BLE_nRF24L01 - Bluetooth Low Energy (BLE) beacon with nRF24L01(+…

Users » hudakz » Code » BLE_nRF24L01

Zoltan Hudak / Mbed 2 deprecated BLE_nRF24L01

Bluetooth Low Energy (BLE) beacon with nRF24L01(+). Data is received and displayed by Android device (Android app source code is attached).

Dependencies: DS1820 mbed

nRF24L01 as Bluetooth Low Energy (BLE) Broadcaster/Beacon

Temperature measured by a DS1820 sensor is broadcasted by a nRF24L01(+) module as Bluetooth Low Energy signal. Data is then received and displayed on an Android device (smartphone/tablet) with Bluetooth Low Energy (Bluetooth Smart) enabled. In order to have Bluetooth LE available your device should run Android 4.3 or more recent.

Needed parts:

mbed module
nRF24L01 or nRF24L01+ module
DS18B20 or DS18S20 sensor
4.7k Ohm resistor
Wires
Breadboard
Android device with Bluetooth LE enabled (Android 4.3 or more recent)

Zoom in /media/uploads/hudakz/img_20150314_115402.jpg
Figure 1: The hookup and the Android app in action

It was Dmitry Grinberg who figured out how to use nRF24L01 for BLE.
Read his amazing "Bit-banging" Bluetooth Low Energy. Thank you Dmitry!
I ported the code to mbed from Lijun's repository. Read his very neat article on the topic. Thank you Lijun!

It takes just few steps to build a Temperature Beacon

Connect the nRF24L01(+) module and the DS1820 sensor to the mbed board according to the pin assignment defined in main.cpp. Don't forget to connect a 4.7k Ohm resistor between the DS1820's data pin and the +3.3V pin.

Figure 2: nRF24L01(+) pinout
Compile the project and save the binary file to your mbed module.
Enable Bluetooth on the Android device.
To view the raw data, install Nordic's nRF Master Control Panel (available at Google Play for free) to your Android device. Run the app and wait until a new nRF24L01 device is found. Do not tap the CONNECT button. This device is a broadcaster and enables only one way data flow (from the mbed to the Android). To see more details, tap the found nRF24L01 device on the left side of the screen and then the small RAW button which appears on the right side just below the CONNECT button. Now you should be able to see and check the raw bytes received from the mbed.
Install the Android app:
- Download the TemperatureBeacon app to your computer's folder of choice.
- Open the folder and copy (send via Bluetooth or USB cable) the downloaded file to your Android device.
- To install the app, open the folder on the Android with the file downloaded in the previous step and tap it.
Once the app is installed and running:
- After a while you should see the temperature displayed on Android (See in Figure 1).
- Data is periodically updated. To verify that, touch the DS1820 sensor and you should see some new values.

If you'd like to adapt the Android app to your taste

Install Android Studio onto your computer (Window, Mac, Linux). It's a fantastic IDE from Google for free.
Download the Android app project to your computer's folder of choice and unzip.
Start Android Studio, open the project downloaded in the previous step and have fun.

I have learnt a lot about Android and Bluetooth Low Energy here:
https://developer.android.com/guide/topics/connectivity/bluetooth-le.html,
https://thenewcircle.com/s/post/1553/bluetooth_smart_le_android_tutorial

The Android app is based on:
https://github.com/devunwired/accessory-samples/tree/master/BluetoothGatt.
Thank you Dave!

main.cpp@0:6f3139e3410e, 2015-03-14 (annotated)

Committer:: hudakz
Date:: Sat Mar 14 07:34:03 2015 +0000
Revision:: 0:6f3139e3410e
Child:: 1:ef3cc9be1f60

nRF24L01+ as a Bluetooth Low Energy Broadcaster/Beacon

; by hacking an nRF24L01+ module (which is under $1 per unit on eBay).

Who changed what in which revision?

