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1
Short range communication can be implemented in various ways (IR, RFID, BT...). I also could imagine an induction loop, like used for vehicle detection. That loop could be used not only to stop the motor, but also could be used as a rail where the cart can return into its safe harbour. Such a system can be extended into the parking place, if one exists, so that emptied carts can return autonomously.

For further ideas you should describe the cart more detailed, its capabilities and intended use.
2
Français / Re: Quelques renseignements po...
Last post by pagpatrice - Today at 07:42 pm
Je sais bien qu'on peu faire bien plus que deux servos, mais je n'ai pas vu de tel montage encore...des jeux de lumière il n'en manque pas, mais comme tu dis, souvent ce sont juste des variations de lumières et les quelques effet que j'ai trouvé avec des servos sont qu'ils partent d'un point 0 et augmente la rotation en fonction du signal jusqu'à un point défini pour redescendre à l'affaiblissement du signal donc pas super non plus.

Actuellement mon circuit est un pseudo aléatoire basé sur des portes Nand et le PWM est lui en fonction du la puissance du signal mais je souhaiterais supprimer cette platine donc passer 100% arduino.

Pour résumer ce qui est à créer:

1 Détection du BPM ou signal par un micro

2 mouvement des servos

voila pas plus, la lumière elle reste fixe et n'est pas géré, je suis vraiment débutant donc je ne veux pas trop en mettre après pourquoi pas encore plus mais pour un début je ne veux pas trop m'éparpiller dans des choses trop complexe.
3
Deutsch / Re: Problem mit dem Gyrosensor
Last post by flyfly - Today at 07:41 pm
ja paket ist statt data gemeint.
Wie kann ich das Problem beheben?

Gruß
flyfly
4
Line 20, character 16 thank you, now the main problem:

C:\Users\Steve\Documents\Arduino\libraries\ESP8266WiFi\src\CertStoreSDBearSSL.cpp:20:16: fatal error: SD.h: No such file or directory
 #include <SD.h>
                ^
compilation terminated.

5
Deutsch / Re: 7segmentanzeige mit millis...
Last post by timrich01 - Today at 07:38 pm
p9 und p10 gehen direkt zu den digital pins 9 und 10 , die widerstände sind 47ohm.
Der Sketch mit delay ist schon angehängt.
Mit freundlichen Grüßen
Timrich
6
Project Guidance / Re: How would you build a long...
Last post by JCSB - Today at 07:34 pm
Ok sorry for not answering sooner! So, as you guys have seen, La Romaine is a big project. I am not on the dam building team however. we are scientists sampling and monitoring water quality as dams are being built. The team requires to sample at the target location you saw on the map, for a few days, and the wind is ofter too strong for boat navigation. The point of the windsensor project is to tell us before we get there if we wont be able to use the boat. We then need the device to run for 12 days on the battery. Its not actually made for sampling, really for efficiency. The dam company doesnt have precise windspeed at the location we are interested in, and if it does, it is unable to send the information every morning before we leave! For the 12 days, if the device can tell us the windspeed next to the entrance we use for the boat 2 or 3 times every morning, it is perfect for its purpose
7
Thanks! that what I needed
8
Thanks for all the replies!

Quote
So what happens when somebody has triggered the first timer but not yet reached the second? time1 is greater than zero and time2 is zero.  So ((time1 - time2) > 0) is true and it decrements the counter, setting time1 back to zero.
Quote
You are calling CountPeople before you know both time1 and time2 have been set - if only one has been set then you'll compare it to zero and get a false result.
That was a good hint. Thanks a lot. I have adopted the code accordingly (see below)


Quote
With ultrasonic distance sensors, you will get a lot more useful data than basic beam-break sensors.
I considered using beam-break sensors but I am trying to avoid installing electronics on both sides of the doorway.


Quote
You are going to have to do a lot more decision-making with the ultrasonic data. Like detect how fast the person is moving when they hit sensor 1 (how round their belly is) and check that sensor2 sees a similar speed.
I know I have a lot more possibilities with an ultrasonic sensor but do I have to use them? I am not interested in the speed/ location etc. of a person. All I want to know is: Has a person passed both sensors and if yes from which direction?


Quote
How wide is the doorway? Can more than one person get through at the same time? If so, then it's going to be difficult to get a reliable occupancy figure.
It's a standard (European) doorway. Approximately 80cm (31,5") wide. If you try hard to walk through the door side by side with an other person that's probably possible. Anyhow, this is a situation I do not expect to happen.


Quote
One option would be to have small PIR sensors (or beam break sensors) each side of the door so that they cannot interfere with each other and then see what order they trigger in.
I have considered using two PIR sensors but because of the size I decided to go with the ultrasonic ones. Or is there an advantage of PIR over ultrasonic for this purpose?
In case of interference problems I thought about installing the two sensors in an angle and make them point towards the room / floor. In this case I could also measure the distance to the person and use this value to help detecting if a person is entering or exiting. But for aesthetic reasons I am trying to set everything up as compact(/flat) and centralized as possible.

This are the changes I did to the code:

1. I wrote a function to detect if a something has passed both sensors:
Code: [Select]
void PassControll()
{
  if (time1 != 0 && time2 != 0)
  {
    pass = true;
  }
  else if (time1 == 0 && time2 != 0)
  {
    pass = false;
  }
  else if (time1 != 0 && time2 == 0)
  {
    pass = false;
  }
    else if (time1 == 0 && time2 == 0)
  {
    pass = false;
  }
}


2. I modified the Count Function in a way that it only counts in case someone has passed both sensors
Code: [Select]
void CountPeople()
{
 if (pass = true)
 {   
     if (((time1 - time2) < 0))
     {
       people ++;
       time1 = 0;
       time2 = 0;
     }
     else if (((time1 - time2) > 0))
    {
      people --;
      time1 = 0;
      time2 = 0;
    }
 }
 else if (pass = false)
 {
 }
}


My program is still not working probably. I get a reaction every time something passes one(!) sensor. And the display is showing hexadecimal numbers (I guess?). Has anyone an other hint for me?

Additionally I came up with the following scenario which would cause an error:
Person wants to enter the room. Passes sensor #1, changes mind and leaves without triggering sensor #2. Some time later other person wants to exit the room. Passes sensor #2, changes mind and stays inside without triggering sensor #1. Now both sensors have been triggered and the counter will count +1.
I think this problem can be solved by setting both time variables back to zero when the second sensor has not been triggered within 15sec after the initial triggering. I will integrate the according code once the current code is working.

I also plan to add a button to the system for easy correction of the number.

Regrads,
Chris



9
Motor torque is proportional to winding current. So to get 50 in-lb torque from that motor, you need 50*2.8A/130 = 1.1 A.

Most of the inexpensive, modern, current limiting stepper motor drivers can handle that current. My recommendation of the MP6500 in reply #2 stands.
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