WJ8888

14-09-2006

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Welcome

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Welcome to our site about the Watkins Johnson WJ8888/B2

This site is dedicated to our optocoupler interface which controls the WJ8888 by remote with Windows XP.

All electronics, designs, layouts, schematics and software codes remains property of Peter & Geert De Coninck.

the interface adds some new features to the radio receiver such as:
additional tuning with 100kHz, 1Mhz, 10MHz resolution
direct tuning with keypad
presets of frequencies
automatic up and downtuning of frequency with time interval
gain mode, if bw and detection mode fully controlable
extended memory to save radio settings
operating with RS232 or USB - RS232 converter

WJ8888 now also running with Windows Vista

last update February 2015

12-09-2006

Software

PC:

The entire Windows XP program is written in Borland C++ Enterprise 6.0.

Microcontroller:

The microcontroller firmware was written in BASCOM which is a Basic language based compiler for the Atmel microcontroller family. The machine code is programmed into the processor using the ABCEDIT software package.

http://www.mcselec.com/index.php?option=com_docman&task=cat_view&gid=99&Itemid=54

PCB Design and routing:

The PCB was entirely designed using the CAD software WinQCAD from Microcad.

11-09-2006

Hardware

The system consists of a synchronous communication board installed in the WJ8888/B2 receiver. This board is then connected by a special MIL connector to our optocoupler interface. Then it is connected by RS232 to the PC.

The hart of the interface is the ABC mini board with an Atmel AT90S8535 microcontroller mounted. The firmware in the microcontroller receives RS232 datapackages from PC and convert it to the 25kHz synchronous protocol used by the receiver. On command of the receiver the interface starts sending the datapackage.

Additional information about the Atmel family you can find here http://www.atmel.com/

10-09-2006

Radio Receiver

Here we give some active links to sites with lot of information about the WJ8888.

http://www.radiomuseum.org/r/watkins_wj_8888_wj8888.html

http://www.premium-rx.org/wj8888.htm

http://watkins-johnson.terryo.org/

09-09-2006

Receiver interface

The radio receiver is normally equiped with a 25kHz synchronous communication board.You can see a photograph of it right here.
The manufacturers part number of this board is 791200-1.

The synchronous communication is done by DS8820A and DS8830 IC's.

The DS7830 is a dual differential line driver that also performs the dual four-input NAND or dual four-input AND function.
TTL (Transistor-Transistor-Logic) multiple emitter inputs allow this line driver to interface with standard TTL systems. The differential outputs are balanced and are designed to drive long lengths of coaxial cable, strip line, or twisted pair transmission lines with characteristic impedances of 50Ohm to 500Ohm. The differential feature of the output eliminates troublesome ground-loop errors normally associated with single-wire transmissions.

The DS8820A is a digital line receiver with two completely independent units fabricated on a single silicon chip. Intended for use with digital systems connected by twisted pair lines, they have a differential input designed to reject large common mode signals while responding to small differential signals. The output is directly compatible with TTL or LS integrated circuits.

08-09-2006

Making of : preparing the 40 DIL on the ABC miniboard

Here we are preparing the ABC mini board on a 40 DIL socket.

07-09-2006

Making of 2 : preparing the photo-sensitive epoxy PCB

Ready for take off.
Here we are ready to fire some 300W UV ray's
onto a photo-sensitive epoxy PCB.

06-09-2006

Making of 3 : Peter etching the PCB

Just counting the minutes for etching the PCB,
in the kitchen....
Wife standing by in background, wondering whether husband is beyond
salvation ...

05-09-2006

Making of 4 : placing the components

Finally starting the real work.

04-09-2006

Making of 5 : finally done

The complete PCB. Only find that last component.

03-09-2006

You Tube 1 : 25kHz signals

Here you can find some animation of the protocol signals of the WJ8888 radio receiver.
The signals from the receiver are displayed on a Dynatec Oscilloscope 8120 (2x20MHz).
The first channel is the 25kHz clock signal received from the WJ8888 and the second channel
is the 64 bit wide dataword send from the WJ8888. Triggering was done on the first channel.
http://nl.youtube.com/watch?v=oyzgFfv6JnQ

Hopefull we get some more animations online soon.

05-08-2006

Screenshot 1 : PC software interface

Here you can see a screenshot of the PC software interface running under Windows XP. All important buttons and indications are grouped in one screen. Down at the screen you can find a LCD which displays all radio receiver settings in text format. Above the LCD you have the tuning resolution group. Please notice the additional resolutions 100kHz, 1MHz and 10MHz. At the right of the resolution group you find the selectors for IF bandwidth, gain mode and detection mode. There is also a keypad tuning feature for direct tuning. Settings for the RS232 protocol is also integrated into the main screen. At last there is a bit display which indicates binary patterns of the protocol data send to the receiver.

04-08-2006

Screenshot 2 : Start up screen

Start up screen

03-08-2006

Screenshot 3 : LCD Mini Monitor Mode

LCD Mini Monitor Mode pop up screen

02-08-2006

Screenshot 4 : Maxi Monitor Mode

Maxi Monitor Mode

01-08-2006

Screenshot 5 : TTL square wave analyzer

Here you can see a TTL square wave analyzer. This analyzer gives in realtime the status of the databits send to the receiver. The analyzer is included as a popup so you can call it as an overlay. Each databit in the protocol is graphical shown with low and high signals giving a 64 bit wide wave.

31-07-2006

System overview

This schematic gives an overview how the system works:

30-07-2006

Optocoupler interface

The interface is designed with optocouplers for optimal electrical insulation between receiver and PC.

29-07-2006

Microcontroller

We used an ABC mini board with 40 DIL package. The heart of this circuit is an Atmel AT90S8535. There are 32 user configurable I/O available giving us plenty of IO to do the job. Each I/O pin is software definable as input or output. On the board there is also a MAX232 IC
mounted so we can communicate with RS232 protocol. On the ABC mini board there is also an in circuit programming connector so we can program the microprocessor without disconnecting the board out of the circuit giving us more flexibility during debugging and maintenance.

28-07-2006

LCD

A 16x2 LCD screen is used for information about the internal signals of the microprocessor. You can follow in real time the information on the LCD. Also the LCD can dump additional information such as: radio settings, binary patterns, CRC checks, etc. In combination with the software TTL square wave analyzer this gives a lot of information about the actual status of the protocol. A special data led output is also available which gives the status of the databits send to the receiver.

Watkins Johnson WJ8888/B2 25kHz Optocoupler Interface

This site is not affiliated in any way with the Watkins Johnson company or DRS Technologies, the present owners of WJ Ga

Version 1.1 Alpha now fully operational!

Inhoud blog

	Welcome
	Software
	Hardware
	Radio Receiver
	Receiver interface
	Making of : preparing the 40 DIL on the ABC miniboard
	Making of 2 : preparing the photo-sensitive epoxy PCB
	Making of 3 : Peter etching the PCB
	Making of 4 : placing the components
	Making of 5 : finally done
	You Tube 1 : 25kHz signals
	Screenshot 1 : PC software interface
	Screenshot 2 : Start up screen
	Screenshot 3 : LCD Mini Monitor Mode
	Screenshot 4 : Maxi Monitor Mode
	Screenshot 5 : TTL square wave analyzer
	System overview
	Optocoupler interface
	Microcontroller
	LCD
	MIL Connector
	Testing
	Protocol
	Watkins Johnson History
	Lab
	Links
	Components
	Open source
	Schematics
	About us

'73

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