User	Revision	Line number	New contents of line
hudakz	0:6f3139e3410e	1	/*
hudakz	0:6f3139e3410e	2	nRF24L01+ as a Bluetooth Low Energy Broadcaster/Beacon
hudakz	0:6f3139e3410e	3	by hacking an nRF24L01+ module (which is under $1 per unit on eBay).
hudakz	0:6f3139e3410e	4
hudakz	0:6f3139e3410e	5	Note: It works also with the older nRF24L01 modules (without the +).
hudakz	0:6f3139e3410e	6
hudakz	0:6f3139e3410e	7	In this example we broadcast temperature readings measured by a DS1820 chip.
hudakz	0:6f3139e3410e	8	(You can easily modify the code to broadcast some other custom data.
hudakz	0:6f3139e3410e	9	Only make sure not to exceed the 32 bytes packet length.)
hudakz	0:6f3139e3410e	10
hudakz	0:6f3139e3410e	11	The data can be received and displayed on an Android device (smartphone/tablet)
hudakz	0:6f3139e3410e	12	with Bluetooth Low Energy (Bluetooth Smart) enabled.
hudakz	0:6f3139e3410e	13	In order to have Bluetooth 4.0 available (which implements Bluetooth LE)
hudakz	0:6f3139e3410e	14	your device should run Android 4.3 or later.
hudakz	0:6f3139e3410e	15
hudakz	0:6f3139e3410e	16	I ported this code to mbed from Lijun's repository <https://github.com/lijunxyz/nRF24_BLE>
hudakz	0:6f3139e3410e	17	Read his very neat article on the topic <http://wiki.lijun.xyz/misc-nrf24-ble.html>
hudakz	0:6f3139e3410e	18	and notice the nRF24L01(+) module pinout.
hudakz	0:6f3139e3410e	19	Thank you Lijun.
hudakz	0:6f3139e3410e	20
hudakz	0:6f3139e3410e	21	However, it all began with Dmitry Ginsberg's amazing "Bit-banging" Bluetooth Low Energy
hudakz	0:6f3139e3410e	22	<http://dmitry.gr/index.php?r=05.Projects&proj=11.%20Bluetooth%20LE%20fakery>
hudakz	0:6f3139e3410e	23	Thank you Dmitry.
hudakz	0:6f3139e3410e	24
hudakz	0:6f3139e3410e	25	After programming the mbed, enable Bluetooth on the Android device (smartphone/tablet).
hudakz	0:6f3139e3410e	26	To view the custom data, install "nRF Master Control Panel" from Nordic (available at Google Play Store).
hudakz	0:6f3139e3410e	27	Run the app and wait until a new device "nRF24L01" is found. Do not tap the "CONNECT" button.
hudakz	0:6f3139e3410e	28	This device is an advertiser and enables only one way data flow (from the mbed to the Android).
hudakz	0:6f3139e3410e	29	To see more details, tap the found device "nRF24L01" on the left side of the screen
hudakz	0:6f3139e3410e	30	and then the small "RAW" button which appears on the right side just below the "CONNECT" button.
hudakz	0:6f3139e3410e	31	Then you should be able to see and check the raw bytes received from the mbed.
hudakz	0:6f3139e3410e	32	That's nice. But if you would like to have more fun and see the temperature readings
hudakz	0:6f3139e3410e	33	then download "Temperature Beacon" from Google Play Store or to have even bigger fun you better build your own Android app.
hudakz	0:6f3139e3410e	34	It's easy (as everithing, once you know how :)
