ECG data acquisition with Analog device frontend and Redbear nano BLE
Dependencies: BLE_API mbed nRF51822
Fork of BLENano_SimpleControls by
Reference Design
2 channel EKG with Redbear BLE reference and Analog Device amplifier to generate RAW EKG data fed into Medtrics MaaS service . Medtrics API can consumer raw input with given parameters of ADC sample frequency and scaling factor
Specification
- Application Processor: nRF51822/BLE , Analog frontend: AD8232 /
- Input Analog Voltage = 3.3V
- 10 bit ADC input range = (0-1023) or scaling factor= 3.22mV/unit (this is ADC resolution)
- ADC sample frequency (BLE pull rate) = 250Hz (4ms per sample)
Reference IOS and Android app will be online soon!
main.cpp
- Committer:
- RedBearLab
- Date:
- 2015-07-27
- Revision:
- 2:3cd654f42efa
- Parent:
- 1:81a97eb70d3d
- Child:
- 3:f530ca03e014
File content as of revision 2:3cd654f42efa:
/* Copyright (c) 2012-2014 RedBearLab Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #include "mbed.h" #include "ble/BLE.h" #include "Servo.h" #define BLE_UUID_TXRX_SERVICE 0x0000 /**< The UUID of the Nordic UART Service. */ #define BLE_UUID_TX_CHARACTERISTIC 0x0002 /**< The UUID of the TX Characteristic. */ #define BLE_UUIDS_RX_CHARACTERISTIC 0x0003 /**< The UUID of the RX Characteristic. */ #define TXRX_BUF_LEN 20 #define DIGITAL_OUT_PIN P0_9 //TXD #define DIGITAL_IN_PIN P0_10 //CTS #define PWM_PIN P0_11 //RXD #define SERVO_PIN P0_8 //RTS #define ANALOG_IN_PIN P0_4 //P04 BLE ble; DigitalOut LED_SET(DIGITAL_OUT_PIN); DigitalIn BUTTON(DIGITAL_IN_PIN); PwmOut PWM(PWM_PIN); AnalogIn ANALOG(ANALOG_IN_PIN); Servo MYSERVO(SERVO_PIN); //Serial pc(USBTX, USBRX); static uint8_t analog_enabled = 0; static uint8_t old_state = 0; // The Nordic UART Service static const uint8_t uart_base_uuid[] = {0x71, 0x3D, 0, 0, 0x50, 0x3E, 0x4C, 0x75, 0xBA, 0x94, 0x31, 0x48, 0xF1, 0x8D, 0x94, 0x1E}; static const uint8_t uart_tx_uuid[] = {0x71, 0x3D, 0, 3, 0x50, 0x3E, 0x4C, 0x75, 0xBA, 0x94, 0x31, 0x48, 0xF1, 0x8D, 0x94, 0x1E}; static const uint8_t uart_rx_uuid[] = {0x71, 0x3D, 0, 2, 0x50, 0x3E, 0x4C, 0x75, 0xBA, 0x94, 0x31, 0x48, 0xF1, 0x8D, 0x94, 0x1E}; static const uint8_t uart_base_uuid_rev[] = {0x1E, 0x94, 0x8D, 0xF1, 0x48, 0x31, 0x94, 0xBA, 0x75, 0x4C, 0x3E, 0x50, 0, 0, 0x3D, 0x71}; uint8_t txPayload[TXRX_BUF_LEN] = {0,}; uint8_t rxPayload[TXRX_BUF_LEN] = {0,}; //static uint8_t rx_buf[TXRX_BUF_LEN]; //static uint8_t rx_len=0; GattCharacteristic txCharacteristic (uart_tx_uuid, txPayload, 1, TXRX_BUF_LEN, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE_WITHOUT_RESPONSE); GattCharacteristic rxCharacteristic (uart_rx_uuid, rxPayload, 1, TXRX_BUF_LEN, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY); GattCharacteristic *uartChars[] = {&txCharacteristic, &rxCharacteristic}; GattService uartService(uart_base_uuid, uartChars, sizeof(uartChars) / sizeof(GattCharacteristic *)); void disconnectionCallback(Gap::Handle_t