Pyscan

This chapter describes the various libraries which are designed for the Pyscan board. This includes details about the various methods and classes available for each of the Pyscan’s sensors.

3-Axis Accelerometer (LIS2HH12)

Pysense has a 3-Axis Accelerometer that provides outputs for acceleration as well as roll, pitch and yaw.

Constructors

class LIS2HH12(pysense = None, sda = 'P22', scl = 'P21')

Creates a LIS2HH12 object, that will return values for acceleration, roll, pitch and yaw. Constructor must be passed a Pysense or I2C object to successfully construct.

Methods

LIS2HH12.acceleration()

Read the acceleration from the LIS2HH12. Returns a tuple with the 3 values of acceleration (G).

LIS2HH12.roll()

Read the current roll from the LIS2HH12. Returns a float in degrees in the range -180 to 180.

LIS2HH12.pitch()

Read the current pitch from the LIS2HH12. Returns a float in degrees in the range -90 to 90. Once the board tilts beyond this range the values will repeat. This is due to a lack of yaw measurement, making it not possible to know the exact orientation of the board.

Digital Ambient Light Sensor (LTR-329ALS-01)

Pysense has a dual light sensor that provides outputs for external light levels in lux. See the datasheet for more information about the wavelengths of the two sensors.

Constructors

class LTR329ALS01(pysense = None, sda = 'P22', scl = 'P21', gain = ALS_GAIN_1X, integration = ALS_INT_100, rate = ALS_RATE_500)

Creates a LTR329ALS01 object, that will return values for light in lux. Constructor must be passed a Pysense or I2C object to successfully construct.

Methods

LTR329ALS01.light()

Read the light levels of both LTR329ALS01 sensors. Returns a tuple with two values for light levels in lux.

Arguments

The following arguments may be passed into the constructor.

• gain: ALS_GAIN_1X,ALS_GAIN_2X, ALS_GAIN_4X, ALS_GAIN_8X, ALS_GAIN_48X, ALS_GAIN_96X
• integration: ALS_INT_50, ALS_INT_100, ALS_INT_150, ALS_INT_200, ALS_INT_250, ALS_INT_300, ALS_INT_350, ALS_INT_400
• rate: ALS_RATE_50, ALS_RATE_100, ALS_RATE_200, ALS_RATE_500, ALS_RATE_1000, ALS_RATE_2000

Pyscan NFC library (MFRC6300)

Constructors

class MFRC630(pyscan=None, sda='P22', scl='P21', timeout=None, debug=False)

Creates a MFRC630 object. Constructor must be passed a Pyscan or I2C object to successfully construct.

Methods

MFRC630.mfrc630_cmd_init()

Initialise the MFRC630 with some settings

MFRC630.mfrc630_cmd_reset()

Reset the device. Stops the currently active command and resets device.

MFRC630.mfrc630_cmd_idle()

Set the device into idle mode. Stops the currently active command and return to idle mode.

MFRC630.mfrc630_cmd_load_key(key)

Loads the provided key into the key buffer.

• key Array which holds the MIFARE key, it is always 6 bytes long

MFRC630.mfrc630_MF_read_block(block_address, dest)

Reads a block of memory from an authenticated card. Try to read a block of memory from the card with the appropriate timeouts and error checking.

• block_address The block to read
• dest The array in which to write the 16 bytes read from the card

Returns 0 for failure, otherwise the number of bytes received.

MFRC630.mfrc630_MF_auth(uid, key_type, block)

Perform a MIFARE authentication procedure. This function is a higher-level wrapper around the MF authenticate command. The result of the authentication is checked to identify whether it appears to have succeeded. The key must be loaded into the key buffer with MFRC630.mfrc630_cmd_load_key(key).

Once authenticated, the authentication MUST be stopped manually by calling the mfrc630_MF_deauth() function or otherwise disabling the Crypto1 ON bit in the status register.

• key_type The MIFARE key A or B (MFRC630_MF_AUTH_KEY_A or MFRC630_MF_AUTH_KEY_B) to use
• block The block to authenticate
• uid The authentication procedure required the first four bytes of the card's UID to authenticate

Returns 0 in case of failure, nonzero in case of success.

MFRC630.mfrc630_MF_deauth()

Disables MIFARE authentication. Disable the Crypto1 bit from the status register to disable encryption.

MFRC630.mfrc630_iso14443a_WUPA_REQA(instruction)

Send WUPA and REQA. Returns the response byte, the answer to request A byte (ATQA), or 0 in case of no answer.

• instruction: MFRC630_ISO14443_CMD_WUPA, MFRC630_ISO14443_CMD_REQA

MFRC630.mfrc630_iso14443a_select(uid)

Performs the SELECT procedure to discover a card's UID. This performs the SELECT procedure as explained in ISO14443A, this determines the UID of the card, if multiple cards are present, a collision will occur, which is handled according to the norm.

• uid: The UID of the card will be stored into this array.

Returns the length of the UID in bytes (4, 7, 10), or 0 in case of failure.

MFRC630.print_debug(msg)

Prints debug statements if DEBUG is enabled.

MFRC630.format_block(block, length)

Prints block with length.

MFRC630.mfrc630_format_block(data, len)

Converts data to hexadecimal format.

• data The array to be formatted
• len The number of bytes to format

MFRC630.mfrc630_print_block(data, len)

Prints the bytes in data array in hexadecimal format, separated by spaces using the mfrc630_format_block method.

• data The array to be printed
• len The number of bytes to print