HO-Scale Tree With Train Sensor

HO-scale tree with reflective IR sensor that detects passage of train.
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updated December 1, 2023

Description

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These HO-Scale trees were originally created by Mckinze Malinowski in OnShape Public Documents, and modified here by addition of a reflective IR sensor to detect the presence of passing trains. 

https://cad.onshape.com/documents/2dcb8ec03cc26b4801efb277/w/8ddc2be215715e426fb46fab/e/7f554fb7ab7fb6076e6b9f27

The trees are of two different heights: 175 mm = 50 feet and 240 mm = 70 feet in HO scale.

The side-view reflective IR sensor was purchased from an on-line vendor for less than $1.00 each. The pins were bent from their original vertical orientation to horizontal. Small pieces of plastic foam were added to adjust the distance between the PCB and the tree trunk, and to keep the sensor from shifting around. 

Pieces of double-sided tape were added to the trunk branches to grip the leaves. Then #2 x 3/8 inch flat-head sheet metal screws were used fasten the two halves of the trunk together. The holes will probably need to be reamed out with a drill bit to make the screws go in easier.

The sensor has either analog or digital output and can be powered by either 3.5 or 5 volts. A hole in the trunk allows adjustment of the analog-to-digital threshold of the output. Connections to the sensor can be made using the female ends of male/female jumper wires. An Arduino-compatible micro-controller makes easy sensing of the digital output and control of the level crossing signal. The sensor range is about 2 inches.

Using a pair of trees, the crossing signal will be active before, during, and after the train passes.

 

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Model origin

The author remixed this model.

Onshape
cad.onshape.com

Differences of the remix compared to the original

Modified here by addition of a reflective IR sensor to detect the presence of passing trains. 

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