Pimentoso/mini4wdchrono

Mini4wd Chrono building help

Opened this issue · 12 comments

Hi Michele
I'm attempting a build of the mini4wd chrono for our local club and I have
some questions. I have some basic understanding of electronics, but I need
clarification on the wiring diagram.

  1. please confirm - resistors on the green LEDs are 220 ohm

  2. the Photo sensor TEMT6000 has 3 connections. In the photos I can see 3
    wires going to it, but on the circuit diagram there are only 2 and it does
    not say where to connect them - OUT, GND or VCC

  3. is the resistor for the photo sensor 10K ohm? Is that right for the
    TEMT6000 and which of the 3 connections is it connected to?

  4. what are the green LEDs for? I can't see reference to them in the
    documentation. Do they turn on to start the race?

  5. I've got the laser diodes. I guess that these are powered the whole
    time. Can I plug these straight into the 5v power pin on the arduino? Do
    I need any resistors inline with these?

thanks for your help.

We're excited to have this running for our races.

thanks

Mark (from New Zealand)

On Sun, 12 Jan 2020 at 03:36, Michele Ferri notifications@github.com
wrote:

Closed #44 #44.


You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub
#44,
or unsubscribe
https://github.com/notifications/unsubscribe-auth/AKHJUZYIJKVSRY6JIJK5NBLQ5HKPXANCNFSM4KFEXDZQ
.

Originally posted by @markinNZ in #44 (comment)

Hi Mark,
yeah the photos are a bit outdated and I haven't managed to take new ones. The wiring diagram is also outdated because it doesn't account for TEMT6000 sensors.

  1. I usually buy lilypad LEDs which have the resistor already included but yeah, usually you'll need a 200/220 ohm resistor for each LED.
  2. you should connect the VCC to the 5V output of the arduino, the GND to the GND, and the OUT pins to the digital pins 3,4, and 5 of the arduino.
  3. you don't need resistors on the sensors if you use TEMT6000, they bundle everything.
  4. yeah the green leds flash at the beginning of the race, and are lit when a car passes under the lane.
  5. indeed they should be wired directly to the 5V along with the sensors VCC end.

I'll try to update the diagrams and the electronic pictures in the coming weeks. I'll move this to a new issue which is not closed so other people can read it!

Definitely let me know. Having feedback from external people is great so I know how to improve the documentation.

So are you saying the sensors report 1 even if the lasers are not pointed to them? That's not normal. What if you pinch them with your fingers to completely cover the sensor?
Check the wiring to the sensors. The VCC of the sensors should be all wired together to the 5V out of the arduino, same for the GND to ground, and the OUT pins should be connected to digital pins 6,7 and 8. Also check in the configuration tab if the pins are configured correctly.

The sensors are connected to the digital pins because of the faster readings. TEMT6000 are phototransistors so they allow for both analog and digital readings. The project uses the javascript "johnny five" library for arduino connection, and after a lot of trial and error I found that in this library the analog readings are much slower, and for mini4wd hitting >10m/s speed in certain tracks we need more than 75 readings per second, and analog couldn't keep up. For this project we don't need analog values anyway, we just need 0 = darkness and 1 = light.

Please let me know if you manage to fix it.

Glad you sorted it out! I'm afraid github eats the attachments though so I can't see the pics.
If you don't use the tournament generator tool you miss half the cool functionalities of the software though.
"Manches" are just how many times each player is supposed to run in the race. So if you add 9 players and choose 6 manches, each manche will have 3 groups of 3 players, repeated 6 times, randomizing the opponents. Please try fiddling with the "generate" function and see if it fits your need.
I can plan to add a checkbox to "force" the program to only generate rounds with 2 lanes.

Hi Michele
We have progress. Seems that all the hardware is working, however I can't get lap times. We're in lockdown so I can only use a small track I have around at the moment. Here are the details.
Lane 1 green light comes on, then off, then lane 2 on then off, then 3, on then off. The Lane 1 green light, followed by 2 and 3. Lights go off. At this point I release three cars from 1 straight before time bridge. Cars not registered, time does not start. Lane 1 car then starts second lap, timer starts for Lane 2. Lanes 1 and 3 go to 99.999. Next lap Lane 1 car (now in lane 3) goes under bridge and timer goes to 99.99.
When running without the timer on, every time a car goes over a sensor the green light comes on, so the cars are being seen by the system.
I tried multiple computers.
Track: ACL2P8
Tournament: ETT823
Version 12.3
Free Round
Time attack mode
Max Start delay: 3
Avg Speed: 5
Lap Threshold: 40.

thanks for your help
Mark

@markinNZ ok some things to check.

  • First, make sure your lane order is the same as shown in the program: 1 is the left lane when starting, 2 is the middle one, 3 is the right one. I had a friend contact me about his times not being registered, and turned out he had the sensor for lane 1 on the right one and viceversa.
  • Second, you're referring to just lights for the starting sequence; do you not have installed a beeper? The cars should be released when you hear the long beep. If you don't have a beeper, the sequence goes like this
    • all 3 lights on for 1.5 sec, long beep, then lights off
    • light 1 on after 1 second, then light 2, then light 3
    • all lights off, then after 1.5 sec all 3 on again and long beep: the 3 second delay timer starts here. Release the cars as soon as all lights are on, if the 3 seconds pass the cars are marked 99.99
  • Third: probably 5m/s are a bit too much for such a short track. Check the data under the "average speed" field: using that track at 5 m/s, the program reports "ESTIMATED ROUND TIME: 5.272 sec" which means the program expects a car to complete the 3 laps approximately in 5 seconds. I can suggest you to start a car and check how many seconds it takes to do the 3 laps (using a wrist watch/cell phone/counting in your head) and then reduce the average speed until the estimated round time is acceptable (click "save settings" and the data will be recalculated)