Bluetooth Low Energy Proximity Tag – Reference Design

Complete reference design for Bluetooth Low Energy proximity tag

Bluetooth Low Energy Proximity Tag

Bluetooth Low Energy Proximity Tag

You will never have to search  for your smartphone again. You will never forget your smartphone in the pub. Just locate your key fob by using your smartphone easily. Use your smartphone to locate your wallet. Get security by automatically locking your laptop by distance to your tag.

Functionality of the Bluetooth Low Energy proximity tag

  • Out-of range alert
  • Find tag with mobile phone
  • Find mobile phone with tag
  • Send battery status to mobile phone
  • Locking your laptop automatically, by high distance to tag

On CR2032 coin cell battery offers years of battery life

  • < 15 mA peak
  • < 20 µA connected mode average
  • < 200 µA advertise mode average
  • 0.5 µA Idle mode

Bluetooth Low Energy Proximity block schematic diagram


nRF8002 block diagram

The application is based on a system on chip. Micro controller, memory, oscillators and the I/O channels are on the same integrated circuit. The certificated Bluetooth Low Energy Stack is running on the chip as well. There is just a button, a LED and a buzzer as human machine interface. The bill off material is less than 20 components.
Bluetooth Low Energy is using profiles. Such Bluetooth profiles takes care, that devices from different vendors can talk to each other. We know that already my using or mobile phones. You phone will quickly paired to your hands free kit. This you and me are doing daily automatic by starting the engine of the car. As soon the engine is one the phone is paired with the hands free kit. In Bluetooth Low Energy we have the same kind of algorithm.

The Bluetooth proximity tag is supporting

  • Proximity reporter
  • Find Me Locator
  • Find Me Target
  • Battery reporter

Bluetooth Low Energy FAQ

Is the tag only discoverable by the phone?

The tag will communicate with any Bluetooth Low Energy Master. A master cloud be a smartphone, tablet PC or laptop. I have seen the interaction with a laptop live. The screen saver started after to big distance to the laptop. The laptop was locked. The evaluation kit you will get will emulate the master. That means you can develop your device, test it, approve it and certificate it even we all waiting for the first smartphone that will supprt Bluetooth Low Energy. If the paired piece of hardware is something you developed, then it will communicate too as well.

Do you know if they are available in the US ?

It is available in country. By ordering with me I put my free of charge antenna designs, my long list of 2400 MHz antennas and my 25 years in radio communication on top.

When will be the next Bluetooth Low Energy Seminar?

I am not sure. Anyhow, you can get the copy of the Power Point Presentation of the most speakers at the seminar. List of topics at the seminar:

Our speech was: Smart Home by Smart Phone – Bluetooth Low Energy product family µBlue and alternatives

Frequently Bluetooth Low Energy misunderstanding

Bluetooth Low Energy is not compatible to the old Bluetooth 2.1. Bluetooth is a quite other technology. It saves power because it is always off. It is pushing packages of 32 Byte only. Such a package contains the kind of profile that the used value. Example: Temperature profile and degree in Celsius or Fahrenheit. In Bluetooth Low Energy we have no audio video or data stream. We have star networks only and no meshed network. Bluetooth Low Energy is not using frequency hopping. The radio approvals are like with WIFI.

We would like to start the development of a Bluetooth Low Energy tag and apps. How can you help us ?

After ordering the evaluation kit you will get access to further information and documents. The experience of the last 25 years has shown that it is the best to select antenna and enclosure first. I will accept order for evaluation kits only, if I am 100% sure that your business idea will work well by using my recommended components.

Do you do design work?

Yes I do it with together with long term business partners. A new design start with a questionnaire of mine. Based on the answers I will come back with a recommendation for the hardware and software concept. In this early stage I will take care that you will be able to pass all certificates and world wide approvals. After that I will have a look how in my network has capacity for design left and how fits best to you. Developers with experience can do the job often faster and cheaper. After negotiation with the designer the first step is often a written specification and then a prototype. Two to five specification plus a quick prototype  are often much cheaper than 100 pages upfront. Most time the people forget to specify something. Developing and testing and then optimisation is often the cheapest and the fastest. To make a long story short: You can get from concept up to  approvals and certificates everything from one hand and have always the freedom to make parts of the projects yourself or with other parties. Hardware made and approvals made designer and software by customer is very common.

