Quick Start Guide: ACB 2.0

The ACB connects to QTFM Gen-2 with a custom flexible printed circuit (FPC) cable. The standard cable length is either two feet or six inches. To install the ACB, remove the cable from the standard comms board and connect the cable to the ACB as shown in the video GIF image below.

Power: The ACB must be powered with a power source that has an output voltage ranging from +3.5V to +5.5V (max) and a minimum current of 2 amps. Powering the ACB will power the entire system (ACB, QTFM ECU, QTFM sensor head, GPS, and Bluetooth module). There are two power input options for the ACB. (1) the red and white terminal blocks, or (2) the micro-USB connector. Note: The micro-USB connector is for power alone and does not support a USB data connection. When connecting the power supply using the red and white terminal blocks, please make sure the polarity of the power supply is correct. The positive voltage from the power supply should connect to the red terminal, and the ground/negative voltage should connect to the white terminal.

The two power inputs are ‘hot-swap’ compatible, and both can be powered on at the same time. This feature is particularly useful when using an external battery pack to power the ACB via the red-white terminal blocks. In this case, if you need to replace the battery pack quickly, the micro-USB cable can provide temporary holdover power while the battery is being swapped out.

15-pin flex connector: This connector is used to connect the ACB to the QTFM electronics controller (ECU)

Sync-out (UMCC connector, output): 1 kHz, 3.3V square wave. The falling edge denotes the magnetic field measurement start time. Connecting sync-out from the master sensor to the sync-in of the slave sensor ensures the master and slave sensors are synchronized and make magnetic field measurements at the same instant. (link to the procedure to sync sensors)

Sync-in (UMCC connector, input): Accepts 1 kHz, 3.3V square wave to synchronize two or more QTFM Gen-2 sensors

Mag Data Pulse (MDP): +3.3V output pulse. MDP will stay low until the sensor has completed its AutoStart. The rising edge of MDP can be used as a jitter-free timestamp for the magnetometer data (1 pulse for each data sample that is transmitted)

Bluetooth w/Android

After powering on the ACB, you can communicate using a PC or smartphone over Bluetooth connection. The red light on the Bluetooth module will blink rapidly while waiting to be paired. To connect, go to settings on your device, select Bluetooth, then add a new device. The ACB should be discoverable as “QBT#” and the pairing password is “1234”. You should only need to pair with the ACB once. If you encounter any issues, try forgetting the device and pair again.

The Bluetooth module is programmed to default 115200 baud rate. Bluetooth can either transmit formatted data from the ACB (logger mode) or the raw data from QTFM (ECU mode), but not both simultaneously. A simple ASCII command (see below) can be sent to switch between the two modes.

When connecting to a PC, Bluetooth connection will show up as a serial com port. Once a connection to the com port is established, the red LED on the Bluetooth module will turn solid red. You can use the QTFM user interface to open the COM port and control the sensor, similar to when using the standard comms board (Bluetooth transmission should be set to ECU mode). Alternatively, you can use other terminal interfaces, such as Tera Term or PuTTY to communicate with the device in logger mode or in ECU mode. For iPhones, we recommend the Lightblue app, while for Android smartphones, the Serial Bluetooth Terminal (or terminal blue app) works well.

Viewing data from the ACB in logger mode is helpful to verify that no pre-arm errors have been detected and that the logger is ready to save data.

Note: When an ASCII command is sent to Bluetooth, it is read by both the sensor and the ACB independent of its transmission mode (logger/ECU). Below is a list of the ASCII commands for the ACB.


Decimal	ASCII	Command
102	f	Start saving data to SD card
103	g	Stop saving data to SD card
104	h	Switch BT to transmit in 'ECU' mode
65	A	Switch BT to transmit in 'logger' mode

Once logging has been initiated, it is recommended that you do not send commands to the sensor via Bluetooth except for the four commands above. You may configure the sensor using Bluetooth, but it should be done before data saving is active.

Once the ACB starts, it will load settings from a file named !quspin!.ini, located on the SD card. To configure the logger, edit this file on the SD card and save the changes. You can use Notepad on Windows for editing. Ensure the file is saved with the name !quspin!.ini. The default (suggested) configuration for !quspin!.ini is provided below.

;Start
; configure QuSpin logger operation
[config] ;
USE_GPS = true
; PA1616D and PA6H set GPS_TYPE=1
; NEO-M8N set GPS_TYPE=2
; NEO-M9N set GPS_TYPE=3
; PA1616S set GPS_TYPE=4
GPS_TYPE=1
PPS_TIMESTAMP = true
MAGDATA_PULSE_TIMESTAMP = true
MAX_FILE_SIZE_BYTES = 671088630
LOG_AT_STARTUP = false
MAG_DATA_REPEATER = false
RADIO_RATE = 57600
DEMO_MODE = false

LOG_FILE_BINARY = false
GPS_RATE = 115200
FILE_NAME_PREFIX = TFM
SLAVE_PRESENT = false
;End

When the ACB is powered up the teensy will begin its pre-arm checks. The logger will not initiate logging until it has successfully passed all of its pre-arm checks. If any part of the pre-arm check fails, the logger will restart the pre-arm check process until the pre-arm check is successful. The pre-arm checks are outlined below.

Check 1: The SD card is in the teensy SD card slot, and a !quspin!.ini file is on it.

