[iamjosh]

I modified my Carrera pit lane entry to include the fuel sensor from the pit lane adapter. I did this for two reasons - one, because I use Smartrace for my RMS which requires the fuel sensor track for refueling and two, because I am conserving space on my layout.

It was very straightforward, since the fuel sensor chip simply taps into the power from the track. You just need to remove the back cover on the track to take it out. It is simply pressure fit with no screws.

The pit lane entry track has enough space to fit the chip and sensor.

I decided to locate the hole for the sensor as close to the end of the track as possible...more on this position later. The hole is made with a 7/64 drill bit.

Chip fits well and I secured it with hot glue.

I placed the sensor 5mm from the rail, which is the standard placement of sensors on straight track. After running some test laps, I realized I had neglected to take into account that the car would still be traveling at an angle at this point, so I needed to adjust the sensor location after initial tests.

What's a second hole among friends? The new hole is 10mm from the rail and worked perfectly when the cars were at speed entering pit lane.

I kept in mind that I plan to change my layout in the future, so I sealed it up with electrical tape to keep it clean. The modification is not permanent and can easily be swapped back into the fuel adapter track later.

You can see the sensor on the left by the #4 car's front end.

Refueling in Smartrace in action! Last night, I ran a few test laps to make sure it worked. Success! Today I ran about 150 laps, refueling 6 times with no failures.

 

[MrFlippant]

Is this with traction magnets in place? If/when you remove them, this placement may no longer be reliable.

 

[iamjosh]

Yes, we mostly race with magnets. I have a few cars without magnets that I'll test out soon.

 

[iamjosh]

Is this with traction magnets in place? If/when you remove them, this placement may no longer be reliable.

Of course, you are correct. If I take the pit entry too fast with the faster cars and the no-mag cars, there is the potential for missing the sensor.

I'm debating how much I care about this at the moment. It's kind of a built in penalty for speeding into the pit.

And we mostly drive with magnets. I'm the only one that doesn't and it's usually by myself when I drive those cars.

 

[MrFlippant]

With or without magnets, in the heat of battle (race) it will happen enough times that more than one person will get frustrated by it.

The main problem is that your placement RELIES on a specific angle for the cars you've tried. Longer or shorter cars will be at a different offset. It might not matter, of course, but the speed will matter. Slower or faster.

The best option, if possible, is to have it so that the racers, knowing their car is straight as it passes over the sensor, need only worry about the actual speed limit of the fuel sensors, which I believe is 50% throttle, and not how fast they might be traveling as they cross over that sensor.

That said, sometimes choices are made and the ramifications are simply dealt with.

 

[iamjosh]

I suppose something like this may work better with the pit electronics getting grafted into the chicane sections where the entry angle is not as sharp.

What would be really great is a series of sensors or a bar sensor with a wide angle for detection. That would provide a ton of flexibility in placement and car position as it passes over the sensor.

 

[MrFlippant]

Yes. A row of sensors next to each other would provide the most reliability. It has been done for other things, and is not hard to do, but I'm not an electronics person to tell you how.