hudakz	0:6f3139e3410e	35	- Install "Android Studio" onto your PC/Mac (it's a fantastic IDE from Google for free)
hudakz	0:6f3139e3410e	36	- Download the app project from "..." to your PC/Mac folder of choice
hudakz	0:6f3139e3410e	37	- Start "Android Studio" and open the project downloaded in the previous step
hudakz	0:6f3139e3410e	38	- Connect your Android device to the PC/Mac via USB (make sure that the USB driver is installed on your PC/Mac
hudakz	0:6f3139e3410e	39	and "USB debugging" is enabled in "Developer Options" on your Android device)
hudakz	0:6f3139e3410e	40	- Run the project in "Android Studio". When you are asked, choose your Android device (phone/tablet) from the list as running device
hudakz	0:6f3139e3410e	41	- Once the app is installed and running, after a few seconds you should see on your Android the temperature readings
hudakz	0:6f3139e3410e	42	- The data is periodically updated to have the illusion of a connected device
hudakz	0:6f3139e3410e	43	- To verify that, touch the DS1820 sensor with your finger and you should see some new readings...
hudakz	0:6f3139e3410e	44
hudakz	0:6f3139e3410e	45	I have learnt a lot from:
hudakz	0:6f3139e3410e	46	<https://developer.android.com/guide/topics/connectivity/bluetooth-le.html>
hudakz	0:6f3139e3410e	47	<https://thenewcircle.com/s/post/1553/bluetooth_smart_le_android_tutorial>
hudakz	0:6f3139e3410e	48	and borrowed the code for Android from here:
hudakz	0:6f3139e3410e	49	<https://github.com/devunwired/accessory-samples/tree/master/BluetoothGatt>
hudakz	0:6f3139e3410e	50	Thank you Dave.
hudakz	0:6f3139e3410e	51
hudakz	0:6f3139e3410e	52	*/
hudakz	0:6f3139e3410e	53
hudakz	0:6f3139e3410e	54
hudakz	0:6f3139e3410e	55	#include "mbed.h"
hudakz	0:6f3139e3410e	56	#include "DS1820.h"
hudakz	0:6f3139e3410e	57
hudakz	0:6f3139e3410e	58	Serial serial(USBTX, USBRX);
hudakz	0:6f3139e3410e	59
hudakz	0:6f3139e3410e	60	// The MAC address of BLE advertizer -- just make one up
hudakz	0:6f3139e3410e	61	// If you decide to ceate more Beacons make sure that MAC address (MY_MAC) is unique (differs)
hudakz	0:6f3139e3410e	62
hudakz	0:6f3139e3410e	63	#define MY_MAC_0 0x11
hudakz	0:6f3139e3410e	64	#define MY_MAC_1 0x12
hudakz	0:6f3139e3410e	65	#define MY_MAC_2 0x33
hudakz	0:6f3139e3410e	66	#define MY_MAC_3 0x44
hudakz	0:6f3139e3410e	67	#define MY_MAC_4 0x55
hudakz	0:6f3139e3410e	68	#define MY_MAC_5 0x66
hudakz	0:6f3139e3410e	69
hudakz	0:6f3139e3410e	70	#if defined(TARGET_LPC1768)
hudakz	0:6f3139e3410e	71	SPI spi(p11, p12, p13); // MOSI, MISO, SCK
hudakz	0:6f3139e3410e	72	DigitalOut cs(p8); // CSN (select SPI chip/slave)
hudakz	0:6f3139e3410e	73	DigitalOut ce(p14); // CE (enable nRF24L01+ chip)
hudakz	0:6f3139e3410e	74	DS1820 ds1820(p15);
hudakz	0:6f3139e3410e	75	#elif defined(TARGET_NUCLEO_F103RB)
