Forward Parking Assist - Circuit 3/9 (optional component)

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Major System Category: Electronics
Task: Run cables for forward parking assist sensors
Parts: Optional part (parking assist sensors)
Power Cell: 3
Circuit: 9 - ORANGE
Master cell: TAN/GREEN
Prerequisite Tasks: Mount the body
Additional Costs: $50
Time Requirement: 1 hour
Date Started: September 1, 2012
Date Completed: September 1, 2012
The forward parking sensors are an identical setup to the rear parking sensors. They came in the same kit. The differences are as follows:

• Wired into the brake switch.
• Mounted on the inside of the hood.

Forward parking sensors staged on the radiator aluminum box. There should be enough slack to route easily to the hood once it is mounted. Orientation: front of the car.

I currently, do not have the hood mounted on the chassis. I decided to stage the sensors inside the radiator aluminum. This is an area I reinforced for strength earlier in the build. I enclosed the sensor cables in wire loom, and ran the loom under the radiator aluminum wall through the steering rack mounts. I snaked the loom around the battery tray and behind the lower rear mount for the front control arms on the driver's side. I believe I can mount the control box to the inside of the body shell below the hinges for the hood. I have temporarily mounted the control box here.

Sensor control box mounted inside the body shell behind the front tire on the driver's side. There is  plenty of room to run the speaker cable up the pillar and into the headliner. Orientation: driver's side wheel well, taken from beneath the car.

I can route the speaker cable up the pillar and mount forward on roof under the head liner. There is a vendor that has created additional fiber glass pieces that for mounting gauges on the driver's side pillar and over head   parallel to the center tunnel. Even if I do not mount additional gauges, I can see the utility for these pieces.

Permanent home for the front parking sensor. The master cylinder are at the bottom of the photo. The red is part of the  body shell and the black angle piece is the wiper motor arm.

Update April 10, 2013: I got around to finding a permanent home for this module.I cut a 5 x 5 inch acrylic square (I have been working with acrylic to mold some pieces for a center console compartment.) I mounted the sensor module on the acrylic using 3M double sided tape, then I mounted the acrylic ahead of the wind shield next tot he master cylinders. I had to be careful not to cause interference with the wiper rocker arm. Once I am certain I have handle all the other issues related to the hood, I will mount these sensors on the hood. Right now they are on the reinforced section below the radiator.

Fabricated mount for parking sensor. This sits above the front grille on the ledge/ This is a great place to run wires/

Update August 10, 2013: Most of the summer was spent working on the body. The hood and body shell are at the point where I finished up most of the wiring associated with Power Cell #1. The front parking assist sensors are designed to attach to a surface using 3M automotive tape. This works fine for the outer sensors, but not for the two middle sensors. I entered up fabricating a mount from angle aluminum and 3M tape. I used the Loctite Epoxy designed for fiberglass and aluminum.

Parking Assist

I ordered the parking assist sensors last month. I decided to go with a 4 sensor set up for front and rear for a total of 8 sensors. Basically, you end up purchasing two 4 sensor kits. The purpose of parking sensors is to assist the driver with an audio/visual notification of obstructions within 5 feet of the front or rear bumpers.

This is one of the kits.

I already know that parking a car on the lift or under the lift will be a close thing. It is easy to park a car under the lift. It is harder to park a car going up the ramps and keep everything straight. I can park the Camry and Boxster without any problems. The minivan fits on the lift if you remove the side mirrors, so there are limitations to what I can park on the lift. The driver's rear view and perception in the GTM is minimal.

They sent me 2 sets of sensors. This is the basic set.

The sensors are  position inside the bumper fascia. This means it will be inside the fiberglass shell. Forward sensors are connected to the brake light. Rear sensors are connected to the reverse lights. You might think forward sensors are overkill, but I have discovered that parking the Corvette and/or the Boxster (with its new front end) can be a challenge as you just don't have a great sense for the distance between the front end and the curb.

This is the second set of sensirs that have double sided 3M auto motive tape.

The sensors connect to a control box. The control box is wired to a power source. Most likely with wire taps. This is very low power system. I will be employing LED lamps through out the GTM, so tapping these sensors into those circuits should be a minimal load.

Control box, power leads, buzzer and buzzer interface wire.

The control box has outlets for buzzer and display. I plan to only use a buzzer system. I will augment the parking assist sensors with forward and rear cameras wired into the stereo/Mp3/BlueTooth/GPS system on the center console. One of this year's projects is to upgrade the Boxster's electronics. I plan to add a camera to that project. I will use the Boxster as a camera test bed.

Control box with inputs for power, left sensor, left center sensor, right center sensor and ring sensor. Outputs for display and buzzer.

This set changes the ISIS wiring setup. At the time, I reasoned the parking assist required a separate circuit. Since this system is designed to piggyback on lighting circuits, there is no need for a separate ISIS circuit. The other change to the ISIS wiring diagrams is the elimination of a separate circuit for HomeLink. Since I am going with a GPS Navigation system on the center console, I can move HomeLink functionality to the rear view mirror.

