# Drag Racing

Hi! So the idea is to create something like Drag Racing Light Tree (Christmas tree) and further drag system in real scale. I haven’t practical experience with circuit design and I'm noob in it, therefore I need your advice and make my vector in right direction (links, articles, etc. ).
In nutshell in my town there is a bike drag racing which I want to make more automated and modern. I created a picture for clearly understanding.

As you can see I have 3 clauses phases which will extended with your help to subclauses subphases. (also, can you please check if the links are correct, don't want to buy something wrong)

• clauses phase. I will create this tree with Arduino board which will support bulb-shaper lamp with a bunch of 8 channel relay.

• clauses phase. One guy advised me to use light barrier and after doing a little bit of searching I stumbled upon PIR Motion Sensor.

• additional: also I guess it should have good resolution power for measuring float time numbers and compare between two cyclists.*

• clauses phase. Retrieve all this data and send to back-end part. Yes, I think it would be grate to monitor all data online.

• additional: what about back-end part, that will be more easy for me.*

That’s all, except one, also if it possible it shouldn’t be so expensive, I’m seeking cheap details as I’m a student (:

I started from 2 clause. The problem is, how to recognize two different cyclists (players) at the finish. My crutch is based on buying PIR motion sensor with 360 degree, placed it in the middle of the finish line, then make some business with a code, briefly divide it into two parts for each 180 degrees.

I assume English is not you first language as this post is written most oddly. Your talk of "clauses" is something applied to a legal document not an engineering plan. So when you use the word caluse you should use the word phase.

My crutch is based on buying PIR motion sensor with 360 degree, placed it in the middle of the finish line, then make some business with a code, briefly divide it into two parts for each 180 degrees.

That is simply not going to work, PIR sensors do not work like that and they won't wait until a cyclist crosses the line.
A PIR sensor will not be able to differentiate between a cyclist starting and one gently rocking back and forward on the start line.

also I guess it should have good resolution power for measuring float time numbers

This makes little sense. Resolution is something that references an digitized signal from an analogue sensor. This seems to be nothing to do with your project.

clauses. Will create this tree with Arduino board which will support bulb-shaper lamp with a bunch of 8 channel relay.
clauses. One guys advised me to use light barrier and after doing a little bit of searching I stumbled upon PIR Motion Sensor.
additional: also I guess it should have good resolution power for measuring float time numbers and compare between two cyclists.
clauses. Retrieve all this data and send to back-end part. Yes, I think it would be grate to monitor all data online.
additional: what about back-end part, that will be more easy for me.

1. As you said you gonna use arduino uno and relays, you already got the setup of the lights?

2. If this is a area of the road which is used only for Bicycle Drag Racing you can use a simple 0.50\$ laser and a photo diode to measure the exact moment when the cyclists gonna finish the race and get your data.
You will need 2 lasers and 2 photodiodes.

3. You can use a nRF24L01 to transmit data from the finish line to the start line and save it to a tablet or laptop.
For example :
Race 1:
Bicyclist nr.1 : 1:02:43
Bicyclist nr.2 : 1:01:32

Thanks,
D.60

I haven't made first phase yet, because I decided to start from 2nd. Yes, we have free area for drag racing, it has 200 meters in length and approximately 13 meters in width. As I understand from your suggestion, you want to place 1 laser and 1 photodiode for each person at the finish or at the start and finish respectively? Because if it will be only one laser and photodiode at the finish, the objective of getting clear values become complicated. Also I can't figure out which laser should I use, if like this one, I should have 6M of wires? Or it's better to use something like this

Another one, what to use to tell arduino that green light is turned on the tree and you need to start measure the time & how to tell arduino at the start if someone crossed the line at the finish, I guess wireless RF receiver module would be enough.

what to use to tell arduino that green light is turned on the tree and you need to start measure the time

You are writing the code, so when there is the bit of the code that turns on the green light you start timing from that point.

Because if it will be only one laser and photodiode at the finish, the objective of getting clear values become complicated.

Not complicated, impossible to determine who crosses the line first.

which laser should I use, if like this one,

That is not a laser it is a laser sensor.

Or it's better to use something like this

That is a laser.

I guess wireless RF receiver module would be enough.

Yes that could work, but you would have to test it first.

Grumpy_Mike:
I assume English is not you first language as this post is written most oddly. Your talk of "clauses" is

I wondered if that was a mis translation of CASE.

Boardburner2:
I wondered if that was a mis translation of CASE.

Nope Not even close

Grumpy_Mike:
That is not a laser it is a laser sensor.

Grumpy_Mike:
That is a laser.

So what's the deal? Should I buy laser pointer and set it towards the photodiode?

Boardburner2:
I wondered if that was a mis translation of CASE.

Case implies a specific set of circumstances in a system. Hence the case statements in C.
Clause is a sub section but with no sequential significant like a law consisting of a number of clauses.
Where a phase implies a sequence of operations one after the other. Other words you could use in a project instead of phase would include:-
stage
step
section
part

UYScuti:
My crutch is based on buying PIR motion sensor with 360 degree, placed it in the middle of the finish line, then make some business with a code, briefly divide it into two parts for each 180 degrees.

With a PIR sensor and its about 250 milliseconds reaction time you will most likely not be able to detect which racer finishes first: The one who was PIR-detected 100ms earlier than the other, or the other way round.

If you want to tell who's starting or finishing first you'd need much faster sensors than PIR motion detection sensors.

Any laser really will do. Point it directly at the photodiode, and when it breaks the input will drop significantly. If you want to have sensors at the start and end for both racers, you could start a timer when the start is triggered, and stop when the finish is triggered. If you do this, you will have a precise time, but the racer's reaction times will not play into account. If you turned the light on with the relay, just start the timer after you turn the light on. This is assuming you are controlling the lights via relays on the arduino. I see no need for the arduino to "know" when the light is turned on, as it would be simpler just to turn it on directly. You could wire up a simple pushbutton (or a massive, covered, missile launching style switch) to start the timer and turn on the light.

I haven't made first phase yet, because I decided to start from 2nd. Yes, we have free area for drag racing, it has 200 meters in length and approximately 13 meters in width. As I understand from your suggestion, you want to place 1 laser and 1 photodiode for each person at the finish or at the start and finish respectively? Because if it will be only one laser and photodiode at the finish, the objective of getting clear values become complicated. Also I can't figure out which laser should I use, if like this one, I should have 6M of wires? Or it's better to use something like this

Another one, what to use to tell arduino that green light is turned on the tree and you need to start measure the time & how to tell arduino at the start if someone crossed the line at the finish, I guess wireless RF receiver module would be enough.

Place only one set (photodione and laser pointer) per person at the finish line, you don't need at start line sensor with lasers, the race will start when the light go Green, or countdown lights the last light will start the timer of your race and the finish line lasers will detect when the left or right person finished the race (time).

Starting the timer at the start when turning green light ON it's easy, if you use relay you use a function or part of the code to light up the light as well you can create a variable reading if the light is ON or OFF, if the light go ON then you start the timer.

So let me recap to make it clear for you and others:

1. Use a arduino and relay to light up the light at start line.
2. Use relay green light with a variable in the code to detect if the light is ON or OFF
3. Use the ON or OFF variable to start the start line timer
4. Use 2x set of laser and diode at the end of the race to stop the timer per person and see what's the time they did.
5. Use a wireless module (nRF24L01 PA 2db antenna is a good one for your range) to get back the data from the finish line and restart the timer for the next race.

Thanks,
Domino60