hudakz	0:6f3139e3410e	76	SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz	0:6f3139e3410e	77	DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz	0:6f3139e3410e	78	DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz	0:6f3139e3410e	79	DS1820 ds1820(PA_9);
hudakz	0:6f3139e3410e	80	#elif defined(TARGET_NUCLEO_F401RE)
hudakz	0:6f3139e3410e	81	SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz	0:6f3139e3410e	82	DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz	0:6f3139e3410e	83	DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz	0:6f3139e3410e	84	DS1820 ds1820(PA_9);
hudakz	0:6f3139e3410e	85	#elif defined(TARGET_NUCLEO_F411RE)
hudakz	0:6f3139e3410e	86	SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz	0:6f3139e3410e	87	DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz	0:6f3139e3410e	88	DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz	0:6f3139e3410e	89	DS1820 ds1820(PA_9);
hudakz	0:6f3139e3410e	90
hudakz	0:6f3139e3410e	91	// If your board/plaform is not present yet then uncomment
hudakz	0:6f3139e3410e	92	// the following four lines and replace TARGET_YOUR_BOARD and CE_PIN as appropriate.
hudakz	0:6f3139e3410e	93
hudakz	0:6f3139e3410e	94	//#elif defined(TARGET_YOUR_BOARD)
hudakz	0:6f3139e3410e	95	//SPI spi(SPI_MOSI, SPI_MISO, SPI_SCK);
hudakz	0:6f3139e3410e	96	//DigitalOut cs(SPI_CS); // CSN (select SPI chip/slave)
hudakz	0:6f3139e3410e	97	//DigitalOut cs(CE_PIN); // CE (enable nRF24L01+ chip)
hudakz	0:6f3139e3410e	98	//DS1820 ds1820(DS1820_PIN);
hudakz	0:6f3139e3410e	99
hudakz	0:6f3139e3410e	100	#endif
hudakz	0:6f3139e3410e	101
hudakz	0:6f3139e3410e	102	uint8_t buf[32];
hudakz	0:6f3139e3410e	103
hudakz	0:6f3139e3410e	104	/**
hudakz	0:6f3139e3410e	105	* @brief
hudakz	0:6f3139e3410e	106	* @note
hudakz	0:6f3139e3410e	107	* @param
hudakz	0:6f3139e3410e	108	* @retval
hudakz	0:6f3139e3410e	109	*/
hudakz	0:6f3139e3410e	110	void bleCRC(const uint8_t* data, uint8_t len, uint8_t* dst) {
hudakz	0:6f3139e3410e	111
hudakz	0:6f3139e3410e	112	// implementing CRC with LFSR
hudakz	0:6f3139e3410e	113	uint8_t v, t, d;
hudakz	0:6f3139e3410e	114
hudakz	0:6f3139e3410e	115	while(len--) {
hudakz	0:6f3139e3410e	116	d = *data++;
hudakz	0:6f3139e3410e	117	for(v = 0; v < 8; v++, d >>= 1) {
hudakz	0:6f3139e3410e	118	t = dst[0] >> 7;
hudakz	0:6f3139e3410e	119	dst[0] <<= 1;
hudakz	0:6f3139e3410e	120	if(dst[1] & 0x80)
hudakz	0:6f3139e3410e	121	dst[0] \|= 1;
hudakz	0:6f3139e3410e	122	dst[1] <<= 1;
hudakz	0:6f3139e3410e	123	if(dst[2] & 0x80)
hudakz	0:6f3139e3410e	124	dst[1] \|= 1;
hudakz	0:6f3139e3410e	125	dst[2] <<= 1;
hudakz	0:6f3139e3410e	126
hudakz	0:6f3139e3410e	127	if(t != (d & 1)) {
hudakz	0:6f3139e3410e	128	dst[2] ^= 0x5B;
hudakz	0:6f3139e3410e	129	dst[1] ^= 0x06;
hudakz	0:6f3139e3410e	130	}
hudakz	0:6f3139e3410e	131	}
hudakz	0:6f3139e3410e	132	}
hudakz	0:6f3139e3410e	133	}
hudakz	0:6f3139e3410e	134
hudakz	0:6f3139e3410e	135	/**