Check 2: The logger will confirm that it is receiving data from the QTFM ECU. Note: This check only determines if sensor data is being received. It does not determine if the sensor is locked or if the sensitivity indicator is strong. To ensure the sensor is locked and outputting good data, check if the LED on the ECU is solid blue. You can also stream raw sensor data over Bluetooth to confirm by changing the ACB transmit mode to ‘ECU’.

Check 3: This check only occurs if the USE_GPS = true in the !quspin!.ini file on the SD card. This check determines if communication between the GPS and logger has been established. It also determines that the GPS unit that is attached matches the GPS_TYPE in the !quspin!.ini file. Finally, this check will not pass until the GPS unit has successfully found a fix. Depending on the location, a GPS fix can take up to 20 minutes even when you are outdoors. Attaching an external antenna can speed up this process.

Check 4: This check only occurs if the PPS_TIMESTAMP = true in the !quspin!.ini file on the SD card. This check determines that the logger is receiving a PPS signal from the GPS unit.

Check 5: This check only occurs if the MAGDATA_PULSE_TIMESTAMP = true in the !quspin!.ini file on the SD card. This check determines that the logger is receiving a Magdata pulse from the sensor. The sensor will only begin outputting a mag data pulse once it has achieved a lock.

Once the logger has passed its pre-arm checks successfully, it will move into a ready state, and logging is ready to be initiated. If LOG_AT_STARTUP = false in .ini file, the LED on the ACB will begin to blink blue. At this point, you can initiate logging through Bluetooth command ‘f’, or by pushing the blue button on the ACB. Make sure you are in ‘logger’ mode to initiate logging. The LED on the ACB will go to solid blue when it has begun logging. If LOG_AT_STARTUP = true in .ini file the logging will begin as soon as the pre-arm checks pass successfully.

Hint: If the pre-arm checks are not passing, connect to the Bluetooth to read out any errors (send command ‘A’ for ‘logger’ mode). The logger will continuously send updates via Bluetooth of the pre-arm check status.

The data log files saved to the SD card are in .txt format. Files will contain a verbatim dump of everything the QTFM and GPS transmits. Responses to commands, status messages, and star codes are timestamped and interleaved between mag data packets. If a GPS module is connected, enabled in the config file, and operational, then time and position data is also logged. The logging file format is chosen for the efficiency and reliability of logging but is not very convenient for viewing or analysis. For this reason, some post-processing of the log files is necessary before viewing the mag data, and a utility is provided for this purpose.

To view the log file(s)

Terminate logging by momentarily pressing the blue switch before removing the card
Remove SD card
Mount SD card on a PC
Locate and open the install folder for the QLogConverter application (C:/Users/Public/Public Documents/QuSpin Data). Drag and drop a log file (.txt) onto the QLogConverter.exe file (or a shortcut on your desktop). Three .csv file versions (comma-delimited) of the file will be created that are readable by Excel. A standard file will be generated in the QuSpinData folder. Also within the Quspin Data folder, there will be a folder called flatCSV which will contain a flat-file format, and a folder named geospatial, which will contain a geospatial format.

Once the files are in CSV format, another issue arises for large files: Excel’s maximum worksheet size of 1048576 (=2^20) rows by 16384 columns. QTFM logger can log very large files but they cannot be handled by Excel which can truncates them. For example, a log file size of ~54.2MB, corresponds to 4,169,230 records or spreadsheet rows, and Excel throws out the last 3M rows. Solutions, workarounds actually, to the problem of large CSV/xls files

To download the QLogConverter click here

QLogMonitorConsole app is available for download here

The QLogMonitorConsole app is a multifunctional tool designed to simplify your experience with the logger. Download files from the SD card to your PC without removing it, and they’ll be automatically formatted just like the QlogConverter does. Change the logger settings (without manually editing the !quspin!.ini fille), receive logger status updates, start and stop logging, and update the logger’s firmware, all within the app. To begin, connect a USB cable from your PC to the logger port and launch the QLogMonitorConsole app.

If your logger’s firmware is outdated, the QLogMonitorConsole app might not recognize it. In that case, you’ll need to manually update the logger firmware once before using the app. You can download the latest firmware here. Just download the folder to your PC, connect to the logger port, and run LoadLogger.bat to update the firmware. From then on, all future logger firmware updates can be easily handled within the QLogMonitorConsole app.

If the application isn’t functioning properly, please check the !quspin!.ini file on the SD card. Insert the SD card into your PC to access and modify the file as needed. Ensure that it matches the configuration below:

;Start
; configure QuSpin logger operation
[config] ;
USE_GPS = true
; PA1616D and PA6H set GPS_TYPE=1
; NEO-M8N set GPS_TYPE=2
; NEO-M9N set GPS_TYPE=3
; PA1616S set GPS_TYPE=4
GPS_TYPE=1
PPS_TIMESTAMP = true
MAGDATA_PULSE_TIMESTAMP = true
MAX_FILE_SIZE_BYTES = 671088630
LOG_AT_STARTUP = false
MAG_DATA_REPEATER = false
RADIO_RATE = 57600
DEMO_MODE = false

LOG_FILE_BINARY = false
GPS_RATE = 115200
FILE_NAME_PREFIX = TFM
SLAVE_PRESENT = false
;End

A more detailed QLogMonitorConsole App manual is available here