Do you have further questions and would like to start the development of your own Bluetooth Low Energy app right now?

We will be glad to share our more than 15 years in GSM and GPS plus 25 years in radio communication with you. Just send an e-mail to harald.naumann (at)


Add a Comment
  1. Nice product!

    I was wondering, what will be the range of the tag?
    And what cost price range should i keep in mind?


  2. Hi Mariet, the range you can calculate in theory by using the power level, the gain of the antenna and the sensitivity of the receiver inside the laptop of smartphone. In praxis we talk about meters. To save the battery you will use a low power level. As soon you move away from your desktop the PC or laptop is locked. By using it as a locator of your missed keys or phone (its works bidirectional) you will use the maximum power level. The range depends on the antenna efficiency of the smartphone. Some manufacturers of smartphones have good antenna designers – some others have it not.
    Prices I do not have. Anyhow, it will be not expensive. The whole bill of material contains less a very small number of components.
    Are you looking for a final product or a reference design?

  3. Hi Harald,

    I’m in the process of evaluating an investment into a company doing something similar. Is your product already available / are you available for design work etc. Please send me an email


  4. Hi Tom, yes it is available. A blog is the wrong place to share secrects and details. I will come back with further information by email.

  5. If I am using a smartphone to monitor those Proximity Tag, is there a max. number of tag I can monitor under the closed distance?

  6. Hi Ardy, what will be your application? Please explain more. Maybe the proximity tag feature is the wrong profile. Right now, I am working on to make a table of all profiles and its adaption public. On standard Bluetooth stack you can connect seven devices in same time and 255 – 7 = 248 you can park. I am not 100% sure, but if I am right, then you can connect seven devices in same time. Seven devices means 1 mouse, 1 keyboard, 1 proximity tag and 4 more devices on any other profile you like. If you connect more than one tag to the phone then you get just more events at your software in your phone. The HCI stack of your phone has to handle all events from standard Bluetooth 2.1 and Bluetooth 4.0 (Bluetooth Smart) in same time.

    BTW, as more hardware you connect to your smart phone, as higher will be the power consumption. That means it makes technical no sense to connect too many devices by Bluetooth Smart to your phone.

    Are you sure, that Bluetooth Proximity Profile is the right solution for you?

  7. Hi Harald,

    I thought BT4.0 technology can support unlimited paired at the same time, the only limitation is the bluetooth stack, and I heard the limit is around 700+ pairs? What if I am not using a smart phone, instead I am pairing and monitoring your numbers of Proximity Tags with a PC, is it possible?

  8. Dear Mr. Harald Naumann

    the reference design was already done ? or I have to developing the concept by myself using nRF8002 or nRF8001.

    Can I get more detail information ?

    thanks and regards,

  9. There are several reference designs. The temperature data logger is based on nRF8001 plus some micro controller. The proximity tag is on nRF8002. The nRF8002 is a SOC. On the SOC you can not change the firmware. Anyhow, it is cheap and it has much less power consumptions then other ICs in the market.
    The final answer depents on your application. Without to know it I would like to order the reference for the temperatue data logger and to redesign it to your needs.
    If it is a proximity tag, then my recommendation is the nRF8002.

  10. Hi Ardy you answered the question yourself. Please ask the supplier of your HCI stack. A PC can run on Windows XX, Linux, Android …
    Right know I do not know if BlueZ on Linux s supporting Bluetooth Low Energy. BTW, I need BlueZ as dual mode stack for Bluetooth 2.1 and Bluetooth 4.0.
    I found a dual mode stack for micro controllers in the meantime.

  11. Hi Harald,

    For the proximity tag on nRF8002, can it be detected by normal bluetooth handphone?
    Can you share your design?or what is the price if i buy from you the tag and the design.

  12. Just read this blog post to the end. Then you will see that a standard Bluetooth will not support Bluetooth Smart. The design you get by placing an order for the evaluation kit.

  13. Dear Mr. Harald Naumann

    I need to identify the metal containters whith runs near reader. Standard tags (Mifare ect) doesen`t works because I think there is to big metal mass near tag.