hudakz	0:6f3139e3410e	136	* @brief
hudakz	0:6f3139e3410e	137	* @note
hudakz	0:6f3139e3410e	138	* @param
hudakz	0:6f3139e3410e	139	* @retval
hudakz	0:6f3139e3410e	140	*/
hudakz	0:6f3139e3410e	141	uint8_t swapBits(uint8_t a) {
hudakz	0:6f3139e3410e	142
hudakz	0:6f3139e3410e	143	// reverse the bit order in a single byte
hudakz	0:6f3139e3410e	144	uint8_t v = 0;
hudakz	0:6f3139e3410e	145	if(a & 0x80)
hudakz	0:6f3139e3410e	146	v \|= 0x01;
hudakz	0:6f3139e3410e	147	if(a & 0x40)
hudakz	0:6f3139e3410e	148	v \|= 0x02;
hudakz	0:6f3139e3410e	149	if(a & 0x20)
hudakz	0:6f3139e3410e	150	v \|= 0x04;
hudakz	0:6f3139e3410e	151	if(a & 0x10)
hudakz	0:6f3139e3410e	152	v \|= 0x08;
hudakz	0:6f3139e3410e	153	if(a & 0x08)
hudakz	0:6f3139e3410e	154	v \|= 0x10;
hudakz	0:6f3139e3410e	155	if(a & 0x04)
hudakz	0:6f3139e3410e	156	v \|= 0x20;
hudakz	0:6f3139e3410e	157	if(a & 0x02)
hudakz	0:6f3139e3410e	158	v \|= 0x40;
hudakz	0:6f3139e3410e	159	if(a & 0x01)
hudakz	0:6f3139e3410e	160	v \|= 0x80;
hudakz	0:6f3139e3410e	161	return v;
hudakz	0:6f3139e3410e	162	}
hudakz	0:6f3139e3410e	163
hudakz	0:6f3139e3410e	164	/**
hudakz	0:6f3139e3410e	165	* @brief
hudakz	0:6f3139e3410e	166	* @note
hudakz	0:6f3139e3410e	167	* @param
hudakz	0:6f3139e3410e	168	* @retval
hudakz	0:6f3139e3410e	169	*/
hudakz	0:6f3139e3410e	170	void bleWhiten(uint8_t* data, uint8_t len, uint8_t whitenCoeff) {
hudakz	0:6f3139e3410e	171
hudakz	0:6f3139e3410e	172	// Implementing whitening with LFSR
hudakz	0:6f3139e3410e	173	uint8_t m;
hudakz	0:6f3139e3410e	174	while(len--) {
hudakz	0:6f3139e3410e	175	for(m = 1; m; m <<= 1) {
hudakz	0:6f3139e3410e	176	if(whitenCoeff & 0x80) {
hudakz	0:6f3139e3410e	177	whitenCoeff ^= 0x11;
hudakz	0:6f3139e3410e	178	(*data) ^= m;
hudakz	0:6f3139e3410e	179	}
hudakz	0:6f3139e3410e	180
hudakz	0:6f3139e3410e	181	whitenCoeff <<= 1;
hudakz	0:6f3139e3410e	182	}
hudakz	0:6f3139e3410e	183
hudakz	0:6f3139e3410e	184	data++;
hudakz	0:6f3139e3410e	185	}
hudakz	0:6f3139e3410e	186	}
hudakz	0:6f3139e3410e	187
hudakz	0:6f3139e3410e	188	/**
hudakz	0:6f3139e3410e	189	* @brief
hudakz	0:6f3139e3410e	190	* @note
hudakz	0:6f3139e3410e	191	* @param
hudakz	0:6f3139e3410e	192	* @retval
hudakz	0:6f3139e3410e	193	*/
hudakz	0:6f3139e3410e	194	static inline uint8_t bleWhitenStart(uint8_t chan) {
hudakz	0:6f3139e3410e	195
hudakz	0:6f3139e3410e	196	//the value we actually use is what BT'd use left shifted one...makes our life easier
hudakz	0:6f3139e3410e	197
hudakz	0:6f3139e3410e	198	return swapBits(chan) \| 2;
hudakz	0:6f3139e3410e	199	}
hudakz	0:6f3139e3410e	200
hudakz	0:6f3139e3410e	201	/**
hudakz	0:6f3139e3410e	202	* @brief
hudakz	0:6f3139e3410e	203	* @note
hudakz	0:6f3139e3410e	204	* @param
hudakz	0:6f3139e3410e	205	* @retval
hudakz	0:6f3139e3410e	206	*/
hudakz	0:6f3139e3410e	207	void blePacketEncode(uint8_t* packet, uint8_t len, uint8_t chan) {
