Communications with mobile phone

Discussion in 'Wireless & RF Design' started by harishmakke, Jun 24, 2014.

  1. harishmakke

    Thread Starter New Member

    Jun 24, 2014
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    1.) I want to build a circuit which should send pressure details to a mobile phone app. What are ways of communication with mobile?

    2.) Should all the circuits which are to communicate with mobile phones should use rechargeable batteries or are there any long-lasting batteries that can be used for 3 years in one stretch.?

    3.) What is the typical battery to be used for a typical bluetooth circuit?
     
  2. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Do you want wireless communication? If not a requirement, USB communications may be a possibility. Otherwise, WiFi or Bluetooth can be used to communicate. Disclaimer: I haven't done this, but have worked with someone to produce an app to communicate between an iPhone and PC via WiFi.

    What is sending the pressure data? Is this a custom app you are writing? Same question for the mobile app?
     
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  3. harishmakke

    Thread Starter New Member

    Jun 24, 2014
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    Thanks for the reply..Pressure sensor circuit is communicating with the mobile. I want to know what is the way of communication whether it is RF, or Bluetooth or Infrared or in any other way? My constraint is that I don't replace the battery in the pressure sensor circuit for 3 years and so while communicating my circuit shouldn't consume much battery..
     
  4. BR-549

    Well-Known Member

    Sep 22, 2013
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    We need more than that. What Exactly are you measuring? Where is the sensor located physically? How hot is it? Is it inside or outside? Is it exposed to rain? Need the whole story. Might be able to power sensor with small solar panel.......or depending on environment....another power source.
     
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  5. djsfantasi

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    Yes, but is the pressure sensitive circuit built or a commercial product? For illustrative purposes only let's assume Bluetooth is your only option. What programming would you have to do?
     
  6. sirch2

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    Jan 21, 2013
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    And how often are you intending reading the pressure sensor?
     
  7. harishmakke

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    Jun 24, 2014
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    I want to make it for a commercial product. I have a tiny chamber being heated from outside and have to sense the pressure in it and send it to a mobile app..This is my application. Lets assume that the temperature inside the chamber is not more than 40C. I want to build a circuit and drop it in the chamber. The circuit has a pressure sensor and this sensor senses the pressure inside and send to a module on the circuit which communicate with a mobile. My mobile takes the input from the module and show it on n app. This is the objective. I have a serious cost constraint here, so can't go for rechargeable batteries for the circuit will depend only on CR2032, but I should be able to run the circuit for 3 years without changing the battery. So, looking for a communication module in the circuit that consumes ultra low power.
     
  8. sirch2

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    Jan 21, 2013
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    You still haven't really answered some of the questions above.
    What is the camber made out of?
    How far away is your mobile phone?
    How often do you need to read the pressure?

    You can reduce power by having low radiated power (short range comms such as bluetooth) and by reducing how often you transmit (once per second uses 3600 times as much power as once per hour).

    If this is a commercial product what is the cost constraint? Why can't you drill the chamber and fit a wired pressure sensor?
     
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  9. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    From your description, you will have to program both ends of the communication: the sensor device and the mobile device. (Answering my own question; is this correct?) The communications protocol you use is entirely dependent on the infrastructure available. If both devices have a common wireless network available, then WiFi could be used. Bluetooth is a likely candidate (and one I would research first).

    Sirch2 has some very good points. The battery life is dependent on how often readins are required. You haven't provided enough information to determine if you can get three years, but IMHO it will be difficult.

    Also, since you indicate that your module will be placed in an enclosed chamber, that precludes using IR communication.
     
    Last edited: Jun 25, 2014
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  10. harishmakke

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    Jun 24, 2014
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    Thanks for the reply. I'll elaborate on my requirements. My mobile is an android based smart phone. It has both wi-fi and Bluetooth functionality. I want to read the pressure, utmost 10 times a day. Mobile would be very near to the chamber, in the range of 5-10 meters. Yes bro, I have a cost constraint and it makes me go for cheap battery, but battery should lasts long. As I told you, frequency of circuit communicating with the mobile is not more than 10 times a day, even lesser than that. But my battery should last for 3 years. This is for an experimental purpose. I being a mechanical engineer is finding it hard to proceed in this electronics part.
     
  11. harishmakke

    Thread Starter New Member

    Jun 24, 2014
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    Is the widely available CR-2032 battery can be used in a bluetooth communication circuit?
     
    Last edited: Jun 25, 2014
  12. sirch2

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    Jan 21, 2013
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    You still haven't told us what the chamber is made out of? (if it's metal then you may struggle to get a radio signal through it) or whether you can drill the chamber?

    Anyway a quick Google suggests that bluetooth with a low data rate and low sniff rate will use about 2mW. A CR2032 is about 200mAH at 3V = 600mWH so you might expect 300 hours at the very most from a CR2032. And that does not account for driving the pressure sensor or running whatever reads the sensor and drives the bluetooth module.
     
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  13. harishmakke

    Thread Starter New Member

    Jun 24, 2014
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    The chamber is made of plastic with metal bottom. I want the battery to drive the sensor too, the sensor is just a small pressure chip.
     
  14. harishmakke

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    Jun 24, 2014
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    @sirch 2..if u r online may i request u spare some time 10 mins giving some guidance on my project?
     
  15. BR-549

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    Sep 22, 2013
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    Ok guys....this guy is trying to make some money. Which is fine.....but I don't think he is going to give us enough info. He's afraid someone is going to steel his idea. Good luck....I'm outa here.
     
  16. harishmakke

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    Jun 24, 2014
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    Bro, You got me wrong. I'm afraid that I seem to be hiding something. I think I have given everything that I know, I'm very poor at electronics, being a mechanical guy. I have given my requirement that I have to measure a pressure in a chamber 7 times a day continuously for 3 years and the data to be stored in a mobile. I want to build a circuit which i can drop in the chamber, the chamber is made of plastic. I can't change my battery for 3 years. if you might want to know the purpose of the experiment, you may directly ask for it. This project is part of an experiment to study the specific heat values of various gases. This chamber will be used for a quite a long period of time. I thought it would be difficult to change the batteries everyday or recharge them. I want to make the chamber simple. By the way, making money is far from my intention. Now I want to know the feasibility of the project.
     
  17. BR-549

    Well-Known Member

    Sep 22, 2013
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    Well alright then. What are the min and max temps and pressures? Why do you insist on putting a pressure sensor and power supply and transmitter inside the tank? Why do you have to have 3 yr. battery? Why don't you mount pressure sensor and temp probe inside of tank and run leads thru tank to outside? This way, now and in the future you can power the sensor any way you want. Also, you can store and display the data anyway you want?
     
  18. harishmakke

    Thread Starter New Member

    Jun 24, 2014
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    I want my chamber to be absolutely leak proof, so not preferring to go for wired. And the 3 years time I have given is just an estimation. Once the chamber is made leak proof, i don't want to open the chamber for long time. So, want to have a battery which takes care of power supply for that long. We have not yet designed the chamber and how it should be made leak proof, but our constraint is not to open the chamber once it is made. It has an option only to change the gas through a valve. That is the condition. Min and Max temp are 0-70 C and humidity will be 40-80%.
     
  19. sirch2

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    Jan 21, 2013
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    So if you haven't designed the chamber yet, why not do what everyone else does and mount a pressure sensor through the chamber wall? You're a mechanical guy, surely you can think of ways of making it "leak proof".
     
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