    Is the Bluetooth tags is solution to my problem ? I need a simple reader with Wiegand or (better) 1-Wire output and reader sends over this interface only a serial number of the tag (no additional information is needed). Is the tags are IP67 (the can be damaged with weather).

    thanks and regards,


  14. Hi Harald,

    The specifications of the product tōd “”, the maximum range is 500 feet. Is this possible? as there are other products that say they only support 50 meters. I have doubts, the range that we have with BLE 4.0.

    Thanks and Regds

  15. Stefan, I assume I have a solution. Please note that I have team members in Poland. Please come back by email.

  16. Dear Mr. Harald Naumann,

    We want our company to develop a sort of panic button for taxi driver that communicates with an android smartphone, the tag bluetooth solution can help us?

    I await your return.

    thanks and regards,

    Gustavo M. Castro

  17. Dear Gustavo, yes I can. BTW, I was selling data terminals for taxis a 20 years ago. Maybe we can use my old contacts to generate some sales in Europe. Who shall make the hardware design? You? Me? A partner of mine? Who will write the software for the panic button? You? Me? A partner of mine? Where to produce it? In Germany, Mexico or Brazil? What type of radio approvels you will need?
    Bye for now.
    Best regards from Germany

  18. Are these units still available? If so could you please info me how I might order a few.



  19. Hi Mike, you will get an email with an offer for the tags in version three.

  20. Hello Harald,
    I need an pplication similar to the guy with a panic button for a cab driver. I need you to supply the comlete functional unit. I wiil write the app fro the reciever.
    please Advise on availability. We can have this unit manufactured in Mexico
    Alvaro Ramirez

  21. Hi Harald,

    May I know what are the services that you provide regards to the proximity tag?

    Do we buy the tag from you or the nrf8002 from other place?

    Do you provide an APP for Android or IOS too?

    Please reply to me soon. Thank you.

  22. Hi Tim, you will get an email. I will show you a source for he BLE tags including demo apps for Android and iOS:

  23. Hi Harald,

    I am looking to create a system that turns on a television screen when the user is 2 meters from the television and turns off when not. Can this be done? How? What and where can I purchase such a thing? Thank you.

    Best from Philadelphia, USA

  24. Shane, the off is already done by Sony. The on and off can be done by emulation of the remote control on infrared.

  25. Harald,

    I would like to communicate by email regarding this device for an application we have for tracking items.

  26. Hi Harald

    I am looking for a BTLE Tag which gives the possibility to adapt the SW. Is it possible with the tag above?
    Thanks, Marco

  27. Marco, the BTLE tag was build on a stupid IC were you can not change the code. Nevertheless I will come back to you with a proposal how to design an own intellegent BTLE tag yourself. The evaluation kit including source code costs estimaed Euro 95.

  28. Hi Harald, we are family promotion agency which offer to our customers innovative items – well, whenever possible :o) – which are not only giwe-aways but have their own value. I feel Proximity Tags and similar items might be such an interesting thing we might be succesfull with. I’ve seen many of them on the web. Could you come back to my e-mail, I’d like to have an idea what might be the possibilities of these items ( e.g. in combination with GPS module)and, off course, possibilities of business cooperation.. Thanks a lot! Stepan

  29. Stepan, please email me on harald.naumann (at) . Behind me is a bulk of engineering offices and freelancers. I am just the Field Application Engineer only. If you have an realstic idea, then they make it real. If you have an idea and you are not sure if it is realizable then they can have a look as well. The only you need is a budget.

  30. Hi Stephan,

    My name is Henrik and I am researching the use of such a device in the health care industry. I do not want to leave more information here and wonder if you could get back to me via email?

    Thank You,

  31. Dear Henrik, we are already in contact by email. You got an offer a few minutes ago.

  32. Hallo
    We are looking for Bluetooth LE click button.
    Can you send me items you provide details info?
    Thank you

  33. Dear Giacomo,
    Please have a look at the BLE click button here
    You will find an email in your inbox.

  34. Hello Sir. I am hoping to make a BLE item tracker for my final year project. Which BLE model should I use? Is there a block level schematic diagram available? Also, as my coding is not very good, how much programming is involved in the implementation? Much Thanks.

  35. Malika, I can help with BLE modules with may ready to use code for iBeacon protocol. A final beacon is for example:
    Your self made PCB + BLE module + code for iBeacon + antenna + battery holder + battery + enclosure as a 3D print

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