The greenhouse project

Logger

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The logger

The logger is the main component in the project. It can be used stand-alone, connected to a PC or via radio (one-way at the time). In stand-alone mode it will log all measurements in the BX24 EEPROM. Its "logging program" specifies what to log. To save memory you may also specify the accuracy you want. This is a list of what can be measured/logged.

• Date and time (any combination of YYMMDDHHMMSS) - 1 to 6 bytes
• State of I/O pins - 1 byte
• Temperature -50 to +125 degrees C with 0.5 degrees accuracy (full or integer) - 1 or 2 bytes
• Internal AD 10 bits (10 or 8 bits accuracy) - 1 or 2 bytes
• External AD 12 bits (12 or 8 bits accuracy) - 1 or 2 bytes (See note 1)

Note 1: One of the AD pins is connected to the onboard battery and another to the external power source (divided by four).

The result of each item can be directed to the serial port and transmitter and/or to the EEPROM.

In addition to the measurements the time when the logger is turned on (or restarted) will be logged. It will also log the time it's turned off (or hangs, being reset etc.). This can be used in a solar powered operation to know exactly how long the batteries lasted before the sun comes back.

The measuring start time is set as a full date/time value. Wildcards are allowed to say, for example Start at midnight, any night, defined as X X X 0 0 0. The interval between measurements is defined by another full date/time value, down to one second.

1. BX24
2. Serial/download port
3. MAX232 V24 interface (not used)
4. TX module connector
5. RX module connector
6. DS1307 Clock circuit and its NiMH battery
7. MAX186 AD-converter 8 channel 12 bits (used but will be removed)
8. Connectors to roof sensors
9. DS1621 Thermometer -55 to +125 degrees C
10. 24FC65 8kB EEPROM (not used)