Wireless Accelerometer

Wireless Accelerometer Documentation

Data Mode

In the RUN mode device will send raw acceleration data according to user defined settings. 

A Sample packet will look like this 

7E 00 C9 90 00 13 A2 00 41 8E A5 D6 FF FE C1 7F 01 00 03 FF DE 00 65 01 01 0A 07 13 0B 00 00 77 01 01 DE FF 7A 3F 8B 01 E1 FF 83 3F BB 01 E0 FF 92 3F D4 01 D4 FF 8F 3F B5 01 D0 FF A6 3F B5 01 D3 FF CB 3F B5 01 D5 FF DD 3F C4 01 D5 FF EB 3F C1 01 D8 FF D3 3F AE 01 DB FF BB 3F 9E 01 EE FF AA 3F A5 02 0C FF A0 3F CA 02 11 FF 9E 40 0D 01 FD FF 88 40 45 01 E6 FF 91 40 4C 01 DA FF 8B 40 8E 01 D2 FF 7E 40 CC 01 DC FF AD 40 DD 01 F2 FF C6 40 F6 01 E6 FF B5 40 E8 01 D4 FF A4 40 CA 01 D4 FF 7D 40 A0 01 E3 FF 55 40 67 01 F2 FF 62 40 4A 01 EB FF 70 40 2B 01 EB FF 6D 40 0A 01 ED FF 75 3F F9 01 E8 FF 65 3F E2 01 E9 FF 81

This packet can be broken down in two Section

  1. Complete API
  2. Device Specific data

Complete API mainly contains Device MAC address, and Device Specific Data.

In The above complete API packet the Device specific data is 

7F 01 00 03 FF DE 00 65 01 01 0A 07 13 0B 00 00 77 01 01 DE FF 7A 3F 8B 01 E1 FF 83 3F BB 01 E0 FF 92 3F D4 01 D4 FF 8F 3F B5 01 D0 FF A6 3F B5 01 D3 FF CB 3F B5 01 D5 FF DD 3F C4 01 D5 FF EB 3F C1 01 D8 FF D3 3F AE 01 DB FF BB 3F 9E 01 EE FF AA 3F A5 02 0C FF A0 3F CA 02 11 FF 9E 40 0D 01 FD FF 88 40 45 01 E6 FF 91 40 4C 01 DA FF 8B 40 8E 01 D2 FF 7E 40 CC 01 DC FF AD 40 DD 01 F2 FF C6 40 F6 01 E6 FF B5 40 E8 01 D4 FF A4 40 CA 01 D4 FF 7D 40 A0 01 E3 FF 55 40 67 01 F2 FF 62 40 4A 01 EB FF 70 40 2B 01 EB FF 6D 40 0A 01 ED FF 75 3F F9 01 E8 FF 65 3F E2 01 E9 FF

Device Specific Data can be broken down into two Section

  1. Device Meta Data
  2. Sensor Payload

Device Meta Data

Value Info
7FMetadata Header
01Node ID ( Every Device Must have Unique Node ID)
00Firmware Version
03,FFBattery Voltage , battery % = raw_adc * 0.537 – 449.3
DEWireless Packet Counter
00,65Device Type
01Reserve Byte
PLP Sensor RUN mode device metadata

Accelerometer Sensor Payload

Field Description
01Mode Of Operation
0AODR
07Enabled Axis
13Hour
0BMinute
00,00Device Temperature
00,00External Temperature
77Total Number of RF Packets
01Current Packet Count value
01 DEX-Axis RAW ACC Data
FF 7AY-Axis RAW ACC Data
3F 8BY-Axis RAW ACC Data

Number of Total Packet and length of packet can change based on user configuration. 

Strain Gauge Sensor Payload 

Sensor Type — 0x66

Field Description
0AODR
13Hour
0BMinute
00,00Device Temperature
00,00External Temperature
77Total Number of RF Packets
01Current Packet Count value
01 DERAW ADC Data

Number of Total Packet and length of packet can change based on user configuration. 

