OKKK now I am Clinically Deadddddd

But I am not gonna leave Sudden Impact WDC so easily


Sudden Impact Wearables Design Challenge has come to it's end. And I am far faar faaaar away from implementing my design fully. I feel awful for that.

However, I think it's my responsibility to share my work [whatever I have done so far] with others and for this reason I have posted this summarizing blog.


I have mentioned before in my previous updates that even after the deadline, I'll carry this project on. I'll post all of my details [including final codes] in regular blogs in my profile. It will be titled as "Total Player Monitor" tagged under "sudden_impact" and "total_player". I'll open / publish it after the official announcement of ending of this design challenge. So, officially this one is my last post in SIWDC.


Thank you all, to be a part of this great journey. I have enjoyed it so much. The way everyone co-operated with each other was a nice experience to me. I have learned a lot from this design challenge.




ModuleDescriptionCurrent statusFuture workBlog posts


Heart rate

AD8232 module is used for detecting Heart Bit Rate using LEAD02 ECG. A slightly modified well-known algorithm [PAN & TOMPKINS (1985)] is implemented in dsPIC microcontroller for detecting the heart rate precisely in spite of large motion artifact due to the body movements of the player.


Placement: Module is placed inside a pouch around the waist line of the short. Conductive fabric is used as electrode stitched to the sports tights.

Circuit was tested and PCB has been designed. The board is being assembled on time of writing this blog. RN4020 BLE module sends only the heart bit rate.

Slight modification is needed in the code to send real time ECG plot along with heart bit rate through RN4020 BLE module.
  • Introductory ECG LEAD arrangement

Part1.1 ECG LEAD arrangement

  • O/P of self designed AFE

Part1.2 ECG LEAD II output comparison

  • O/P of AD8232 AFE module

Part1.3 ECG output of AD8232

  • Beat detection algorithm

Part1.4 ECG Beat Rate [QRS complex detection]

  • Circuit design and PCB

Part 1.5 ECG module CKT and PCB


Muscle cramp

AD8232 module is used to measure the EMG from calf muscle. The filters has been changed carefully to maintain the Q parameter. Potential muscle cramp can be detected by observing the pattern of the EMG signal [BSAP with frequent Action Potential generation]. Wavelet analysis is required for developing the algorithm. A dsPIC33EP controller is used for processing and conditioning of the EMG.


Placement: Electrodes are placed at the back side of knee pad or belt of shin guard. The module is placed at the backside of the shin guard or outer side of knee pad.

So far the hardware has been designed and firmware is implemented with general muscle activity detection. RN4020 BLE module is used to send processed data which indicates different level of muscle activity.

Implementation of wavelet analysis for developing the algorithm to detect potential threat of muscle cramp.

Only firmware modification is needed, hardware will remain as it is.

  • Introductory muscle activity and cramp detection

Part2.1 - Muscle activity [Calf Muscle]


  • O/P from AD8232 for general calf muscle activity along with circuit and PCB design

Part2.2 - Calf Muscle Activity - CKT and Output


Head impact

ADXL377 is used to detect sudden strong impact causing potential concussion. Range: +/-200g.


Placement: The module will be placed inside of the head band or at the back of the sports helmet.

Experimented with a prototype hardware.

Design and manufacture of the PCB. Mounting in a head band or sports helmet to check real life performance.

  • ADXL 377 output

Part3.1 - Head Impact Detection [ADXL377]



[Central Hub]

ADT7320 temperature sensor is used to measure the body temperature. It's a part of the central hub. A dsPIC33EP microcontroller is used for data acquisition and BLE communication. It's the same microcontroller, which will handle other sub-modules of the central hub.


Placement: At the back of the wrist inside a wrist band.

ADT7320 is operated in single mode taking 1 sample per second for energy efficiency.

16-bit resolution has been selected for better accuracy.

Redesign with ADuCM350 meter-on-chip replacing the dsPIC. Later on ADuCM350 will be the heart of the central hub.
  • ADT7320 output

Part4.1 - ADT7320 Temperature Sensor [Central Hub]



[Central Hub]

By measuring the skin impedance, we can get a crude relative difference of body hydration parameter during a certain period of the game.

ADuCM350 meter-on-chip can be useful to

  • generate required sine wave
  • measure input current to the body skin
  • measure voltage output from skin
  • calculate impedance and relate dehydration


Placement: At the back of the wrist inside a wrist band.

A two electrode system has been used to experiment the variation of skin impedance with hydration.

The basic design consists of wave generator, current source, potential measurement and the same dsPIC microcontroller [of central hub] for processing. Only rough impedance measurement was taken, not ready yet for implementation.

Research on BIA study to relate hydration.

Implementation of Tetra polar system instead of two electrode system.

Replacement of dsPIC with ADuCM350 for small form factor, simplicity and better accuracy.

  • Crude measurement of Skin Impedance variation with body hydration

Part4.2 - Bio-impedance analysis over hydration [Central Hub]


Photo Plethysmograph

[Central Hub]

Detecting heart rate and blood oxygen saturation [SPO2] using photo-plethysmograph by IR and RED LED and Photodiode. The same ADuCM350 of the central hub will be a good choice for-

  • DAC -> helps to calibrate intensity of LEDs
  • AFE -> precise data acquisition
  • DFT -> for ratiometric measurements

4.4 / 1.1


Respiration rate can be derived by ECG and SPO2 plots. From ECG plots, respiration rate can be detected using famous R-R technique.ECG hardware is already implemented, so no need for extra setup.

ECG firmware up-gradation to calculate the R-R peak variation for a certain time period.



Communication bridge

Internal modules will be connected to the central hub through BLE. But a long range communication bridge is needed for sending data to the remote device. WT41 modules from BlueGiga can be used as it has a range over 500m at open space.


Element 14 has already provided a pair of WT41.



Remote monitoring device

A standalone remote device with display or Smart phone will be used to observe data.NOT IMPLEMENTED YETN/AN/A



An interesting last update:


Yesterday, I have received my PCB and components for the ECG and EMG modules those I have ordered separately. KHIKZZZZ

So, when I am preparing to pack up everything regarding Sudden Impact for a while, it gave me a new KICK and I have started working again .

Right now I am assembling the boards - hopefully I'll post the outcomes later on [blog - "Total Player Monitor" in my profile].

Best of luck to everyone




  ECG / EMG full module bare PCB beside AD8232 Evaluation board                      assembled PCB will be coated by resin and placed inside the transparent enclosure



some images on preparing the knee pad to place the EMG electrodes and module ->


Foam pad is placed to maintain an even pressure distribution on the electrodes         Copper tape is used to connect the cable with conductive fabric electrodes



Conductive fabric is stitched to use as EMG electrodes                                             Wires are soldered out from the outer side. Joints will be covered by resin and soft piece of cloth



So, officially...... Goodbye Sudden Impact Wearables Design Challenge. Thank you everyone .