handle, Gap::DisconnectionReason_t reason) { //pc.printf("Disconnected \r\n"); //pc.printf("Restart advertising \r\n"); ble.startAdvertising(); } void WrittenHandler(const GattWriteCallbackParams *Handler) { uint8_t buf[TXRX_BUF_LEN]; uint16_t bytesRead; if (Handler->handle == txCharacteristic.getValueAttribute().getHandle()) { ble.readCharacteristicValue(txCharacteristic.getValueAttribute().getHandle(), buf, &bytesRead); memset(txPayload, 0, TXRX_BUF_LEN); memcpy(txPayload, buf, TXRX_BUF_LEN); //for(index=0; index<bytesRead; index++) //pc.putc(buf[index]); if(buf[0] == 0x01) { if(buf[1] == 0x01) LED_SET = 1; else LED_SET = 0; } else if(buf[0] == 0xA0) { if(buf[1] == 0x01) analog_enabled = 1; else analog_enabled = 0; } else if(buf[0] == 0x02) { float value = (float)buf[1]/255; PWM = value; } else if(buf[0] == 0x03) { MYSERVO.write(buf[1]); } else if(buf[0] == 0x04) { analog_enabled = 0; PWM = 0; MYSERVO.write(0); LED_SET = 0; old_state = 0; } } } /* void uartCB(void) { while(pc.readable()) { rx_buf[rx_len++] = pc.getc(); if(rx_len>=20 || rx_buf[rx_len-1]=='\0' || rx_buf[rx_len-1]=='\n') { ble.updateCharacteristicValue(rxCharacteristic.getValueAttribute().getHandle(), rx_buf, rx_len); pc.printf("RecHandler \r\n"); pc.printf("Length: "); pc.putc(rx_len); pc.printf("\r\n"); rx_len = 0; break; } } } */ void m_status_check_handle(void) { uint8_t buf[3]; if (analog_enabled) // if analog reading enabled { // Read and send out float s = ANALOG; uint16_t value = s*1024; buf[0] = (0x0B); buf[1] = (value >> 8); buf[2] = (value); ble.updateCharacteristicValue(rxCharacteristic.getValueAttribute().getHandle(), buf, 3); } // If digital in changes, report the state if (BUTTON != old_state) { old_state = BUTTON; if (BUTTON == 1) { buf[0] = (0x0A); buf[1] = (0x01); buf[2] = (0x00); ble.updateCharacteristicValue(rxCharacteristic.getValueAttribute().getHandle(), buf, 3); } else { buf[0] = (0x0A); buf[1] = (0x00); buf[2] = (0x00); ble.updateCharacteristicValue(rxCharacteristic.getValueAttribute().getHandle(), buf, 3); } } } int main(void) { Ticker ticker; ticker.attach_us(m_status_check_handle, 200000); ble.init(); ble.onDisconnection(disconnectionCallback); ble.onDataWritten(WrittenHandler); //pc.baud(9600); //pc.printf("SimpleChat Init \r\n"); //pc.attach( uartCB , pc.RxIrq); // setup advertising ble.accumulateAdvertisingPayload(GapAdvertisingData::BREDR_NOT_SUPPORTED); ble.setAdvertisingType(GapAdvertisingParams::ADV_CONNECTABLE_UNDIRECTED); ble.accumulateAdvertisingPayload(GapAdvertisingData::SHORTENED_LOCAL_NAME, (const uint8_t *)"Biscuit", sizeof("Biscuit") - 1); ble.accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LIST_128BIT_SERVICE_IDS, (const uint8_t *)uart_base_uuid_rev, sizeof(uart_base_uuid)); // 100ms; in multiples of 0.625ms. ble.setAdvertisingInterval(160); ble.addService(uartService); ble.startAdvertising(); //pc.printf("Advertising Start \r\n"); while(1) { ble.waitForEvent(); } }