Carduino

Manager: Michael Kuba
Premise: Use an Arduino, pressure sensor and other parts to create a customizable boost guage.

BOM

  

$20

Arduino Uno

 

$35

Honeywell Pressure sensor

SSCDRRN030PDAA5

$0.75

7805 voltage regulator

 

$1

Assorted resistors

 

$40.50

Adafruit goodies

 
 

$6

JST SM Plug + Receptacle Cable Set x4

 

$13

LCD display

 

$2.5

Waterproof Polarized 4-Wire Cable Set

 

$10

i2c / SPI character LCD backpack

 

$9

Adafruit Perma-Proto Quarter-sized Breadboard PCB

$10

misc wire

 

$5

Tubing connector

 
 

Code

http://pastebin.com/Dbtg1Fb5

 

Total: $112.50

 

Background information on the Arduino board: http://arduino.cc/en/Main/ArduinoBoardUno

 

The Honeywell sensor I used has three leads - ground, positive data, and negative data (negative data just flips the voltage). Positive data goes to pin A0 on the Arduino. Recommend consulting the datasheet with your specific sensor - I used SSCDRRN030PDAA5, but significant construction benefits could be found using a sensor with a larger connector. I recommend staying with the SSC series - the NSC series, for example, is uncalibrated and outputs a raw signal, while the SSC series outputs e.g. 0-5 V. Slight changes to the math in the code might be necessary. FYI - The math in the code has been optimized by using integer math.

 

I used the Perma-Proto quarter-sized breadboard pcb to connect wires to the Honeywell sensor. I cut another one in half and used it for pin breakout on the Arduino board, as well as a place for the 7805 voltage regulator. The voltage regulator was used to drop the 12VDC commonly found in cars to 5VDC for the Arduino and Honeywell sensor. Since the voltage was now regulated, it was connected directly to the 5V pin of the Arduino board.

 

Theory and assembly of the i2c/SPI character LCD backpack and LCD screen can be found here: https://learn.adafruit.com/i2c-spi-lcd-backpack. The code I used was pretty much copy and pasted from there, using the same wire connections.

 

The i2c LCD backpack has been optimized by using the LiquidTWI library, shown here: http://www.youtube.com/watch?v=IpwqGJwn1FY (link to library is in video description)

 

I used the JST SM plugs from Adafruit to connect the arduino and LCD screen circuits for ease of installation into the car. I used the Waterproof Polarized 4-Wire connector for the connection to the actual boost gauge circuit, since it was in the engine bay.

 

There is an option in the code for personal preference or debugging: on line 14, the code is:

boolean minmax = false;         //flag for boost graph or max and min boost

The flag “false” can flipped to “true” to display the minimum (read: vacuum) and maximum boost levels since the gauge was last turned on.

 

I used an SLA to build the cases for everything - there is a box for the pressure sensor board, a box for the arduino, and a box for the display. The display box is a little small for my display, I had to widen it by about 1 mm all around. I also filled the pressure sensor board box with an electronics potting epoxy to protect the parts from any weather the car might see. STL part files here: https://www.dropbox.com/sh/ew7orezujg0shs8/AADgiSFyteHLHVaF0Uk0SBtVa

 

More ideas on the build: http://www.seatcupra.net/forums/showthread.php?t=348592


 

Posted by
Michael Kuba's picture
Michael Kuba
on Tuesday, May 27th, 2014
Filed under arduino diy
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Agenda

Sunday, April 22nd

  1. Open Build Something!
    • Start time: 07:00pm
    • End time: 10:00pm
    • Where: 2215 Scott Ave, St. Louis, MO 63103, USA
    • Come stop by and visit! Open build night to work on projects and hang out!

    • View this event in Google Calendar

Tuesday, April 24th

  1. Class: 3D Printer Basics

Thursday, April 26th

  1. Armoring Class: Riveting Basics
    • Start time: 06:00pm
    • End time: 09:00pm
    • Where: Arch Reactor, 2215 Scott Ave, St. Louis, MO 63103, USA
    • This is the first of a monthly class series on Armoring, with an emphasis on SCA (Society For Creative Anachronism) legal armor. These classes will be co-hosted by Amberly Brown and Mike Martin and open to anyone with an interest in Armor for SCA, LARP, cosplay, etc.Riveting Basics:

      • What type of rivet should you use for different materials.
      • Tips and tricks for riveting in tight places.
      • How to rivet joints and other flexible connections.
      • Discussion, hands-on examples, and open time to work on your project with two experienced SCA fighters and armorers.
      • Rivets and some strapping leather will be available (copper, hardened aluminum, and brass rivets. Black leather) but if you have your own, please bring it.
      • No cost, but donations to AR are always welcome.
    • View this event in Google Calendar

Friday, April 27th

  1. 3D Printer Meetup

Saturday, April 28th

  1. Sewing Cat Trap Covers & Stuffing Catnip Mice
    • Start time: 10:00am
    • End time: 02:00pm
    • Where: 2215 Scott Ave, St. Louis, MO 63103, USA, Arch Reactor
    • Please join members and supporters of St. Louis Feral Cat Outreach at Arch Reactor (2215 Scott Ave, 63103, behind UPS) to help sew trap-covers which they will use when trapping kitties (for trap/neuter/return activities) and members of Stray Haven Feline Rescue to stuff catnip mice, on Saturday, April 28. We'll start about 10 and some of us will be there until at least 2pm, possibly later.

      For sewing trap covers, two or three sewing machines will be supplied but feel free to bring your own. We have plenty of table space for both sewing and cutting. For Mouse-stuffing, mice, fluff, and catnip will be supplied.

      Can't sew? Come help cut and pin or stuff mice or just help keep us organized!

      If you have fleece to donate, please bring it along (best if at least 30" x 36" pieces but we can make it work if smaller. Any other large pieces of fabric (like old, sturdy bed sheets) can also work for trap covers.

      The time of this event is flexible, so feel free to come late, leave early, or stay later than 2pm.

      Arch Reactor will be hosting monthly Board Game Day starting around noon but we have plenty of space to accommodate both groups simultaneously. If you like gaming, please feel free to join in that event which will run until at least 10pm, possibly much later.

      Soda and bottled water are available for modest donation. TJs pizza available for lunch if you wish for $10 each with a wide variety of flavors in stock or feel free to bring in a sack lunch. Microwave also available.

    • View this event in Google Calendar
  2. April BoardGame Night * ArchReactor
    • Start time: 12:00pm
    • End time: 11:30pm
    • Where: 2215 Scott Ave, St. Louis, MO 63103, USA, Archreactor, Arch Reactor
    • Come On Out and Play games With us. If you don't know games that's OK we are friendly and love to teach. If you do, bring your Favorites along and let get a Game in.

      We'll have Food there, and I'll happily take 5$ in exchange for letting you eat all day.

      We start at Noonish and Play until you Leave or after Midnight, whichever comes last. :)

    • View this event in Google Calendar