Guide to Creating a Full re:Invent 2018 DeepRacer Track in 7 Steps

ARCC
8 min readJul 13, 2019
Completed track

Additional Resources:

Time: 4–5 hours with two people working together

The first quadrant took about 1.5 hrs to get perfect. The next 3 were easier as we got better with practice.

Cost: $450 and up

Foam tiles are the largest cost component. Consider an early purchase, price comparison, or used/renewed version to save money.

Note: Considerations for Model Performance (from AWS guide):

How you build a track can affect the reliability and performance of a trained model. The following are factors you should consider when building your own tracks.

Do not place any white objects on or near your track. If necessary, remove any white object from the track or its vicinity. This is because training in the simulated environment assumes that only the track borders are white.

Use clean and continuous tape to mark the track borders. Broken or creased track borders can affect the trained model performance.

Avoid using a reflective surface as the track floor. Reduce glare from bright lights. The glare from straight edges can be misinterpreted as objects or borders.

Do not use a track floor with line markings other than the track lines. The model might interpret the non-track lines as part of the track.

Place barriers around the track to help reduce distractions from background objects.

Step 1: Gather Materials

  1. Tape Measure
  2. Minimum of 3 boxes of EVA foam tiles (36 tiles each box, size 24”x24”x1/2”) that can be purchased at either Walmart 573588438 or Amazon B01IDRWPG8. You will need at least 83 tiles for the track (5 boxes)while the full grid requires 117. Walls will require 88 tiles (2–3 additional boxes) if desired. The wall is optional and will be constructed in the style of A-Frame Sidewalk Curb Sign.
  3. Two white duct tape (1.88 Inches x 20 Yards) that can be purchased at either Walmart 553230113 or Amazon B072JP1L2R
  4. One yellow duct tape (1.88 Inches x 20 Yards) that can be purchased at either Walmart 553154961 or Amazon B003YH9674
  5. White gel pen for temporary sketch lines and curves as well as naming the tiles. Buy this at Amazon B075VLPL1B
  6. One pair of scissors.
  7. Two Exacto knives for cutting duct tapes to separate tiles. Walmart 550879505 or Amazon B0006NAU6U.
  8. One protractor to measure the starting & ending points of curvature. Amazon B00004T7TB.
  9. One t-square or long ruler for straightaway marking & measuring yellow tape.
  10. Six cam buckle lashing strap for foam tile storage and transportation. Amazon B06Y5FDX7H. Also check out the cam buckle Instruction Video (Start at the 1:30 timestamp)

NOTE: If there are more than two people working, then get more tapes, markers, scissors, and knives so the project can be easily divided among more people and into quadrants in order to be worked on simultaneously to save time.

Step 2: Find a space to build the track with at least 10’x14’ dimension (26’x18’ is not needed if we build in Quadrants!).

Diagram for naming tiles and laying out the track (Figure 1)
Dimensions are in inches and degrees (Figure 2)

We found that building quadrants in order of 4, 1, 2, 3 was the most efficient based on the numbering of the quadrants as in figure 1. This also makes the starting point really easy to find and mark on tile M6!

Make sure to use the smoother side of the foam so that the tape sticks better!

Step 3: Layout and build quadrant 4 (G5-M9) of the track as shown in figure 1. Use figure 2 to help see dimensions. (~ 1 hour 30 minutes)

Find the starting point of the track in tile M6. We shifted the track up a bit in fear that we would hit the edge of the tiles on the bottom. This would have made separating rows 8 to 9 difficult. However, we found that it made little difference. If for any reason you end up getting to the point where a long strip of tape falls on the boundary between two rows then adjust accordingly as long as the track width remains within 3 inches of the desired 2-foot inner-edge to inner-edge thickness.

Start to layout the track using the white gel pen to temporarily sketch the lines for the track. Track width (inside) should be 24 inches +/- 3 inches at all places! Reference figure 2 for the track dimensions including radii of curvature and the degrees for each turn.

In order to make the turns, put the tape measure (or extra long ruler if you have one) at the center of the arc. Line the edge with the marker up with the starting point of the turn (outer part of the outermost piece of tape). Pivot the ruler and use the marker to draw the turn before adding tape segments.

Place the tape over the marker lines (lining up each piece to either the inner or outside edge as best as possible). Length of the tape segment for the turns depends on how tight it is, try to make each piece between 1–2”.

If no turn then you can use a straight piece of tape.

Add yellow tape for center dotted lines. Each piece should be cut into 1” x 1.88” segments and spaced out by 2”. (We use the width of t-square as a spacing guide.) With the t-square, you want to make sure that the T remains perpendicular to the edge of the track to ensure that the yellow tape points parallel to the track (see image).

Label each tile with the system shown in figure 1. Be consistent. We labeled at the top right corner of each tile.

Use the knife to cut the tape at the border of each tile so the individual tiles can be separated. We

Do not remove all the tiles when moving on to the next quadrant. Use the border tiles of the finished quadrant to start building the next quadrant. Be careful to make sure that track lines up between quadrants!

Step 4: Layout and build Quadrant 1 (G1-M5) (~ 45–60 minutes)

Follow steps 2–9 of Step 3. Make sure to line up the track with the edge G5-M5. See images and time-lapse video for further guidance.

Step 5: Layout and build Quadrant 2 (A1-G5) (~ 1 hour)

Follow steps 2–9 of Step 3. Make sure to line up the track with the edge G1-G5. See images and time-lapse video for further guidance.

Step 6: Layout and build Quadrant 3 (A5-G9) (~ 1 hour)

Follow steps 2–9 of Step 3. Make sure to line up the track with the edge G1-G5. See images and time-lapse video for further guidance.

Step 7: Pack up your track (~ 20minutes)

If you have the room and extra time, you can set up the whole track and give it a test (like we did). If not, pack up your track with cam buckle lashing straps. Make sure the tiles can easily be re-deployed and there are no major problems that could affect model performance (bend tiles, peeling tape, etc.).

It will take about 45 minutes to deploy/redeploy the track with one person and another 15 minutes to lay out the wall border. A similar amount of time is required for taking it down.

Example of how to set up walls if you choose to do so.
Cutting apart the tiles of the last quadrant to be completed and packing the tiles into 4 stacks (5–6 including walls).

That's it! Now you have a nice and durable DeepRacer track that you can use with all your friends or with your DeepRacer team. Part of the challenge with DeepRacer (or any other reinforcement learning car) is the transition from the simulation to the real world. It is impossible to account for all the minute physical interactions that occur in the real world in the simulation. Therefore, overfitting can be an issue that effects model performance.

A good track means a happy DeepRacer!

If you are new to this blog make sure to check out our other posts such as our introductory post here! The Autonomous Race Car Club (ARCC) is designed around teaching AI and machine learning, two critical technologies, through the lens of autonomous racing. Content covers a wide array of machine learning topics and is aimed for people of varying experience. ARCC also hosts competitions and educational outreach events for middle and high schools.

--

--

ARCC

Organization founded to inspire and teach people about AI and Machine Learning (ML) through the application of autonomous race cars. See arcc.ai