Self made data-logger
Self made data-logger
The new data-logger softw1are is not yet completely finished.
But the hardware design is frozen and will probably not be changed anymore.
The printed circuit board is a bit smaller than the old one (36x22mm).
But unfortunately the new one can measure analog input signals only with 10 bit resolution.
The sensor for barometric altitude and its amplifier are contained on the printed circuit board now.
Since the dissolution of altitude (10 bit) is too rough for the climb rate, an additional circuit is on the board.
An amplifier for current measurements as well as an amplifier for measuring bridges are likewise contained on the board.
Thus only an additional shunt or a measuring bridge (e.g. a differential pressure sensor with pitot tube) needs to be attached.
The measured data can be stored in a EEPROM and / or transferred by telemetry or by cable to a PalmPilot or PC.
The baud rate for the telemetry mode is selectable. 1200 and 9600 baud are available.
The data rate for the transfere of the the stored data to the Palm / PC was increased to 38400 baud.
Version V2.5 are different to version V2.4 in case of the circuit for current measurement. Therefore BEC-systems can used now.
Version V2.9 supports also GPS-receiver with ANTARIS chipset and simultaneously using of internal temperature sensor of MS5534A and external DS1820 sensor. This version can use 24C256, 24C512 or 24C1024 EEPROMs and has an internal `bootloader` implemented.
With V2.9g you can configure the datalogger for the `Multilogging mode` (more than one loggs possible after switch off).
V2.9h supports DS18S20 temperature sensors, 2-wire connection for the temp sensor (connect pin1 and 3 of the sensor) and better start condition for GPS using.
Additional sensors:
Following a modified circuit for the current measurement:
Digital pressure sensor:
Instead of the analog pressure sensor MPX4100 you can now connect a combined pressure and temperature sensor MS5534A.
The connectors which are normaly used by the additional LTC2400 and the connector for the analog variometer signal are used then.
The benefit of this sensor is the larger range (300...1100mbar) and the calibration.
Attention: To use this sensor the reference voltage must adjust to 3.3 ... 3.6V (R1, R2).
Besides the sensor must be registered to the logger (use the "Loggerleserprogram" for this reason).
Manchester-2 to RS232 Decoder
This decoder is necessary if the bi-phase-code (Manchester-2-code) is used by the telemetry. This feature is configurable by the "Logerleserprogram".
The decoder is installed after the telemetry receiver and transform the Man-2-code to the normally used RS232-code for the PC or Palm.
The adjustable resistor adjust the threshold for the used data.The led show if the treshold is exeeded.
If RSSI is not available on the receiver then pin6 of the PIC12F629 must be connected to pin1.
Layout for Telemetry-Decoder
The softw1are is in the development phase and can measure only the following signals at the moment.
5 analog channels (4x 10 bit, 1x 8 bit)
1 period duration input, for number of revolutions, speed etc. (16bit, pin 21)
1 frequency input for speed etc. (16bit, pin 6)
1 temperature input (8Bit, DS1820, Pin11)
3 RC channel inputs (additional 1 RC channel for switching the logger ON and OFF, RC0)
In place of the RC channels, the digital outputs of a ADXL202 (acceleration-sensor) can be used.
GPS (longitude, latitude and altitude), 38400 baud NMEA interface used
Simple vario tone output (pin 13)
Additionally it`s possible to use a 24 bit analog digital converter (LTC-2400) for more accuracy.
Telemetry data can be transmitted by using Manchester-2-code or RS232 format.
Version V2.9 has an internal `Bootloader` for easier softw1are updates via the RS232-connection (without PIC-burner). (For upgrades connect pin 5 and pin1 of the EEPROM with a 220ohm-resistor and switch the logger on).
Automatically recognize of the used EEPROM 24C256 / 24C512 / 24C1024.
With version V2.9g you can use the datalogger for more than one flight also after switch of the power of the datalogger.