 

Configuration Mode

In this mode user can change device parameters. This device supports all the existing ncd sensor configuration  parameters like Network ID, Node ID, Destination Address, ENY Key, Retries, RF Power etc. Detailed info can be found here

NCD Wireless Sensor Configuration Commands

COMMANDCOMMANDSUB COMMANDCOMMAND CODEARGUMENT
SET OUTPUT DATA RATEF44F0x00ODR 50 Hz 0x06
ODR 100 Hz 0x07
ODR 200 Hz 0x08
ODR 400 Hz 0x09
ODR 800 Hz 0x0A
ODR 1600 Hz 0x0B

GET OUTPUT DATA RATE F44F0x01ODR 50 Hz 0x06
ODR 100 Hz 0x07
ODR 200 Hz 0x08
ODR 400 Hz 0x09
ODR 800 Hz 0x0A
ODR 1600 Hz 0x0B

SET SAMPLING DURATIONF44F0x02Period of samples in seconds
must be > 0
GET SAMPLING DURATIONF44F0x03
SET AXES ENABLEF44F0x04Bit 0 —> X-axis
Bit 1 —> Y-axis
Bit 2 —> Z-axis

Bit Set – Axis enabled
Bit Cleared – Axis disabled
GET AXES ENABLEF44F0x05
SET SAMPLING INTERVALF44F0x06Every 5 minutes 0x0
Every 10 minutes 0x01
Every 15 minutes 0x02
Every 20 minutes 0x03
Every 30 minutes 0x04
GET SAMPLING INTERVALF44F0x07
SET RTCF44F0x08Byte 1 : Hours
Byte 2 : Minutes
Byte 3 : Seconds
SET FULL-SCALE RANGEF44F0x0B+/- 2g 0x00
+/- 4g 0x01
+/- 8g 0x02
+/- 16g 0x03
GET FULL-SCALE RANGEF44F0x0C+/- 2g 0x00
+/- 4g 0x01
+/- 8g 0x02
+/- 16g 0x03

NOTE– MAX number of samples are limited to 20KB. 

Sample Duration is inversely proportional to the ODR. 

How To Determine the Sample Duration —

The Total number of samples is 3400 when all 3 Axis are enabled. If only one axis is enabled then total number of samples will be 10,200.

For the calculation we will set the ODR to 800Hz. which means device will take 800 samples per second.

we are also assuming that all 3 Axis are enabled.

In this case the total time will be 3400/800 = 4. 25sec. 

The interval is always set in integer seconds, so in this case the max data sample time will be 4 sec. 

If  The ODR is  increased to 1600Hz, the total sample duration will reduce to 2sec.

If The ODR is decreased to 400Hz , The total sample duration will increase to 8sec. 

 

Example 1: Set ODR to 100 Hz (Node ID is 0)
Command packet should be F4 4F 00 00 65 00 07
00 Command Type (Set ODR)
07 Parameter Setting (100 Hz)

Example 2: Set sampling duration to 5 seconds (Node ID is 0)
Command packet should be F4 4F 00 00 65 02 05
02 Command Type (Set Sampling Duration)
05 Parameter Setting (5 seconds)

Example 3: Get ODR (Node ID is 0)
Command packet should be F4 4F 00 00 65 01
01 Command Type (Get ODR)

Example 4: Set sampling interval to “Every 5 minutes” (Node ID is 0)
Command packet should be F4 4F 00 00 65 06 00
06 Command Type (Set Sampling Interval)
00 Parameter Setting (Every 5 minutes)

Example 5: Set enabled axes (X & Z enabled , Y disabled)(Node ID is 0)
Command packet should be F4 4F 00 00 65 04 05
04 Command Type (Set Enabled Axes)
05 Parameter Setting (0000 0101 –→ X enabled , Y disabled , Z enabled)

Example 6: Set Real-time clock to 10:22:32 (Node ID is 0)
Command packet should be F4 4F 00 00 65 08 0A 16 20
08 Command Type (Set RTC)
0A 16 20 Parameter Setting (Hours = 10 , Minutes = 22 , Seconds = 32)

 

 

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