"Midge", an SPCL badge

Hardware

Hardware design files are in a separate hardware repo.

Advertisment Packet structure

The advertisment packet has a field called "manufacturer specific data", with type 0xFF. It should start at the 12th byte. Its length is 11 bytes:

typedef struct { uint8_t battery; uint8_t status_flags; uint16_t ID; uint8_t group; uint8_t MAC[6]; } custom_advdata_t;

MAC is set during init, ID and group with the status command. Battery is in percentage, and the status flags are : bit 0: clock sync bit 1: microphone bit 2: scanner bit 3: imu

0 is not active, 1 active.

Data format

Audio

On "high" audio is stereo, 20kHz, 16bit per channel PCM. On "low" it is subsampled by a factor of 32, to 625Hz.

It is only timestamped when the file is created (filename is seconds).

IMU

Filename is again timestamped, but also each sample (32 bytes):

accelerometer, gyro, magnetometer sample example: 2dd4 a69d 016d 0000 0000 3b40 0000 bc48 2000 3f83 0000 000c 0000 ffce 0000 1064

First 8 bytes are the timestamp: 2dd4 a69d 016d 0000 = 0000016da69d2dd4 = 1570458381780 milliseconds = 07/10/2019 2:26:780

4 bytes float per axis: 0000 3b40 0000 bc48 2000 3f83

padding for data alignment 0000 000c 0000 ffce 0000 1064

Rotation vector: Timestamp is the same 8 bytes, then 4 floats per quaternion, 4 fewer bytes for padding.

Scanner

16 byte length Same 8 byte timestamp. 2 bytes ID 1 int8_t rssi (signed) 1 byte group 4 bytes padding

the rest should be as you've asked on the requirements, please let me know if something is not clear

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BadgeFramework Hub

Runs on Ubuntu (21.10) on RPI platform. Raspberry pi 3B+ and 4 work.

Installation instructions

sudo apt install python3 python3-pip libglib2.0-dev pip3 install bluepy pandas

Start instructions

1. clone this repository

2. change to the BadgeFramework directory inside the cloned repo folder:

   cd BadgeFramework

3. Modify the sample_mapping_file.csv to include your sensors. See the maping dropdown.

   Mapings between device number and mac address

   Participant Id,Mac Address
   1,d5:46:26:05:1f:2f
   2,c3:4c:d5:ba:b1:44
   3,e5:93:96:ca:ee:c4
   4,f9:39:24:a9:04:f1
   5,d2:fd:13:bd:81:39
   6,de:94:80:39:25:be
   7,fb:f5:d5:84:a1:68
   8,e2:6e:4e:21:f1:a4
   9,f5:40:84:e2:9a:16
   10,e8:44:59:c0:39:de
   11,d7:11:de:c6:c8:e3
   12,fa:24:bd:55:c7:ab
   13,d6:12:78:32:80:19
   14,e8:03:31:16:ce:3a
   15,d8:ae:5b:aa:55:ae
   16,f5:ef:4c:9b:55:de
   17,c3:2b:78:b5:c2:4a
   18,c4:3e:0b:bc:e6:92
   19,d9:0d:2e:b7:cc:6b
   20,e6:cc:57:a3:6b:57
   21,c6:30:71:35:02:5a
   22,fb:42:af:eb:ba:3c
   23,d2:91:1c:b9:6f:5c
   24,c1:a4:56:be:7f:7e
   25,f2:26:6c:f5:ca:e5
   26,cb:14:eb:9a:5c:a3
   27,db:03:30:a6:ee:86
   28,fc:3f:62:28:17:b4
   29,ce:22:14:de:40:38
   30,e3:5d:06:9a:55:0f
   31,d4:56:f4:e1:ef:f1
   32,d2:4f:7c:01:93:0e
   33,da:03:10:bb:61:f5
   34,f5:e7:4d:77:4e:74
   35,fd:f3:eb:4b:d0:8c
   36,dc:bc:ed:19:1f:09
   37,c5:61:a9:e9:83:ef
   39,e7:03:db:e9:16:3b
   40,fe:82:88:fa:36:62
   41,dc:a4:f4:7e:45:fb
   42,f6:01:ad:d1:18:23
   43,e0:c3:d6:2e:ab:44
   44,de:7f:7f:a2:9c:f5
   45,fe:71:db:20:4f:34
   46,dc:11:e6:20:81:d8
   47,d9:98:8a:68:f0:89
   48,f7:5a:78:fd:21:46
   49,e9:59:12:26:a7:63
   50,d0:c5:cc:ef:90:e2
   

4. Start the hub

python3 hub_V1.py

5. enter the start command

usage instructions

1. Turn on Midges,make sure all of them blinked orange couple times. This means that they’re turned on and now on stand-by
2. run hub_V1.py
3. type “start” to start data collection on all midges
4. all midges should have a solid orange light when they’re recording

During data collection:

1. say verbally “experiment # start”
2. play the audiovisual events
3. say verbally “experiment # end”
4. In case of multiple takes, might need to stop recording on midges and start again.