I am a newbie on this hardware stuff. I need help on purchasing the components

Brief description of my project

I need a device that would remotely detect weight or pressure when somebody push on it and send the info to the webserver or websockets. The device could be located up to 300 ft.

After doing some research on it I learned that I need, arduino uno as the device main platform, xbee for wireless communication with the web, xbee shield for the xbee and Force sensitive resistor sensor to detect small weight or pressure.


First am I correct above mentioned components would solve what I am trying to do? If not what am I missing? Anything I mis-stated?

I have learned that there are stuff like xbee explorer, Arduino stackable headers, break-away headers, and breadboard. Do I really need these?

In the future I want to be able do other experiments with the board like use ultrasonic sensor with it or infrared sensor to detect objects. Will I need to buy anything specific to make these sensors compatible with the board or they are all standard?

Basically I want to buy everything I need in one shot. Thank you in advance. Any help will be appreciated.

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  • Shopping questions are explicitly OFF TOPIC on this site. Re-read the guidelines you were supposed to have read when you signed up. – JRE Mar 11 '16 at 17:23
  • @JRE- I apologize, Where do i have to re-direct this question to? – sparks Mar 11 '16 at 17:25

I would rather go with ESP8266. You can program that from the Arduino IDE. You don't need anything else than a programming cable (an USB-UART adapter), and you can connect the force sensor to the analog input with one pullup resistor.

There is a similar idea with one button here: https://www.hackster.io/noelportugal/esp8266-ifttt-easy-button-888a87

You can build your own force sensor: http://www.todayifoundout.com/index.php/2010/01/how-to-make-a-ridiculously-cheap-analog-pressure-sensor/

If you don't really need to measure the force, there are much easier solutions to detect weight of a person. These give a simple contact once pressed, and can be used like a button (see the first link in my answer). http://learning.media.mit.edu/projects/gogo/documents/making%20sensors.html#Paper and Aluminum foil.

It is not really possible to buy everything as one batch :) I would say you need:

I suggest you to find an ESP8266 based tutorial, Adafruit has a lot of those, and then you'll have an understanding about the tools and components needed.

If you buy some Arduino, consider buying the ones using 32u4 chip, such as Arduino Leonardo or Arduino Micro. The 32u4 chip has more memory, and more performance than the original Arduino Uno, plus it can work as an USB mouse or an USB keyboard too.

For infra (do you mean a PIR which detects humans, or a reflective sensor?) you have quite a lot of possibilities. In case of using ESP8266 directly, check that the sensors work on 3.3V. Some stuff works on 5V, others on 3.3V. You can interface them easily, but this is just another extra thing to cover, so better go with a dedicated 3.3V sensor.

Ultrasonic sensors are coming also in a lot of varieties. Do you need something ridiculously cheap? A sensor with a short range? A sensor with a longer range? I think you have to set up your goal first.

The Leonardo and Uno and Micro boards work both with 5V and 3.3V sensors. Driving these sensors are quite standard, you need to power them with two wires, and have one wire which goes from 0V to 5V (or vice versa) when something is detected. Ultrasonic sensors vary: there are sensors with one analog output, giving a voltage between 0V and 5V propoprtional to the distance. However most of ultrasonic sensors are simple as the ultrasonic principles: they have one input what you drive, and will give one output of the recived echo signal. In this case you have to measure the time elapsed between the drive signal and the echo, which depends on the distance of the object from the sensor.

  • The ATmega32u4 does have some advantages, and the ability to run code directly on the ESP8266 can simplify projects too. However, it might not be a bad idea for a beginner to have an absolutely ordinary Uno/Duemilanove type ATmega328p board on hand in order to be able to use peripheral example code without any changes - as working out what does have to change for other boards can take a little experience. – Chris Stratton Mar 11 '16 at 18:18
  • @Gee Bee Thank you very much. Do you think xbee should work for sending data to the internet(through websocket)? (I don't want to user ethernet because i want it to be wireless and i don't want to use wifi because it consumes lots of power.) – sparks Mar 11 '16 at 18:49
  • I am unsure how do you mean xbee. It is a form factor of various communication products from Digi, see digi.com/lp/xbee Unless you're using xbee wifi, you can't go to the internet with an xbee module alone. These modules are built to form an intellingent internal wireless network, but require a sort of a concentrator or network hub which has a wifi or ethernet connection if you want to go to the Internet. – Gee Bee Mar 11 '16 at 18:57
  • You may not wish to rule out wifi just "because it consumes a lot of power". Any technology will consume a lot of power. The trick is to keep the communication interval at a minimum. In your case, the device can do nothing, and stay in deep sleep consuming 88uA when no humans are detected. The detection can wake up the module, the module will connect to an access point, send the data, and will consume 200-400mA for 1.5 seconds, then go back to sleep. Average current draw? It runs for 2 days on 2 AA batteries if you don't do sleep. If you do the sleep trick, it can run a year. – Gee Bee Mar 11 '16 at 18:59
  • Oh wow i didn't know that.Thank you very much that was helpful. – sparks Mar 11 '16 at 19:17

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