Busy Sunday with Sparkfun's nRf52832 Dev Board

My Sunday(Oct 21, 2018) has been so so so busy because of my beacon experiment. Actually for 2 weeks now, I was stuck at why my battery charge level monitoring circuit would not work(I was just toggling between the board's A4 and A5 analog pins). And I gave up on it and went on to do another task to make the piezo speaker work with the board. I faced another very challenging task why it does not work with digital pin 10, then I remembered previously when experimented with the LED on/off sketch and I used digital pin 15 and it worked, so I transferred the connection to that pin and it worked very well. Because of this I realized that maybe the analog pins A4 and A5 are made for a different purpose so I tried to experiment with A6 and finally, I am getting good results. So, I am able to make both work.

With this success, I prepared a simple sketch that will broadcast Ibeacon, will communicate with the pc to continuously transmit battery charge level(2V up tp 4.2V)  and add GATT Services to get the battery charge level and be able to turn on / off the piezo speaker. So sad that the nRF52832 Dev Board is not compatible with Arduino's Tone library, I am not able to upload the Super Mario Brothers theme music into it.

Creating the program(sketch) is the most critical part because the battery life depends on it, so the sketch must be highly optimized to save power and battery will at least last longer than 1 day. The sketch I created is not the best solution, there are better ways to do it to make it conserve energy and the 800mAH battery could last longer than 3 months. The piezo speaker can consume more than 50mA alone, while connecting to the device would consume 30mAnot to mention the builtin voltage regulator has a normal current leakage of 10 mA and of course the red LED connected to the power source normall consumes 16-18 mA(but this can be disconnected easily as sparkfun provided the connection at the back), at normal operation it(the nRf52832 ic alone) normally consumes around 7mA. I heard that other sketches can lower the normal consumption to 0.3mA or even down to 1microA that should be enough to make it last for several days by putting the device at deep sleep. The sketch I created would only let the device enter the low power mode. I have not tried to make it enter into deep sleep mode because the last time I tried it, the nRF connect app could not connect to it. Maybe there is a technique to make it not to interfere with the connection process.

To be honest, the connection is very stable, it does not disconnect making it ideal as a key finder.

Here is the hardware setup:

My actual device on a breadboard:

With this current configuration, I can charge the battery while programming it. 

Sample Serial Output:

The nRF Connect App Screen:

Here is the screen recording:(you can hear the actual beeping of the beacon:

And finally the sketch:
You may download the sketch here.

Key Fields or Index Fields in a Data Base Table

Key Fields or Index Fields are quite useful in a database table. They were meant to have permanent or fixed values throughout their record lifetime not until the record is deleted. Key Fields makes sure that every record unique. Aside from this the database is equipped with logic(search algorithm) which makes use of index fields to perform fast and efficient search and sorting functions. I remember at one point in my programmer career when still software I am supporting is still struggling to make a name in he industry, one of the the client's problem was the program was running extremely slow so I investigated and found out that several select statements were not using index fields in there search parameter. I am aware that the software is capable of creating customized indexes so I created customized indexes and the result was 80% faster.

With this basic idea of database concepts, programmers will be able to create a group of tables that are optimized in terms query and sorting speeds. It is a fundamental concept that should not be forgotten. Always remember that if a field is meant to be modified, do not use as index field. It is a mortal sin to do it. Everybody will lough at you.

What happens when it is unavoidable because there is a possibility that all key fields are the same except that modifiable field? The answer is record will not be saved in the database. That's when a serial number as key field will come to the rescue. It makes sure that every record entered in the table is unique. It is just a design tip.

Just expressing my thought, duhhh!!!

Make Sparkfun's nrf52832 IOT Board an Ibeacon

Like I said, the nrf52832 breakout board can be programmed to become an Ibeacon using the blepheripheral library, in fact it has a sample sketch. But I think the sample sketch is not applicable to what I am trying to achieve so, I decided not to use the sample sketch. The main reason is that it needs an interrupt and a timer just to change the frame from ibeacon to eddystone, so it is not good.

But, using the included ibeacon library as guide, it enabled me to understand how to turn the device into ibeacon. I used Ibeacon Detector app to capture the data packets or advertising packets, and used the captured data to change the blepheripheral manufurerdata and that's it. I just turned it into ibeacon.

