ferromagnetic
New member
This is taken from Dougs forum:http://groups.yahoo.com/group/ProspectinginOz/
He has granted permission on his forum to cross post stuff on the Pulse Devil.
HE PULSE DEVIL EXPLAINED: AN OVERVIEW
When designing a detector one is presented with a series of trade-offs. One such trade-off is the choice of how many user controls the detector will have.
Most designers have limited the number of user controls for two reasons.
The first reason is that many users don't like the idea of adjusting an instrument panel rivaling that found in the cockpit of a jet fighter.
The other reason, though less obvious, is just as important. The controls take up space. This means that the control box gets both bigger and heavier. Large control boxes and lot of controls also make the detector expensive.
To complicate things still further, the designer is faced with the fact that there are professional detector users in many parts of the world.
Some professionals seek ancient coins in Europe while others seek relics from various sites before they rot away and are lost for ever.
Still others are beating around the bush in Australia with a cold pack of tinnies on their back looking for the big one!!!
The professional user wants to get everything they can from their detector. Such a person will spend the time to learn how to adjust any number of controls available to them in order to squeeze out those extra, all important few inches of depth.
The truth is that a detector with a full complement of controls is potentially far more powerful than a detector equipped with a limited number of controls.
The challenge was to make a detector which suited everyone. A detector which could be effectively used by a either a beginner or a professional.
I decided that a make-over was in order.
The first order of business was to replace the Nickel Metal Hydride (NiMH) battery pack with a powerful Lithium Ion (Li-ion) type. The new pack is much lighter than the old one which made for a good start.
I removed all the mechanical controls and mechanical switches from the Pulse Devil and replaced them all with tiny electronic chip pots. The chip pots are adjusted by one of two on board microcomputer chips.
The removal of the mechanical controls and switches provided a control box front panel which sports only an LCD display and a single control knob.
USING THE DETECTOR
The single knob is mounted on the master control. This control knob can be turned clockwise or counterclockwise. The control knob can also be pushed in to actuate a built in momentary switch.
TURNING THE DETECTOR ON AND OFF
Pressing the knob in causes the LCD to display a message requesting that you enter a PIN number.
The numbers 0 - 9 are displayed in a row followed by the word "ENTER".
Turning the control knob causes each number to flash on and off in turn as the knob is rotated. As an example, the operator used the last five digits of his drivers license number for his PIN code. the PIN number is 28217.
To enter this, one simply rotates the control knob until the "2" flashes. Pressing the knob in will now enter the number and cause a * to be displayed on the bottom line of the display. The control knob is now rotated to where the "8" flashes. Pressing the knob in enters the number and causes the bottom line of the display to **.
The rest of the numbers are now entered until the bottom line displays *****
The knob is now rotated to the word "ENTER". The knob is pressed in and the PIN code is entered.
The detector can now be switched on and off as many times as is required for a period of 48 hours. This will render stolen Pulse Devils useless to a thief. There is, of course, a factory back door code in case anyone forgets their PIN number. The detector can be reset upon verification of ownership.
Once the detector is turned on the main menu is displayed. The menu has the following options which appear one at a time by rotating the control knob:
"Operate"
"Default Settings"
"Manual Settings"
"Stored Settings"
"Shutdown"
The option is selected by pressing the control knob in.
OPERATE MODE
Selecting the "operate" mode reloads the control settings which were in place when the detector was last switched off. You are all ready to detect.
DEFAULT SETTINGS
Selecting "Default Settings" provides a large number of factory preset control settings for different types of detecting such as "Prospecting", "Relic Hunting", "Coin Hunting", "Beach Hunting" and conditions such as "Neutral Ground" "Mineral Ground" "Extreme Ground" and "Salt Ground".
The default settings offer a starting point to set the detectors controls.
MANUAL SETTINGS
Selecting "Manual Settings" allows the user to select and change any or all of the detectors controls and settings.
Here is the list of the user accessible controls on the PD.
Threshold,
Ground Balance,
RX Gain, (similar to sensitivity)
Automatic Retune Speed,
Discrimination,
Audio Tone,
Audio Volume,
Sample Delay,
Noise Tuning (adjusts out interference by varying the operating frequency),
Display Backlight (setting can be set from OFF to full brightness in steps),
Automatic or Non Automatic Tuning Select (ON - OFF),
Transmit Pulse Width Selection:
250us
500us
750us
1000us
ON-OFF POWER SWITCHING
There is also a Battery Voltage display which displays the battery voltage with a resolution of 0.1 Volts.
STORED SETTINGS
Selecting the "Stored Settings" allows the user to store the detectors current settings along with a simple name tag for use on a future return trip. The detector can store dozens of these stored settings.
A note pad memory is also provided for the user to enter the GPS location next to the name tag. This allows the instant recall and loading of all the detectors settings for any particular site.
