SEKHMET Digital Gauge Owner's Manual

Introduction

The SEKHMET Digital Gauge is presented as the gold standard for air gun gauges, offering significantly higher accuracy than analog gauges. It functions as a multi-functional mini-computer for airgun enthusiasts.

1. First Time Use

Upon unpacking, charge the gauge using the provided USB cable for at least 20 minutes. The USB cable is located at the bottom of the packaging.

A full charge from zero battery takes one hour. The battery lasts for 10 hours if the screen remains on. In most cases, the gauge operates with a black screen or in sleep mode, allowing for recharging once every one to two months depending on usage frequency. The battery life can extend up to 300 days on a single charge under minimal use.

Charging Indicator: To initiate charging, align the charging pins on the gauge with the charging port. The charging icon will appear on the display to confirm a good connection. Remember to remove any protective covers before charging.

To check the current battery level, tap the Middle Key to wake the gauge. If it shows 0 bar, touch and hold the Middle Key. An introduction video is available via a provided link.

2. Install

2.1 Seal Component: Before installing the gauge on your air gun, select the appropriate seal component. The complimentary Bonded Seal is recommended. Using Pom/Teflon/Rubber gaskets might block the air inlet if over-tightened, potentially causing the gauge to read ZERO. Ensure the air inlet is clear.

2.2 Installation: Place the seal on the thread and then install the gauge onto your rifle. The seal functions between the gauge and rifle, creating a seal. A diagram illustrates this, showing a bolt with an outer annular ring of hard material and an inner annular ring of soft material.

2.3 POM Seal Note: If a POM seal is already in use on your rifle, the washer should not be installed.

3. Display & Modes

Access the menu by touching the middle key. After waking the gauge, long-touch the right/left touch key in the main interface to navigate.

3.1 Simple Mode: The main interface displays the current pressure and the number of shots in the upper right corner. The gauge counts shots by detecting pressure drops. If placed on a regulator, it will only display regulator pressure and cannot count shots; shot counting requires the gauge to be on the bottle/main chamber.

3.1.1 Shot Count Logic: Temperature drops after filling can contribute to the shot count. If excessive data is recorded or counting errors occur, the screen may display gibberish. For instance, '15' under '139' might indicate 1015 data entries. Clearing data is recommended in such cases.

3.1.2 Clearing Shot Count: Two methods exist to clear the number of shots:

Combination Key: In the pressure display, touch and hold the Middle key, then touch the Right key. This function is only active in pressure display.
Filling: Filling the reservoir with pressure exceeding 30 bars in one go can also clear the count.

3.1.3 Regulator Gauge Limitation: Due to these factors, a regulator gauge may only read pressure without counting shots.

3.2 Pro Mode: Switch from Simple mode in the menu to access three additional displays: Shot Left, Last Shot Pressure Drop, and Average Pressure Drop.

3.2.1 LEFT SHOT: Displays remaining shots.
3.2.2 <<: Indicates last air consumption.
3.2.3 AVG: Shows average air consumption.

3.3 Regulator Mode: Recommended when the gauge is attached to a regulator. In this mode, shot count and data clearing via pressure rise are disabled. It shows current pressure and does not cycle through different screens. The key difference from Simple mode is the Filter Function, designed to provide a stable display for the rapidly changing pressure within a regulator chamber. Using Simple mode with a regulator might lead to display issues.

4. Functions in the Menu

The menu offers various functions:

4.1 Fill wake up: Allows the gauge to detect pressure rise and turn on the screen when powered. This function does not extend battery life after power off. Filling with a hand pump or small pump that fills the gun slowly may not trigger this feature.
4.2 Power Off: Sets auto-shutdown time; any operation resets the countdown.
4.3 Screen Off: Configures auto display turn-off time; any operation resets the countdown.
4.4 Data Clear: Clears the shot counts.
4.5 P-minimum: Manually input a regulator pressure to calculate remaining shots based on main reservoir pressure; applicable only to the main reservoir gauge.
4.6 Rotate Screen: Rotates the display 180 degrees to adjust for different installation angles.
4.7 Wake by Shot: Detects pressure drops to turn on the screen when the device is powered. It does not extend battery life after power off but can be triggered by a slow leak.
4.8 Device Info: Displays the current software version.
4.9 Temperature: Enables the temperature display.
4.10 Temp Unit: Allows switching between Fahrenheit (°F) and Celsius (°C).
4.11 Cal Temp: Enables calibration of the sensor temperature by entering the current ambient temperature. Calibration might be inaccurate if the gauge was recently used due to gas temperature variations.

5. Software Update

Before upgrading, check the current software version via the 'Info' option in the menu. Software for the 28mm pressure gauge is available in Series A and Series B, which are upgradeable within their series but not between series. Series A and B use different control chips but offer identical functions.

Ensure your gauge is at least Version 4.36.

Preparations for Upgrade:

SEKHMET Digital Gauge (at least V4.36)
USB Update Tool
PC with Windows OS
SEKHMET Upgrade Program
New software

Software can be downloaded from: https://www.sekhmetonline.com/products/28mm-digital-gauge-usb-firmware-updater

After downloading, unpack the software and install the CH341 driver. The driver for Windows 10 is available via a provided link.

Update Process:

Open AVRDUDESS software. Import the appropriate preset file (e.g., 'SEKHMET_presets.xml') based on your software series. Select the latest version of the pressure gauge program in .hex format. The software will prompt for file loading.

Insert the USB Update Tool into your computer and select the corresponding COM port in AVRDUDESS. Connect the gauge to the updater, aligning the USB Update Tool tip with the gauge, and hold until the charging icon appears, indicating good contact.

Click 'Program' in AVRDUDESS. A progress bar indicates successful completion. Wait for the progress bar to finish, confirming the burning process is successful.

A YouTube video is available for guidance before updating: https://www.youtube.com/watch?v=n2bHGe7Japc

6. Notices

6.1 Stuck/Blank Screen: If the system is stuck or the screen is blank, charge the gauge or use a conductor to short-circuit the Reset Contacts. A diagram shows the location of these contacts.
6.2 Water Resistance: The gauge is water-resistant but should not be used underwater.
6.3 Pressure Limits: The maximum working pressure is 350 bar; the gauge can display up to 400 bar.
6.4 Loose Carbon Fiber Cover: If the cover is loose, apply a small piece of tape to increase its outer diameter for a snug fit.
6.5 Buffer Screw: There is a buffer screw in the air inlet hole that protects the sensor from high-pressure air shocks. Do not remove this screw. If a POM seal is used during uninstallation, the screw might get stuck in the plastic; re-screwing it is recommended. An image shows the 'Buffer Screw'.
6.6 Contents: The package includes: Gauge x1, Carbon Fiber Cover x1, USB cable x1, Bonded Seal x1, Clean wipe x4, Screen protector x3.