Here is the sample ibeacon advertising packet:

This is the manufacturerdata I used:
0x4c, 0x00, 0x02, 0x15, 0xa1, 0x96, 0xc8, 0x76, 0xde, 0x8c, 0x4c, 0x47, 0xab, 0x5a, 0xd7, 0xaf, 0xd5, 0xae, 0x71, 0x27, 0x00, 0x12, 0x00, 0x25, 0xcb, 0x5c

The breakdown is as follows:
0x4c 0x00 = Apple Company
0x02 0x15 = Ibeacon Identifier
0xa1 0x96 0xc8 0x76 0xde 0x8c 0x4c 0x47 0xab 0x5a 0xd7 0xaf 0xd5 0xae 0x71 0x27 =UUID
0x00 0x12 = Major
0x00 0x25 = Minor
0xcb 0x5c = Transmitted Power(-53dBm)

Here is the complete sketch:

#include <SPI.h>

#include <BLEPeripheral.h>

const char * localName  = "LED On"; 

BLEPeripheral blePeriph();

void setup() {

  // put your setup code here, to run once:

Serial.begin(115200);

  blePeriph.setDeviceName(localName);

  blePeriph.setLocalName(localName);

  blePeriph.setTxPower(measuredPower);

  const unsigned char  manufacturerData[26] = {0x4c, 0x00, 0x02, 0x15, 0xa1, 0x96, 0xc8, 0x76, 0xde, 0x8c, 0x4c, 0x47, 0xab, 0x5a, 0xd7, 0xaf, 0xd5, 0xae, 0x71, 0x27, 0x00, 0x12, 0x00, 0x25, 0xcb, 0x5c};

  unsigned int lng         = 26;

  blePeriph.setManufacturerData(manufacturerData, lng);

  blePeriph.begin();

  

}

void loop() {

  // put your main code here, to run repeatedly:

 blePeriph.poll();

}

Changing the Local Name of Sparkfun's nrf52832 IOT Board

I had been playing with Sparkfun's nrf52832 IOT Board(there is no Chinese spoof version yet and I guess there will never be) ever since I found the IB003N-SHT to be defective. My goal is to develop a firmware using Arduino IDE to make the board function as Ibeacon/Eddystone and at the same be able to advertise sensor data in a different frame. I am still familiarizing my self how to make things done and am currently trying make a prototype whether it is possible to change beacon parameters without hard-resetting the device.

I have so far succeeded. My initial test was to change the local name which a very common function and I have not made it to function as a beacon. I am taking it 1 step at a time. I used the sample program provided by Sparkfun on their website which is the Ble Blink Example. I added the following features:

1. Added a new Service to change the local name
2. Added a characteristics under the new Service
3. When the value on the said characteristic change, it will change the local name and reset the BLE.

The logic is very much the same as the original program when turning on/off the LED connected at pin 7. And here is the source code :

// Import libraries (BLEPeripheral depends on SPI)

#include <SPI.h>

#include <BLEPeripheral.h>

//////////////

// Hardware //

//////////////

#define LED_PIN    7 // LED on pin 7

#define LED_ACTIVE LOW // Pin 7 LED is active low

#define LED_DEFAULT LOW

///////////////////////

// BLE Advertisments //

///////////////////////

const char * localName = "LED Off"; //change the local name

BLEPeripheral blePeriph;

BLEService bleServ("1207");

BLEService chgName("1208");//added new service

BLECharCharacteristic ledChar("1207", BLERead | BLEWrite);

BLECharCharacteristic chgChar("1208", BLERead | BLEWrite);//added new characteristics

int vb =0;

void setup() 

{

  Serial.begin(115200); // Set up serial at 115200 baud

  pinMode(LED_PIN, OUTPUT);

  digitalWrite(LED_PIN, !LED_ACTIVE);

  setupBLE();

}

void loop() 

{

  blePeriph.poll();

//--

  if (ledChar.written())

  {

    int ledState = ledChar.value();

     if (ledState) {

      digitalWrite(LED_PIN, LED_ACTIVE);

     } else {

      digitalWrite(LED_PIN, !LED_ACTIVE);

    }

}

//--

//--This my added service when change this is triggered

  if (chgChar.written())

  {

    int chgState = chgChar.value();

    

    if (chgState) {

  

       blePeriph.end();

       setupBLE0();

     

    } else {

     

     blePeriph.end();

     setupBLE1();

    }

}

//--

}

void setupBLE()

{

  // Advertise name and service:

  blePeriph.setDeviceName(localName);

  blePeriph.setLocalName(localName);

  blePeriph.setAdvertisedServiceUuid(bleServ.uuid());

  // Add service

  blePeriph.addAttribute(bleServ);

  // Add characteristic

  blePeriph.addAttribute(ledChar);

  //my New Service and characteristic

  blePeriph.addAttribute(chgName);

  blePeriph.addAttribute(chgChar);

// Now that device6, service, characteristic are set up,

// initialize BLE:

  blePeriph.begin();

// Set led characteristic to default value:

  ledChar.setValue(!LED_ACTIVE);  

}

void setupBLE1()

{

 // Advertise name and service:

  blePeriph.setDeviceName("LED Off");

  blePeriph.setLocalName("LED Off");