The detector's settings are stored automatically when the detector is told to shutdown. Turning the detector back on reloads these settings.
The memory's used are all non volatile types. The will store their data
without a battery being installed in the detector.
SHUTDOWN
The Pulse Devil uses a software shutdown. Selecting "Shutdown" causes the detector to load its settings into memory and then shut off the power from the battery via an electronic switch.
An audio low battery alert sounds a sharp beep once every thirty seconds until the critical battery voltage is reached and the detector shuts down to avoid over discharging of the battery pack.
The Pulse Devil has a built-in battery charger. An AC cord and a car cigarette lighter cord / plug provide charging from 90VAC to 240VAC 50/60Hz or a 12VDC to 24VDC vehicle battery.
The battery pack can be charged in place or simply replaced in the field.
For the European or the deluxe versions, there is also a Target ID or TID.
The LCD display now displays the target ID in super large, easy-to-read
numbers. The number is negative for ferrous and positive for non ferrous.
The TID provides the same number for the same type of target just as the TID circuits found on many high end VLF detectors do. The TID is quite accurate.
As a final note, the Pulse Devil in the picture that is posted on the forum does not have the graphics on it as the production model will.
Here is an explanation of some of the Pulse Devil's features. This
explanation is not to be considered as a part of an operating manual.
It is only an explanation of some of the features.
PULSE DEVIL: ADDITIONAL INFORMATION
DISCRIMINATION
All versions of the Pulse Devil come equipped with a full range
discrimination control. This control, although set digitally,
operates in exactly the same way as a discrimination control on a VLF.
For prospecting a full range, discrimination is not useful. The only
discrimination required is one that provides a ferrous - nonferrous
indication.
The full range discrimination control is provided to allow the
detector to be used for coin and relic hunting in addition to its use
in prospecting.
The discrimination control settings start at iron rejection and goes
to foil rejection and then all the way up to pulltab rejection.
The Pulse Devil can be upgraded by the dealer to include a Target ID
or "TID". The European version of the Pulse Devil is designed
primarily as a coin and relic detector — the TID is included on this
model.
The TID will output a negative number for a ferrous target and a
positive number for a nonferrous target.
Each type of target will provide a different number.
The numbers are a measure of the targets conductivity.
Low conductivity targets such as cupro nickel coins will provide a
low number such as +50 while a high conductivity target such as a
silver coin will provide a higher number such as +180.
The numbers displayed in TID mode are much taller and easier to read
than the characters in other modes. Each number takes up the entire
display height
NOTE: The dealer can also change the display for left handed
operation. This is accomplished by turning the display 180 degrees.
Left hand Pulse Devils will have their master control knob on the
right of the control panel while right hand Pulse Devils will have
their master control knob on the left.
PULSE WIDTH SELECTION
There are four selectable transmit pulse widths. These are 250us,
500us, 750us and 1000us. Almost all other PI detectors use transmit
pulse widths of between 50us and 250us. Some use both long and short
pulses. The maximum pulse widths used are on the order of 250us. (us
= microseconds or millionth parts of a second).
Each type of target has what is called a time constant or "TC". This
is a measure of the time it takes the received signal to decline in
voltage from its peak value to a low value.
Small gold nuggets can easily have a TC as low as 15 microseconds
while a large silver coin might have a TC of many hundreds of
microseconds.
In order to achieve a maximum detection depth on a target, the width
or length of the transmit pulse should ideally be long for long TC
targets.
A target such as a small gold nugget can be detected at maximum depth
using a transmit pulse which is much shorter. Using a long pulse on a
target with a short TC will neither increase or decrease the
detection range.
The selection of the pulse width is now dependent on the type of
target that is being sought. In an area where only small gold has
ever been found the 250us setting is ample. Conversely, if the area
has produced large gold then it is safer to use a longer pulse width.
The highest pulse widths are required when searching for large highly
conductive targets such as large silver items.
Using longer transmit pulses causes the battery to be drained faster
than when shorter transmit pulses are used. This is the reason that a
selection of pulse widths has been provided.
GROUND ADJUST
The ground adjust control is used the same way as the ground adjust
or ground balance controls on many VLF detectors. The searchcoil is
simply lowered toward the ground from an initial height of two to
three feet or 60 - 90 cms.
If the audio level increases, the control is turned counterclockwise.
If the audio level decreases, then the control is turned clockwise.
The detector is tuned to the ground when the change in the audio
level is the least when the searchcoil is raised and lowered.
AUTOMATIC TUNING
The retune speed of the Pulse Devil can be adjusted from a super slow
speed of 25 seconds to a super fast speed of 1 second.
There are two different tuning modes provided. A regular automatic
tuning or a zero overshoot constant threshold tuning is user selectable.
The tuning speed is selected for the users preference or to minimize
any ground noise due to rapid variations in the mineral make up of
the soil.
MORE TO COME
Dave
He has granted permission on his forum to cross post stuff on the Pulse Devil.
HE PULSE DEVIL EXPLAINED: AN OVERVIEW
When designing a detector one is presented with a series of trade-offs. One such trade-off is the choice of how many user controls the detector will have.
Most designers have limited the number of user controls for two reasons.
The first reason is that many users don't like the idea of adjusting an instrument panel rivaling that found in the cockpit of a jet fighter.
The other reason, though less obvious, is just as important. The controls take up space. This means that the control box gets both bigger and heavier. Large control boxes and lot of controls also make the detector expensive.
To complicate things still further, the designer is faced with the fact that there are professional detector users in many parts of the world.
Some professionals seek ancient coins in Europe while others seek relics from various sites before they rot away and are lost for ever.
Still others are beating around the bush in Australia with a cold pack of tinnies on their back looking for the big one!!!
The professional user wants to get everything they can from their detector. Such a person will spend the time to learn how to adjust any number of controls available to them in order to squeeze out those extra, all important few inches of depth.
The truth is that a detector with a full complement of controls is potentially far more powerful than a detector equipped with a limited number of controls.
The challenge was to make a detector which suited everyone. A detector which could be effectively used by a either a beginner or a professional.
I decided that a make-over was in order.
The first order of business was to replace the Nickel Metal Hydride (NiMH) battery pack with a powerful Lithium Ion (Li-ion) type. The new pack is much lighter than the old one which made for a good start.
I removed all the mechanical controls and mechanical switches from the Pulse Devil and replaced them all with tiny electronic chip pots. The chip pots are adjusted by one of two on board microcomputer chips.
The removal of the mechanical controls and switches provided a control box front panel which sports only an LCD display and a single control knob.
USING THE DETECTOR
The single knob is mounted on the master control. This control knob can be turned clockwise or counterclockwise. The control knob can also be pushed in to actuate a built in momentary switch.
TURNING THE DETECTOR ON AND OFF
Pressing the knob in causes the LCD to display a message requesting that you enter a PIN number.
The numbers 0 - 9 are displayed in a row followed by the word "ENTER".
Turning the control knob causes each number to flash on and off in turn as the knob is rotated. As an example, the operator used the last five digits of his drivers license number for his PIN code. the PIN number is 28217.
To enter this, one simply rotates the control knob until the "2" flashes. Pressing the knob in will now enter the number and cause a * to be displayed on the bottom line of the display. The control knob is now rotated to where the "8" flashes. Pressing the knob in enters the number and causes the bottom line of the display to **.
The rest of the numbers are now entered until the bottom line displays *****
The knob is now rotated to the word "ENTER". The knob is pressed in and the PIN code is entered.
The detector can now be switched on and off as many times as is required for a period of 48 hours. This will render stolen Pulse Devils useless to a thief. There is, of course, a factory back door code in case anyone forgets their PIN number. The detector can be reset upon verification of ownership.
Once the detector is turned on the main menu is displayed. The menu has the following options which appear one at a time by rotating the control knob:
"Operate"
"Default Settings"
"Manual Settings"
"Stored Settings"
"Shutdown"
The option is selected by pressing the control knob in.
OPERATE MODE
Selecting the "operate" mode reloads the control settings which were in place when the detector was last switched off. You are all ready to detect.
DEFAULT SETTINGS
Selecting "Default Settings" provides a large number of factory preset control settings for different types of detecting such as "Prospecting", "Relic Hunting", "Coin Hunting", "Beach Hunting" and conditions such as "Neutral Ground" "Mineral Ground" "Extreme Ground" and "Salt Ground".
The default settings offer a starting point to set the detectors controls.
MANUAL SETTINGS
Selecting "Manual Settings" allows the user to select and change any or all of the detectors controls and settings.
Here is the list of the user accessible controls on the PD.
Threshold,
Ground Balance,
RX Gain, (similar to sensitivity)
Automatic Retune Speed,
Discrimination,
Audio Tone,
Audio Volume,
Sample Delay,
Noise Tuning (adjusts out interference by varying the operating frequency),
Display Backlight (setting can be set from OFF to full brightness in steps),
Automatic or Non Automatic Tuning Select (ON - OFF),
Transmit Pulse Width Selection:
250us
500us
750us
1000us
ON-OFF POWER SWITCHING
There is also a Battery Voltage display which displays the battery voltage with a resolution of 0.1 Volts.
STORED SETTINGS
Selecting the "Stored Settings" allows the user to store the detectors current settings along with a simple name tag for use on a future return trip. The detector can store dozens of these stored settings.
A note pad memory is also provided for the user to enter the GPS location next to the name tag. This allows the instant recall and loading of all the detectors settings for any particular site.
The detector's settings are stored automatically when the detector is told to shutdown. Turning the detector back on reloads these settings.
