Part 1 of the Helix Elevator covered the theory, design, and construction of the infrared train detection circuits for use in my helix. On this page I will capture how I installed the electronic components into the helix.

The first step was figuring out how to install the infrared LED and corresponding photo transistor to the helix levels for accurate detecting. Futhermore, many web sites recommend that you place the two infrared components at an angle to the track so that the gaps in between rolling stock don't cause the LED's to flicker (I verified that this was indeed an issue). My solution was to cut two pieces of 1/4" basswood stock to length so that they match the height of the helix levels (see photo on the right). I then marked off where the helix levels were on the basswood, and transfered two marks that identified where the LED and the photo transistor are to be located. The basswood is going to be glued to the sides of the luan board (subroadbed used in the helix) at each level, and the IR components will be installed at a 45-degree angle to the track.

Be sure to mark what is the top of the basswood stock otherwise they might not line up in the future. I also marked which one will hold the LED and which one will hold the photo transistor since the LED and transistor components are of different sizes. Then, using various files, I carved a 45-degree cut at each location. This angle matches the angle to which the IR components are to be mounted with respect to the track. Filing this takes some time and is tiring, but worth it. An advantage of this installation method is that the back of the photo transistor is automatically protected from stray light.

Next I drilled two holes in each carved-out section so that the components' leads could be fed through the wood. For the LED's leads I drilled # 58 holes and for the photo transistor's leads I used a # 66 drill.

Here is a photo of all the components installed. I made sure that all the positive leads for each component are on the same side. This will make it easier to install the wiring later. I built another set of these basswood stock for the other end of the helix.

And now for the exciting step - installing the basswood strips with their components to the helix. I first clamped a matching pair to the helix and used the proof-of-concept circuit that I had built to verify that the components lined up. It turns out that these components don't have to line up perfectly. Also, I did the test with the overhead fluorescent lamps on, and the system worked flawlessly (at least, after I hooked up the wires correctly!). When the helix is fully enclosed, the system will be even better. The photo below shows the LED strip being glued in place (I used yellow carpenters glue).

Below is a close-up photo (as best as I could get it in this dark area) of the two components.

Although the circuit boards and the wiring still need to be installed, a test run showed that the system worked perfectly. The IR components are quite forgiving.

The next step was to install the 20 circuits to the helix structure. I decided to simply glue them to the vertical posts of the helix. They are glued with Liquid Nails for Foam (I had a new bottle handy!). The glue is very tacky and sets in a few minutes, so there is no need to hold or clamp the circuits. (back of the helix)

To connect all these circuits to the LED's on the front of the helix, I decided to use ribbon cable. The cost is a bit higher, but the professional-look of nicely routed wires is worth it. It actually made installation easier, because I glued the cable to the helix structure using the same glue as mentioned above. The inset shows the cable as it came from Digikey (16-wire). The photo below shows the cables for the LED's in the front that are connected to the detection circuits in the rear of the helix. The cables are nicely routed through the structure of the helix base.

The final photo of the naked helix. All the wires on the front have been prepped. The helix is ready to receive its Masonite board cover.

After installing the Masonite cover and attaching the LED's to this cover, this photo shows one LED being lit up by a train moving through the lowest rung in the helix.

This last photo shows the helix cover having been painted. You can see the banks of LED's on the helix' front (lower-left in the photo).

The system worked flawlessly. It was comforting to see the LED's light up as trains moved through the helix. This became even more important later on when I placed a huge mountain on top of this helix, completely hiding the interior.