 // initialize BLE:

  blePeriph.begin();

}

void setupBLE0()

{

  // Advertise name and service:

  blePeriph.setDeviceName(localName);

  blePeriph.setLocalName(localName);

// initialize BLE:

  blePeriph.begin();

}

And here is the video on how it is done(1208 is the new service visible in nRF Connect:

IB003N-SHT Honest Review

Not long ago, I bought this beacons from Alibaba. What attracted me most and main consideration of choosing this beacons against a number of China made beacons are the following:

1. It can broadcast 3 frames(Ibeacon, eddystone(URL or UID) and Accelerometer)
2. It has a specialize temperature sensor
3. It has buzzer

For some reasons, the Chinese seller had delayed the delivery considering that I paid expensive shipping charge($30) but the delivery time took almost a month which is just like having it shipped for free via postal mail(small packets) but I didn't mind it since the product I bought are really loaded with tons features.

Ok the item arrived and my initial testing which is to check whether it really can broadcast the 3 frames and it worked. Days later, when I tried to check the data being broadcasted and verify if it really has all the goodies and to my surprised, I found that it is not what they claimed it be which really had disappointed me. Here are my actual findings:

1. Ibeacon and Temperature Sensor issue. According to their documentation, the temperature readings are being broadcasted at the major and minor (least significant bits). During my test, I could not find the major value and the minor value turns out to be the least significant bit. I reported this issue to the Chinese seller and after a few days of discussion, they have admitted that the major value is unusable. They did not mentioned this in the technical documentation they have provided nor on their advertisement. Another issue I found is that most of the time, the temperature reading is 0 which is weird and I found this to be a hardware defect.
2. Eddystone issue. The data being broadcasted is not Eddystone standard compliant. The main identifer of Eddystone "AAFE" is missing, I have confirmed this because even nRFConnect can not identify the frame as Eddystone. Their counting of UID begins at the "02" byte which is absolutely wrong. The transmittion power is missing. And worst is that when I tried to populate the characteristics "FFD02", the Eddystone frame goes blank which stunned or shocked me.
3. Buzzer Issue. 20dB is very loud, and based on their technical documentaion, it can be adjusted through GATT. But during my testing, the loudness could not be adjusted. With that loudness, I could hardly hear it.

After I found these defects, I stopped the testing of other features. I have already concluded that the IB003N-SHT is full of defects. I tried to negotiate with the Chinese seller by returning the product to them due to the above mentioned defects, but I got this reply from them:

"Our products have no defects, but if you are not satisfied, you may return the items to us. But pls do not include the batteries. We will deduct $2 for each item for the batteries. We will test each items after receiving them from you and we find no defects, we will refund your money. Shipping and delivery charge will be deducted."

I think this is not what I have expected from them, with this transaction, I would suffer $127 loss which way too much.

Reading Temperature and Humidity on AppsFactory Beacons

AppsFactory Beacons have SHT20 High precision Temperature and Humidity sensor embedded in them. Reading the values from the beacons is not that easy that is why this post is written which will serve as guide. Temperature and Humidity is important as it will allow building owners discover patterns that can not be detected by ordinary humans not unless of course humans are so super intelligent that they may not need tools to predict or discover patterns which could suggest something is just about to happen.

There are two ways to read the sensor data which are as follows:

1. can be read via GATT
2. can be included in the beacon advertisement data.

Here is the detail:

1. Reading the Temperature and Humidity via GATT Service

The data can be accessed via GATT Service 0xFFB0 see table below:

The characteristic 0xFFB3 is used to enable the measured Teperature and Humidity on the Advertisement Data. The possible values are as follows(2 bytes):

• 0x0 - Enable
• 0x00 - Disable 

Other values maybe entered to specify the rate which it will be advertised, example if 0x0F was entered means the temp and humidity will be advertised every 30 seconds. 

2. Reading the Temperature and Humidity from Beacon Advertisement Data

The Temperature and Humidity is included at the last bytes of the major and minor of the Ibeacon frame.

After obtaining the value, the conversion formula to get the actual values are as follows:

Beacon Scanner App Updated

Remember the app I created to scan Ibeacons and list them on screen and wrote about it that it is possible to modify the app to scan EddyStones as well? To prove it, I have decided to modify it myself. In case you haven't read the previous posts, here are the links:

A Simple Ibeacon Scanner App in Android

An Update to the Ibeacon Scanner App for Android

The a small change I made is to change the name of device whether it is an Ibeacon or an EddyStone-UID.

Like I said, the file DeviceScanActivity.java needs to be modified to detect the 3 Eddystone frames, but I only modified it to scan the UID frame on for demo purposes. And here is the code I insterted:

This is the raw data taken from Ibeacon Detector App:

And here is the resulting app: