Rallycross start and finish triggers.

Our last rallycross had 53 drivers. We did all the timing with stopwatches. It sucked. Our next rallycross is looking to be as big.

The timing crew wants to use the autocross computer system to do timing, but there are numerous concerns about the trigger beams and the dust.

One of the guys came up with a trigger system using hoses with pneumatic switches. Building those isn't a problem. The problem comes in with getting the hoses to work with the Farmtech transmitter/receiver system.

I don't suppose any of you gents or ladies have tackled this problem before. I'm not super familiar with the Farmtech stuff, but I would love to be able to plug the hose system into a Farmtech transmitter and not have to string out several 100 feet of wire. It doesn't look like Farmtech makes anything like that, but we do have a call into them.

Any thoughts if they come back with nothing? Any other options for a wireless system that would work?

Thanks.

Not familar with their system, but I've built the air hose system, and they are generally reliable. Does Farmtek just required a closed circuit? If so, you can just use air switches to complete a circuit, like we do with our wired system?

Or does it need more than that?

It looks like the Farmtech system is a box with the beam and transmitter built in. No other inputs are available. I'm hoping to add a tap to the board that the air switch can close, and have it send to the receiver. It's not looking too hopeful.

I guess worst case, I'll have to rig up a couple of Linear transmitters and receivers to take over the wireless duties.

Unless they have some way to electrically stimulate the wireless sender or to spoof the wireless signal, I think you'd either have to take the thing apart and try to find where and how the current flows from whatever photocell they use and tap in to that or put a battery in the box and use the signal from the air tube to activate a solenoid that would break the beam for you.

It looks like they sell wireless hand-triggers that are compatible with the system. You could crack one of those open and replace the switch with the output from the air sensor probably.

Or, since it looks like they built those for use in equestrian events, maybe they'd be okay with the dust.

We found that the optical systems don't work in the dust. We're using some sort of pneumatic trigger, but we're also stringing hundreds of feet of wire out.

I've been to a couple that use the optical system, and they don't work worth a damn in the dust.

We use a pneumatic setup at ours and it has been trouble-free, other than last weekend when a really low RX7's cat heat shield was hanging own and slit the start hose :/

My first thought is to go ahead and give in and run a wired system. My second thought is to add a layer of complication, is put together something that will trigger the optical sensor when the hose is run over.

Ours involves some kind of mercury switch, now that I'm thinking about it. They're no longer available, and I think we bought 2-3 sets to have backups.

At what height are the optical sensors mounted? If they are low to the ground, can you mount them up higher? Maybe that would help dust from interfering as much.

Just spitballing here.

How dusty are we talking about? Any idea how long it takes to clear between cars?

We used the Farmtech system for the national challenge in a dusty location last year (Frostburg). Depending on how dusty it is they can work ok. They were good at getting start and finish trips the problem was we had a few cars that would almost always double trip the sensors because of dust hanging. If you want to try the Farmtech system I would talk with Farmtech about making the Electric Eye Ignore Period longer (standard is 2 seconds) this is something they say they can walk you thru doing over the phone. The national staff was going to talk with Farmtech after our event last year about doing that for their rallyx events. We rarely if ever got a triple trip and never a quad trip from a single car so something in the range of 4-5 seconds would likely work much better than the standard 2 second lockout but you need to make sure you don't have cars that will be finishing that close together also.

I love that regions across the country are now seeing 50+ car fields, back in 05 a 50 car field only occurred for national challenge events.

Locally, we are switching from hand timing to lasers this spring. Someone did some research and putting a piece of pvc pipe around the laser/mirror is supposed to help.

In reply to moxnix:

The dust at the last event was excessive to the point that I was wearing a dust mask while driving.

Watching several launches on video, it would be 15-20 seconds before the dust cleared.

I bet I could use Farmtech's push button transmitter. I hope to get in touch with them today.

For those of you stating optical systems suck for rallycross, were the problems with the newer style optical sensors, such as this? I've been running these for nearly two years and haven't experienced ANY issues, even with events that were incredibly dusty (had to space out drivers by more than 30 seconds to allow the second driver to see anything).

FooBag wrote: For those of you stating optical systems suck for rallycross, were the problems with the newer style optical sensors, such as this? I've been running these for nearly two years and haven't experienced ANY issues, even with events that were incredibly dusty (had to space out drivers by more than 30 seconds to allow the second driver to see anything).

That is the same farmtek system that nationals uses that I talked about above. For the most part it worked fine but the hanging dust at our site or something would trip the beams again on some cars right after the lockout ended.

This is the dust we are going to be dealing with.

https://www.youtube.com/embed/UkxGaAchB_8

It's not so bad at the beginning, but as the run groups progress, it get to be extremely thick.

We used to use optical triggers in conditions like that and it always devolved to manual trigger. The fun is when the cloud that follows a car trips the finish beam again.

Or when someone would inevitably take out one of the boxes and you had to spend forever resetting everything.

Update. Problem solved.

Farmtek will happily sell you a transmitter with two wires hanging out. A normally open, dry contact triggers it to transmit to the base station.

There are two on the way.

In reply to Toyman01:

Thanks for posting the resolution. I am shopping new timing systems now and something wireless to use with our existing hose triggers would be ideal.

Hose triggers built and ready to go.

They coil up nicely and store it 5 gallon buckets.

The buckets should also keep the pneumatic switches relatively dry and dust free. The Farmtek transmitters should come in tomorrow and will stick right to the top of the buckets.

Yesterday was our first ever Rallycross Points event.

The good news is we pulled in 32 drivers. From what we have been told, that's a good turnout. The venue was happy, we were happy, everyone had a great time.

The bad news is the timing system was a nightmare. False triggers, missed triggers, the entire system was unstable. We chased problems all day. At first we though the pneumatic system wasn't working. It would work if you stomped it, but not if a car crossed it at speed. I made some adjustments to the switches. Then we thought we had a range problem, so we mounted the transmitter antennas on top of 8' tripods. Still problems. We finally abandoned the whole mess and tripped the computers manually. What a PAIN!.

Apparently the pneumatic triggers don't activate the Farmtec transmitter long enough, for it to consistently transmit to the base. A car only closes the switch for a split second. That's not enough time for the transmitter to reliably send a signal. Start would occasionally fail, but finish would fail 60% of the time. Farmtec says they can send us a firmware update for the transmitters that will solve the problem.

I'll update this when we test it.

Our next event is early next month, and the SCCA is giving us the first ever Starting Line school for Rallycross, so we are pretty excited about that as well. It should give us a boost for getting this program off the ground.

Good to know, hopefully it works after the update. I'll have to talk to them when I receive ours.

In reply to EvanB:

The guy we are dealing with at Farmtec is Mike. He's out of the office today, but is supposed to be calling us back tomorrow. I'll let you know what he says.

Oh, and after over 200 runs, the hoses look practically new. I was impressed with how durable the stuff was.

Toyman01 wrote: In reply to EvanB: The guy we are dealing with at Farmtec is Mike. He's out of the office today, but is supposed to be calling us back tomorrow. I'll let you know what he says.

That's who I talked to before ordering them to make sure they would work.