. The
> dimmer and peak-hold can be switched on/off with a couple DIP
>switches. Also, a few more DIP switches allow setting of display
> range and a calibrate mode -- switch to 000, turn ignition key on, and
> it will sample the current barometric pressure and use as the
> zero-reference. That is stored in EPROM.
>
> Circuit -- I decided to build a no-holes board (okay, 3 holes plus a
> couple for mounting the sensor/regulator) for this, and put the main
> circuit on one side and the power supply on the other.
>
> Some pics ...
> www.avn-tech.com/VBM/images/VBM_board_1.jpg
> www.avn-tech.com/VBM/images/VBM_board_2.jpg
> www.avn-tech.com/VBM/images/VBM_board_3.jpg
> www.avn-tech.com/VBM/images/VBM_display.gif
> www.avn-tech.com/VBM/images/VBM_installed_1.jpg
>
http://www.avn-tech.com/VBM/images/VBM_on_1.jpg
>
>
> So I posted a note about this device on an auto forum and have been
> flooded with emails from people who want one. So I am seriously
> thinking of making/selling this it. If I don't, I'll write up the
> project in detail and post.
>
> The next thing I have planned is to re-code and add in an absolute mode
> (vertical bargraph from 0psi upwards), and see if I can trust that the
> time between key-OFF thru key-ON to key-START is enough
> to sample the ambient pressure and set the reference then. And I
> have to cut the dash panel, etc to complete the installation.
>
> Then comes project #2 -- a boost controlled switch for the secondary
> (very noisy) fuel pump, so it only comes on when (or just before)
> needed.
>
> Cheers,
> -Neil.
>
> --
>
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