blemini_run.py

#!/usr/bin/env python3

#
# Copyright 2013-2021 Thomas Ackermann
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

#
# Read digital inputs from a RedBearLabs BLEmini. 
# BLEmini is a BLE (Bluetooth low energy) device so by
# automating gatttool with pexpect we are able to read and write values.
#
# Usage: blemini_test.py BLUETOOTH_ADR
#
# To find the address of your BLEmini run 'sudo hcitool lescan'
# To power up your bluetooth dongle run 'sudo hciconfig hci0 up'
#

#
# BLEMini Biscuit v2.0 handles
# (discovered by 'primary' resp. 'characteristic' cmd in gatttool):
#
# 0x12: read list of bytes transferred to BLEMini via serial connection
# 0x16: write byte to BLEMini to be received via serial connection
# 0x19: set baudrate for serial port (value is remanent; possible values are: 
#                      00=9600, 01=19200, 02=38400, 03=57600(default), 04=115200)
#

import os
import sys
import time
import random
import pexpect
from datetime import datetime

adr = sys.argv[1]

logdir = "/tmp/pihome"
try:
    os.mkdir(logdir)
except:
    pass

val = 0
exc = 0
act = 0
stamp = ""
handle = ""

def log_values():
    print(adr, " DATA 0x%02X, EXC %d, ACT %d" % (val, exc, act))
    print(adr, " STAMP '%s'" % stamp)

    data = open(logdir+"/"+adr, "w")
    data.write(" DATA 0x%02X\n" % val)
    data.write("EXCPT %d\n" % exc)
    data.write("ACTEX %d\n" % act)
    data.write("STAMP '%s'\n" % stamp)
    data.close()

while True:

    try:

        print(adr, " Trying to connect ...")

        tool = pexpect.spawn('gatttool -b ' + adr + ' --interactive', encoding='utf-8')
        tool.expect('\[LE\]>')
        tool.sendline('connect')
        tool.expect('success')

        # find handle
        cons = pexpect.run('hcitool con', encoding='utf-8')
        cons = cons.split("\r\n")
        for con in cons:
            if adr in con:
                tok = con.split()
                handle = tok[4]

        # set baudrate to 9600
        tool.sendline('char-write-cmd 0x19 00')
        tool.expect('\[LE\]>')

        while True:

            rnd = random.randint(0, 10)

            # send byte to BLEMini
            tool.sendline('char-write-cmd 0x16 ' + ("%02X" % rnd))
            tool.expect('\[LE\]>')
        
            # read byte/s from BLEMini
            tool.sendline('char-read-hnd 0x12')
            tool.expect('descriptor: .*? \r') 
            v = tool.after.split()
            val = int(float.fromhex(v[1]))

            stamp = datetime.now().ctime()
            act = 0

            log_values()

            #time.sleep(3600)
            time.sleep(300)

    except KeyboardInterrupt:
        tool.sendline('quit')
        tool.close()
        sys.exit()

    except:
        if handle != "":
            pexpect.run('sudo hcitool ledc ' + handle, encoding='utf-8')
        tool.sendline('quit')
        tool.close(force=True)
        exc = exc + 1
        act = 1