hudakz	0:6f3139e3410e	208
hudakz	0:6f3139e3410e	209	// Assemble the packet to be transmitted
hudakz	0:6f3139e3410e	210
hudakz	0:6f3139e3410e	211	// Length is of packet, including crc. pre-populate crc in packet with initial crc value!
hudakz	0:6f3139e3410e	212	uint8_t i, dataLen = len - 3;
hudakz	0:6f3139e3410e	213	bleCRC(packet, dataLen, packet + dataLen);
hudakz	0:6f3139e3410e	214	for(i = 0; i < 3; i++, dataLen++)
hudakz	0:6f3139e3410e	215	packet[dataLen] = swapBits(packet[dataLen]);
hudakz	0:6f3139e3410e	216	bleWhiten(packet, len, bleWhitenStart(chan));
hudakz	0:6f3139e3410e	217	for(i = 0; i < len; i++)
hudakz	0:6f3139e3410e	218	packet[i] = swapBits(packet[i]); // the byte order of the packet should be reversed as well
hudakz	0:6f3139e3410e	219	}
hudakz	0:6f3139e3410e	220
hudakz	0:6f3139e3410e	221	/**
hudakz	0:6f3139e3410e	222	* @brief
hudakz	0:6f3139e3410e	223	* @note
hudakz	0:6f3139e3410e	224	* @param
hudakz	0:6f3139e3410e	225	* @retval
hudakz	0:6f3139e3410e	226	*/
hudakz	0:6f3139e3410e	227	void nrfCmd(uint8_t cmd, uint8_t data) {
hudakz	0:6f3139e3410e	228
hudakz	0:6f3139e3410e	229	// Write to nRF24's register
hudakz	0:6f3139e3410e	230
hudakz	0:6f3139e3410e	231	cs = 0;
hudakz	0:6f3139e3410e	232	spi.write(cmd);
hudakz	0:6f3139e3410e	233	spi.write(data);
hudakz	0:6f3139e3410e	234	cs = 1;
hudakz	0:6f3139e3410e	235	}
hudakz	0:6f3139e3410e	236
hudakz	0:6f3139e3410e	237	/**
hudakz	0:6f3139e3410e	238	* @brief
hudakz	0:6f3139e3410e	239	* @note
hudakz	0:6f3139e3410e	240	* @param
hudakz	0:6f3139e3410e	241	* @retval
hudakz	0:6f3139e3410e	242	*/
hudakz	0:6f3139e3410e	243	void nrfWriteByte(uint8_t cmd) {
hudakz	0:6f3139e3410e	244	// transfer only one byte
hudakz	0:6f3139e3410e	245	cs = 0;
hudakz	0:6f3139e3410e	246	spi.write(cmd);
hudakz	0:6f3139e3410e	247	cs = 1;
hudakz	0:6f3139e3410e	248	}
hudakz	0:6f3139e3410e	249
hudakz	0:6f3139e3410e	250	/**
hudakz	0:6f3139e3410e	251	* @brief
hudakz	0:6f3139e3410e	252	* @note
hudakz	0:6f3139e3410e	253	* @param
hudakz	0:6f3139e3410e	254	* @retval
hudakz	0:6f3139e3410e	255	*/
hudakz	0:6f3139e3410e	256	void nrfWriteBytes(uint8_t* data, uint8_t len) {
hudakz	0:6f3139e3410e	257	// transfer several bytes in a row
hudakz	0:6f3139e3410e	258	cs = 0;
hudakz	0:6f3139e3410e	259	do
hudakz	0:6f3139e3410e	260	{
hudakz	0:6f3139e3410e	261	spi.write(*data++);
hudakz	0:6f3139e3410e	262	} while(--len);
hudakz	0:6f3139e3410e	263	cs = 1;
hudakz	0:6f3139e3410e	264	}
hudakz	0:6f3139e3410e	265
hudakz	0:6f3139e3410e	266	int main() {
hudakz	0:6f3139e3410e	267	uint8_t data[4];
hudakz	0:6f3139e3410e	268	float* temp = reinterpret_cast < float * > (&data[0]);
hudakz	0:6f3139e3410e	269
hudakz	0:6f3139e3410e	270	// Chip must be deselected
hudakz	0:6f3139e3410e	271	cs = 1;
hudakz	0:6f3139e3410e	272
hudakz	0:6f3139e3410e	273	// Setup the spi for 8 bit data, high steady state clock,
