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Contents 1 1-Wire Wind Instrument 1.1 Packages 1.2 Components 1.3 Family codes 1.4 Connection 1.5 Links 1.6 Schematic diagram 1.7 Wind direction sensor 1.7.1 Orientation 1.7.1.1 Orientation according to the Java library 1.8 Wind speed sensor 1.9 Temperature sensor

1-Wire Wind Instrument

The 1-Wire Wind Instrument combines wind direction, wind speed and air temperature sensors. It was developed by Dallas Semiconductor and is currently sold by AAG.

Packages

The 1-Wire Wind Instrument has been included for sale in packages

• AAG TAI8515 1-Wire Weather Instrument Kit v.3.0, a.k.a. AAG 1-Wire Weather Station
• Dallas Semiconductor 1-Wire Weather Station (no longer sold)
• Texas Weather Instruments 1-Wire Weather Station

which also includes an RS-232/1-Wire adapter and other components.

Components

• The PCB in our unit is Dallas Semiconductor version 2.0 1999 but this does not mean that this is version 2.0 of the weather station.

• DS2423 4 kibibit 1-Wire RAM with counter (voor windsnelheidmeter)
• DS9502 ESD beveiliging diode
• DS2450 1-Wire quad A/D converter (voor windrichting)
• DS18S20 high-precision 1-Wire digital thermometer (voor temperatuur)

Family codes

• 1D Wind speed
• 10 Temperature
• 20 Wind direction

Connection

• Connection

Links

• Java APIs
  • Windsnelheid
  • Temperatuur
  • Windrichting
• Code examples
  • http://www.aagelectronica.com/Programas/tai-8515-sej-1.zip

Schematic diagram

The dual diode D2 (i.e., D2-A and D2-B) is not installed. Therefore, auxiliary power supplied on RJ jack pin #1 only powers the DS18S20 temperature sensor.

Wind direction sensor

After connecting the weather station to the 1-Wire network, the DS2450 needs to be configured (resolution and channel input). Then the conversion command needs to be sent in order to perform analog to digital conversion. Then the conversion result registers need to be read out.

Orientation

The following was figured out by examining the actual device.

In the diagram, direction #1 is labelled "N" but in practice the weather station can be mounted in any compass orientation; the numbered directions must be translated to geographical compass points in software by adding a direction offset.

The schematic diagram shows the component side of the circuit board.

When the weather station is installed, the component side of the circuit board faces down; hence, observed from above, the direction numbers increase clockwise around the circle.

When the circuit board is installed in its housing, direction #1 points directly away from the housing mount point.

Direction numbers correspond to ADC channel values in the following table in the sense that a magnet positioned in that direction number causes the given channels to have the given values. (The compass point given in the table is valid if direction #1 actually points north.)

number	compass	channel	level	levels
1	N	C	M	HHMH
2	NNE	BC	MM	HMMH
3	NE	B	M	HMHH
4	ENE	AB	MM	MMHH
5	E	A	M	MHHH
6	ESE	AD	ML	MHHL
7	SE	D	L	HHHL
8	SSE	CD	LL	HHLL
9	S	C	L	HHLH
10	SSW	BC	LL	HLLH
11	SW	B	L	HLHH
12	WSW	AB	LL	LLHH
13	W	A	L	LHHH
14	WNW	AD	LM	LHHM
15	NW	D	M	HHHM
16	NNW	CD	MM	HHMM

The vane is mounted on a shaft to which a magnet is mounted. The position of the magnet can be adjusted relative to the vane, but we will assume that the magnet is mounted in the direction opposite to that of the fin; i.e., it is mounted in the direction that the vane points, thus into the wind. Then the directions correspond to the ADC channels and levels given in the table. E.g., when the vane points in direction #1 is pulls ADC channel C down to medium voltage. The other channels remain at high voltage. When the vane points in direction #7 it pulls ADC channel D down to low voltage.

The RJ connectors are mounted on the non-circuit side of the circuit board. The pins of the RJ connector are furthest away from the board and thus are on the upper side.

Orientation according to the Java library

These values according to the Java example file are presented in the following table along with the compass points. In the third column we translate the terms used in the Java code (1,2,3,5) to the terms we use in the table above (L,M,H); we add the corresponding compass direction in the fourth column. This reveals that the Java code names compass points that are 45 degrees counterclockwise from ours.

Java lib		actual
value	direction	value	direction
5255	N	HMHH	NE
5335	NNW	HMMH	NNE
5525	NW	HHMH	N
5533	WNW	HHMM	NNW
5552	W	HHHM	NW
1552	WSW	LHHM	WNW
1555	SW	LHHH	W
1155	SSW	LLHH	WSW
5155	S	HLHH	SW
5115	SSE	HLLH	SSW
5515	SE	HHLH	S
5511	ESE	HHLL	SSE
5551	E	HHHL	SE
2551	ENE	MHHL	ESE
2555	NE	MHHH	E
3355	NNE	MMHH	ENE

Wind speed sensor

The wind speed sensor is based on a DS2423 counter which can be read through the "Read counter" high-level command on the HA7Net. This results in a count since the last reset. The speed in m/s can be calculated from this by dividing the count by the elapsed time in seconds since the last count. This needs to be multiplied by a calibration factor: 2.537492222.

Temperature sensor

The weather instrument also includes a temperature sensor, a DS18S20, which can be read through the high-level commands on the HA7Net:

• "Read DS18S20"
• "Read temperature"