7

I'm a web developer - so IoT is not my speciality at all - and I've been asked to find the cheapest and most efficient way (in this order of priority) to build a gizmo for a sport event (can't be more specific). This is how it should work :

  1. A Competitor wear a wristband carrying his unique ID.
  2. At one place there is a terminal which will scan the wristband once in contact, so organizers will know at what time the competitor arrived to this terminal via a web app.
  3. The Competitor must stay 3secs at the terminal and can't just extend arms forward, they must be at the terminal.
  4. The Competitor is acknowledged that his wristband has been successfully scanned and can now move to the next terminal. And so on

So my question is, what should I use for the wristband and the terminal knowing that the bracelets are throwaways ?

EDIT - More details :

  • Competitors can't have their phone nor any device with them during the event.
  • There will be between 40 and 50 terminals max
  • I've been asked for the cheapest solution but I don't have a min/max cost and I'm not limited by dev time (must be reasonable though)
AdrienXL
  • 181
  • 6

1 Answers1

7

How far away from your base computer do the terminals need to be? Does it need to be a relatively real-time system or can the check-ins be cached for a few seconds?

If you could get away with the range of wifi, and the potential latency of an mqtt message (a good protocol if you need QOS) I think an esp8266 microcontroller with one of the these RFID readers would be a nearly ideal setup.

(I personally have a couple of wemos D1 mini's *note this is not the cheapest they can be found, but I try not to promote knock off's)

I've primarily used the NodeMCU firmware, but there's no baked in library for pn532 RFID chips, so you'd have to read/write i2c/spi registers manually. Adafruit has a library for the Arduino IDE, but it only works with i2c (seems under-tested / under-developed for the esp8266)

One of the benefits of a setup like this is that you could quite easily make these battery powered with a usb battery bank (watch out because some turn off if they don't sense enough current draw).

If I were to build these with parts from aliexpress (super cheap) this would be my shopping list:

Then for deployment, you'd need some sort of decent wifi access point that can handle a bunch of lightweight connections (some have a cap on # of connections) and probably a laptop running the mqtt host and your web app server.

Aaron
  • 186
  • 3