hudakz	0:6f3139e3410e	274	// second edge capture, with a 10MHz clock rate
hudakz	0:6f3139e3410e	275	spi.format(8,0);
hudakz	0:6f3139e3410e	276	spi.frequency(10000000);
hudakz	0:6f3139e3410e	277
hudakz	0:6f3139e3410e	278	cs = 1;
hudakz	0:6f3139e3410e	279	ce = 0;
hudakz	0:6f3139e3410e	280
hudakz	0:6f3139e3410e	281	// Initialize nRF24L01+, setting general parameters
hudakz	0:6f3139e3410e	282	nrfCmd(0x20, 0x12); // on, no crc, int on RX/TX done
hudakz	0:6f3139e3410e	283	nrfCmd(0x21, 0x00); // no auto-acknowledge
hudakz	0:6f3139e3410e	284	nrfCmd(0x22, 0x00); // no RX
hudakz	0:6f3139e3410e	285	nrfCmd(0x23, 0x02); // 4-byte address
hudakz	0:6f3139e3410e	286	nrfCmd(0x24, 0x00); // no auto-retransmit
hudakz	0:6f3139e3410e	287	nrfCmd(0x26, 0x06); // 1MBps at 0dBm
hudakz	0:6f3139e3410e	288	nrfCmd(0x27, 0x3E); // clear various flags
hudakz	0:6f3139e3410e	289	nrfCmd(0x3C, 0x00); // no dynamic payloads
hudakz	0:6f3139e3410e	290	nrfCmd(0x3D, 0x00); // no features
hudakz	0:6f3139e3410e	291	nrfCmd(0x31, 32); // always RX 32 bytes
hudakz	0:6f3139e3410e	292	nrfCmd(0x22, 0x01); // RX on pipe 0
hudakz	0:6f3139e3410e	293
hudakz	0:6f3139e3410e	294	// Set access addresses (TX address in nRF24L01) to BLE advertising 0x8E89BED6
hudakz	0:6f3139e3410e	295	// Remember that both bit and byte orders are reversed for BLE packet format
hudakz	0:6f3139e3410e	296	buf[0] = 0x30;
hudakz	0:6f3139e3410e	297	buf[1] = swapBits(0x8E);
hudakz	0:6f3139e3410e	298	buf[2] = swapBits(0x89);
hudakz	0:6f3139e3410e	299	buf[3] = swapBits(0xBE);
hudakz	0:6f3139e3410e	300	buf[4] = swapBits(0xD6);
hudakz	0:6f3139e3410e	301	nrfWriteBytes(buf, 5);
hudakz	0:6f3139e3410e	302	buf[0] = 0x2A; // set RX address in nRF24L01, doesn't matter because RX is ignored in this case
hudakz	0:6f3139e3410e	303	nrfWriteBytes(buf, 5);
hudakz	0:6f3139e3410e	304	ds1820.begin();
hudakz	0:6f3139e3410e	305
hudakz	0:6f3139e3410e	306	while(1) {
hudakz	0:6f3139e3410e	307	static const uint8_t chRf[] = { 2, 26, 80 };
hudakz	0:6f3139e3410e	308	static const uint8_t chLe[] = { 37, 38, 39 };
hudakz	0:6f3139e3410e	309	uint8_t i = 0;
hudakz	0:6f3139e3410e	310	uint8_t j = 0;
hudakz	0:6f3139e3410e	311	uint8_t ch = 0;
hudakz	0:6f3139e3410e	312
hudakz	0:6f3139e3410e	313	*temp = ds1820.read();
hudakz	0:6f3139e3410e	314
hudakz	0:6f3139e3410e	315	// serial.printf("temp = %3.1f'C\r\n", *temp);
hudakz	0:6f3139e3410e	316
hudakz	0:6f3139e3410e	317	buf[i++] = 0x42; // PDU type, given address is random; 0x42 for Android and 0x40 for iPhone
hudakz	0:6f3139e3410e	318	buf[i++] = 25; // number of following data bytes, max 29 (CRC is not included)
hudakz	0:6f3139e3410e	319
hudakz	0:6f3139e3410e	320	//----------------------------
hudakz	0:6f3139e3410e	321	buf[i++] = MY_MAC_0;
hudakz	0:6f3139e3410e	322	buf[i++] = MY_MAC_1;
hudakz	0:6f3139e3410e	323	buf[i++] = MY_MAC_2;
hudakz	0:6f3139e3410e	324	buf[i++] = MY_MAC_3;