Electronics Suite - Preliminary Decisions

Every guy I know love their gadgets. The GTM electronics suite is a vast opportunity to devise, scheme, plan and plot a digital cornucopia. With the order date for the kit a mere three and half months away, it is time to start making decisions. As with everything, decisions begin to narrow your options - this is a good and bad thing.

The CarPuter or Car PC is a powerful option. Mobile Computing Solutions is a great site to research the available options. Centerfuse Auto provides software framework to load apps (similar to iPhone and Droid) to a XP, Vista or Windows 7 environment. 

The CarPuter idea is seductive and extraordinarily powerful. Unfortunately, there are some red flags. Many of the apps rely on an external board connected to the CarPuter via a USB 2.0/3.0 cable (in some cases up to 10 possible inputs). I live in this world professionally, and my experience has been that trying to push a Windows OS with 6 USB inputs is iffy at best. This is going into a car. I need it to be reliable. The other warning flag was that people are relying on hacks to make things work (e.g. hand soldering boards). Again the reliability/kludge factor causes me to pause -  especially in a car capable of 200 (or better) mph.

I went with an independent TPMS system offered by Orange Electronics.  Most systems are rated to 7 years on the Lithium Ion batteries. This is a direct monitoring system. The pressure monitor is mounted on the inside of the wheel rim. I plan to mount the screen on the lower left hand side of the dash. This becomes critical in the build, as I want to get the car up on wheels no later than July. Therefore, I need a TPMS solution ready to go by then. This also means I have to decide on tires and tire sizes.

The electronic suite consists of the following:

• Parking Assist Sensors
• TPMS (My buddy Vern hates these things)
• AM/FM/DVD/BT/MP3/GPS/XM
• HomeLink
• Automatic Headlight Sensor (under $30)
• Auto Dim Mirror
• Compass
• Temperature
• Trip Computer
• Forward and Rear Cameras (Night vision is a plus)
• OBD II Diagnostics
• Cruise Control
• inTouchMax
• Seat heaters (this is a Minnesota car - needed for late and early season driving)

Directed Electronics 545T Nite-Lite System uses a photo electric sensor to measure light and automatically turns on/off the headlights, tail lights and parking lights as necessary.

The goal of the electronics suite is functionality. This means I need to pack a lot of functionality into a small number of versatile interfaces. One of the major driving factors is space. The GTM is not a Chevy Suburban that has boat loads of room. It is basically a cockpit strapped to a rocket motor inside an exotic body shape. The center console has room for a double din unit and the ISIS inTouchMax screen (after I move the shifter towards the rear). The ISIS system already has 1 Master Cell, 3 Power Cells and a inMotion Cell. These all need to be deployed out of sight, and they require flat mounting surfaces. ISIS localizes 95% of the controls to the inTouchMax screen. Add to this speakers and an amplifier (I'm thinking of hiding this under the passenger seat) for the sound system and there aren't many places to stick a CarPuter.

This is a Bluetooth enabled scan tool that is compatible with Droid, Android and Torque. Torque is an Android app that directly monitors the vehicle's ECU. I plan to use this with an Android (Samsung Galaxie II) tablet on an as need basis. I will test it on the Corvette and see if Torque lives up to its billing.

Since space is at a premium, you start asking questions:

1. Does the GPS and/or cameras get deployed to the rear view mirror or the sound system controls?
2. Does the sound system use a fixed screen double din solution, or a single din with a motorized screen solution?
3. Does HomeLink get deployed to the rear view mirror, or is it an independent 3 button solution? If so, is there room on the headliner?
4. Does the parking assist system use 4, 6 or 8 sensors? And how does it interface to the screens?
5. Do the OBD II diagnostics get pumped to a really ugly instrument panel (looks like a cheap 1980's Nintendo system)? 
6. Is a 7 inch touch screen large enough to adequately display the information?
7. Where do the compass, temperature, trip computer and map lights get deployed?
8. Is there even room to go with a paddle shift controller behind the dash or inside the tunnel?
9. Does the GPS software have a built in trip computer? If so, how good is it?
10. Is there a reliable vendor and method to update the GPS map and software?

For the parking assist system, I am going with  a 2 speaker, no display, 8 sensor system. One sensor on each corner, and two sensors on each bumper. I plan to deploy the speakers so I can differentiate the front from the rear. The rear sensors activate when the back up lights engage. The front sensors activate when the brakes are applied. The stated range is five feet. Each has an independent controller.

This is what planning is about. In the final analysis, the only place left for the CarPuter was under the driver's side seat. I'm not sure how much space there really is down there. I've started making decisions (without putting a lot of money at risk). None of them are cast in concrete - that's the beauty of building your own car. The thing I like about the decisions I've made is that they are simple, modular and easy to replace.