Sim. Racing Pedal Project #1

Introduction

My first attempt at building pedals has reached a usable state, so I am going to use them as they are and see how the work and hold up. The pedals turned out nothing like I had planned, but I forged ahead making design changes on the fly. Bottom line, the pedals work well and feel better than any of the "standard" pedals that come with consumer grade wheels.

Project Limitations

I couldn't do anything that required welding since I don't have the equipment or skill. I wanted to use gears on the potentiometers, but since I don't have a drill press, that was out of the question because I had no way to make precision holes for mounting bearings and shafts. The pedal were to go on my race frame and that did make some things easier (such as how to keep them from moving around on the floor) but it brought up its own limitations. My computer desk has a bottom shelf that is a main support piece and since the race frame slide under that, I had to make sure that my design would go around that shelf.

Design

I loosely modeled the pedal from the dimensions of those in my street car. I did the same thing when I built my shifter, and the familiarity is nice to have even thought the pedals in my street car could be placed better. So this mean top mounted pedals.


Top pedal design made me use extensions in order to get enough travel. I wanted to keep the potentiometers on the top to use the space on the bottom to get good solid stops.	The 3 2x2s on top set how far forward the pedals can move. The horizontal 2x4 serves as a back stop. The brake has an additional piece to limit its travel. Under that are layers of different rubber material. This give the brake a good progressive feel.

The main force comes from the brake pedal. The angled 2 pieces of wood transfer that down. The reason for not putting vertical legs on the back was because they would not have allowed my to push the race frame completely under my computer desk.	Each pedal has 2 springs. Although they look robust, they are not. I may replace the ones on the gas and clutch with heavier ones. The brake is already taken care of.

Electrical

The electrical part was already in place from when I built my shifter. The connection is through the joystick port and the controller looks like a CH Virtual Pilot Pro. See http://www.massey.ac.nz/~jcmarsha/Wheel/hshifter.htm for details. One day I will swap this out for a USB controller such as the Plasm-Lite board http://www.betainnovations.com.

Mechanical

My main concern was getting enough travel on the potentiometers (100K). In order to increase the travel, I made extensions off of the pedals. The further way you can get from the center of rotation, the more movement you get (the bigger the arc). Even with this design I am still not using the full through of the potentiometer. Fortunately the joystick calibration routine will see what you give it and spread that out over the entire range. This even works for my brake pedal and it has very little movement.

The only specialty part I used is thy nylon piece that goes on the potentiometer shat. It is a piece used in building radio controlled airplanes. When used on a plane, it is called a "steering arm".

Mounting

The pedals are just sitting on the race frame. The only real pressure comes from the brake pedal. That is almost completely forward motion. The pedals are kept from moving forward by the small square blocks you can see near the end of the frame rails in the picture on the left. After some use, I'll see if they need to be better secured.

Race Frame In Place

The race frame was designed to slide under the computer desk. I then pull the monitor and speakers forward (for maximum immersion.) By having the frame under the desk, this means that when in place, I can't see the pedal assembly (so I don't have to worry about it being raw and ugly :).

Hopefully you'll get some ideas from this. Have a successful project!

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