hudakz	0:6f3139e3410e	325	buf[i++] = MY_MAC_4;
hudakz	0:6f3139e3410e	326	buf[i++] = MY_MAC_5;
hudakz	0:6f3139e3410e	327
hudakz	0:6f3139e3410e	328	buf[i++] = 2; // flags (LE-only, limited discovery mode)
hudakz	0:6f3139e3410e	329	buf[i++] = 0x01;
hudakz	0:6f3139e3410e	330	buf[i++] = 0x05;
hudakz	0:6f3139e3410e	331
hudakz	0:6f3139e3410e	332	buf[i++] = 9; // length of the name, including type byte
hudakz	0:6f3139e3410e	333	buf[i++] = 0x08; // TYPE_NAME_SHORT
hudakz	0:6f3139e3410e	334	buf[i++] = 'n';
hudakz	0:6f3139e3410e	335	buf[i++] = 'R';
hudakz	0:6f3139e3410e	336	buf[i++] = 'F';
hudakz	0:6f3139e3410e	337	buf[i++] = '2';
hudakz	0:6f3139e3410e	338	buf[i++] = '4';
hudakz	0:6f3139e3410e	339	buf[i++] = 'L';
hudakz	0:6f3139e3410e	340	buf[i++] = '0';
hudakz	0:6f3139e3410e	341	buf[i++] = '1';
hudakz	0:6f3139e3410e	342
hudakz	0:6f3139e3410e	343	buf[i++] = 5; // length of custom data, including type byte
hudakz	0:6f3139e3410e	344	buf[i++] = 0xff; // TYPE_CUSTOMDATA
hudakz	0:6f3139e3410e	345
hudakz	0:6f3139e3410e	346	buf[i++] = data[0]; // temperature floating point value (four bytes)
hudakz	0:6f3139e3410e	347	buf[i++] = data[1];
hudakz	0:6f3139e3410e	348	buf[i++] = data[2];
hudakz	0:6f3139e3410e	349	buf[i++] = data[3];
hudakz	0:6f3139e3410e	350	//----------------------------
hudakz	0:6f3139e3410e	351
hudakz	0:6f3139e3410e	352	buf[i++] = 0x55; // CRC start value: 0x555555
hudakz	0:6f3139e3410e	353	buf[i++] = 0x55;
hudakz	0:6f3139e3410e	354	buf[i++] = 0x55;
hudakz	0:6f3139e3410e	355
hudakz	0:6f3139e3410e	356	// Channel hopping
hudakz	0:6f3139e3410e	357	if(++ch == sizeof(chRf))
hudakz	0:6f3139e3410e	358	ch = 0;
hudakz	0:6f3139e3410e	359	nrfCmd(0x25, chRf[ch]);
hudakz	0:6f3139e3410e	360	nrfCmd(0x27, 0x6E); // Clear flags
hudakz	0:6f3139e3410e	361	blePacketEncode(buf, i, chLe[ch]);
hudakz	0:6f3139e3410e	362	nrfWriteByte(0xE2); // Clear RX Fifo
hudakz	0:6f3139e3410e	363	nrfWriteByte(0xE1); // Clear TX Fifo
hudakz	0:6f3139e3410e	364	cs = 0;
hudakz	0:6f3139e3410e	365	spi.write(0xA0);
hudakz	0:6f3139e3410e	366	for(j = 0; j < i; j++)
hudakz	0:6f3139e3410e	367	spi.write(buf[j]);
hudakz	0:6f3139e3410e	368	cs = 1;
hudakz	0:6f3139e3410e	369
hudakz	0:6f3139e3410e	370	nrfCmd(0x20, 0x12); // TX on
hudakz	0:6f3139e3410e	371	ce = 1; // Enable Chip
hudakz	0:6f3139e3410e	372	wait_ms(50);
hudakz	0:6f3139e3410e	373	ce = 0; // (in preparation of switching to RX quickly)
hudakz	0:6f3139e3410e	374	ds1820.startConversion(); // Start temperature conversion
hudakz	0:6f3139e3410e	375	wait(1); // Broadcasting interval (change to your needs)
hudakz	0:6f3139e3410e	376	}
hudakz	0:6f3139e3410e	377	}

Repository toolbox

Export to desktop IDE

Build repository

Repository details

Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	14 Mar 2015
Imports:	229
Forks:	0
Commits:	8
Dependents:	0
Dependencies:	2
Followers:	7