Trailer Side Indicator Lights

[Imsolidstate] is working to add side turn signals to a trailer. These orange clearance lights are illuminated when the vehicle’s headlights are on to increase a long trailer’s visibility. They also blink along with the turn signals on the back of the trailer. A standard 6-pin lighting harness doesn’t support this functionality so the trick is to add them without altering the towing vehicle in any way. He’s using an ATtiny24 microprocessor to interpret the logic from the vehicle and then translate the turn signal and tail light data into a signal for the additional side indicators.

McLVDT: A Straw-based Sensor

We saw [Kevin’s] home-built Linear Variable Differential Transformer in a YouTube video last week and wanted to know more. We’re in luck, he agreed to share all the details as well as a bunch of information on these sensors. An LVDT is used to measure distance along a straight path. Unlike a linear optical encoder, this method uses measurements of inductance between two electrical coils to judge the distance.

[Kevin] used some magnet wire wrapped around two straws of different diameter to fabricate his sensor. A signal generator is connected to the primary coil and the resulting signal induced in the secondary coil is measured to reveal the change in physical position. Check out the video after the break to see the results.

It’s not hard to get your hands on a McDonald’s straw (hence the name ‘Mc’LVDT), a smaller inner straw, and a few feet of magnet wire. This will be a fun one to try when those dark winter days start to get to you.

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