The memory's used are all non volatile types. The will store their data
without a battery being installed in the detector.
SHUTDOWN
The Pulse Devil uses a software shutdown. Selecting "Shutdown" causes the detector to load its settings into memory and then shut off the power from the battery via an electronic switch.
An audio low battery alert sounds a sharp beep once every thirty seconds until the critical battery voltage is reached and the detector shuts down to avoid over discharging of the battery pack.
The Pulse Devil has a built-in battery charger. An AC cord and a car cigarette lighter cord / plug provide charging from 90VAC to 240VAC 50/60Hz or a 12VDC to 24VDC vehicle battery.
The battery pack can be charged in place or simply replaced in the field.
For the European or the deluxe versions, there is also a Target ID or TID.
The LCD display now displays the target ID in super large, easy-to-read
numbers. The number is negative for ferrous and positive for non ferrous.
The TID provides the same number for the same type of target just as the TID circuits found on many high end VLF detectors do. The TID is quite accurate.
As a final note, the Pulse Devil in the picture that is posted on the forum does not have the graphics on it as the production model will.
Here is an explanation of some of the Pulse Devil's features. This
explanation is not to be considered as a part of an operating manual.
It is only an explanation of some of the features.
PULSE DEVIL: ADDITIONAL INFORMATION
DISCRIMINATION
All versions of the Pulse Devil come equipped with a full range
discrimination control. This control, although set digitally,
operates in exactly the same way as a discrimination control on a VLF.
For prospecting a full range, discrimination is not useful. The only
discrimination required is one that provides a ferrous - nonferrous
indication.
The full range discrimination control is provided to allow the
detector to be used for coin and relic hunting in addition to its use
in prospecting.
The discrimination control settings start at iron rejection and goes
to foil rejection and then all the way up to pulltab rejection.
The Pulse Devil can be upgraded by the dealer to include a Target ID
or "TID". The European version of the Pulse Devil is designed
primarily as a coin and relic detector — the TID is included on this
model.
The TID will output a negative number for a ferrous target and a
positive number for a nonferrous target.
Each type of target will provide a different number.
The numbers are a measure of the targets conductivity.
Low conductivity targets such as cupro nickel coins will provide a
low number such as +50 while a high conductivity target such as a
silver coin will provide a higher number such as +180.
The numbers displayed in TID mode are much taller and easier to read
than the characters in other modes. Each number takes up the entire
display height
NOTE: The dealer can also change the display for left handed
operation. This is accomplished by turning the display 180 degrees.
Left hand Pulse Devils will have their master control knob on the
right of the control panel while right hand Pulse Devils will have
their master control knob on the left.
PULSE WIDTH SELECTION
There are four selectable transmit pulse widths. These are 250us,
500us, 750us and 1000us. Almost all other PI detectors use transmit
pulse widths of between 50us and 250us. Some use both long and short
pulses. The maximum pulse widths used are on the order of 250us. (us
= microseconds or millionth parts of a second).
Each type of target has what is called a time constant or "TC". This
is a measure of the time it takes the received signal to decline in
voltage from its peak value to a low value.
Small gold nuggets can easily have a TC as low as 15 microseconds
while a large silver coin might have a TC of many hundreds of
microseconds.
In order to achieve a maximum detection depth on a target, the width
or length of the transmit pulse should ideally be long for long TC
targets.
A target such as a small gold nugget can be detected at maximum depth
using a transmit pulse which is much shorter. Using a long pulse on a
target with a short TC will neither increase or decrease the
detection range.
The selection of the pulse width is now dependent on the type of
target that is being sought. In an area where only small gold has
ever been found the 250us setting is ample. Conversely, if the area
has produced large gold then it is safer to use a longer pulse width.
The highest pulse widths are required when searching for large highly
conductive targets such as large silver items.
Using longer transmit pulses causes the battery to be drained faster
than when shorter transmit pulses are used. This is the reason that a
selection of pulse widths has been provided.
GROUND ADJUST
The ground adjust control is used the same way as the ground adjust
or ground balance controls on many VLF detectors. The searchcoil is
simply lowered toward the ground from an initial height of two to
three feet or 60 - 90 cms.
If the audio level increases, the control is turned counterclockwise.
If the audio level decreases, then the control is turned clockwise.
The detector is tuned to the ground when the change in the audio
level is the least when the searchcoil is raised and lowered.
AUTOMATIC TUNING
The retune speed of the Pulse Devil can be adjusted from a super slow
speed of 25 seconds to a super fast speed of 1 second.
There are two different tuning modes provided. A regular automatic
tuning or a zero overshoot constant threshold tuning is user selectable.
The tuning speed is selected for the users preference or to minimize
any ground noise due to rapid variations in the mineral make up of
the soil.
MORE TO COME
Dave
