In GATED mode, removing the gate will reset the flip-flop. The AUTO switch in its UP position will pass an inverted gate signal to a second differentiator, C5, R22 and D4. When a gate signal is removed, the positive going edge runs through U4 (pins 1,2,3 & 11,12,13) and D4 to reset the flip-flop. In this mode removing a gate signal will cause the MOTM’s output to fall.

Pressing the RESET switch (R-S on the schematic and PCB) will also cause the flip-flop to reset. D7 protects the output of U4 pin 11 from the damaging 15V when the switch is pressed. When the AUTO switch is down, the OMS-820 is in RESETABLE mode. The gate input and gate switch are no longer able to reset the unit, but the RESET input is. This input socket drives a transistor schmitt trigger similar to the one used on the gate input. The output goes, via the AUTO switch, to the differentiator. A positive signal at the reset input will trigger the differentiator and reset the flip-flop.

Another way to reset the flip-flop is via the AD function. This utilises the actual output of the MOTM-820 to control the discharging process. When the output of the MOTM unit exceeds a certain value, approximately +5V, the flip-flop is reset and the output voltage will drop.

U3 (5,6,7) acts as a voltage follower or buffer. This device ‘sniffs’ the voltage on its input, the MOTM-820’s output, and reproduces it at its own output. The output voltage of the MOTM is therefore perfectly replicated by U3 and this is then used by the OMS-820 without having any effect on the MOTM-820 or its connected modules. The BUFFERED signal is used by three parts of the OMS-820. One of these is for the LFO mode, which we have talked about already.

Also monitoring the BUFFERED voltage is a comparator based around U2. When the voltage exceeds +5V or so, the comparator’s output goes from 0V to +15V. With the AD/R switch in the AD position, ie. closed, the output is passed via D3 into U4 and resets the latch. This tells the flip-flop that the attack phase is over and the decay phase is about to start. Pin 10 therefore goes low and the MOTM-820 is discharged.

R1 and R2 set the +5V threshold level. R10, with R3, provides a thin slice of positive feedback to force the comparator to switch cleanly... its another Schmitt trigger again. There are four LEDs on the OMS-820 all of which are actively driven. U3 (pins 1,2,3) is a current source for the OUT LED. The LED is in the feedback loop and it will have a current that is determined solely by the voltage presented to the end of R6. R6 controls the sensitivity of the circuit. 1K produces about 5 mA through the LED for a 5V output of the MOTM-820.

The other three LEDs are driven in a current chain. The chain is driven from a current sink Q1 and associating circuitry. R7 sets the current to be a maximum of 7mA or so. This means no matter what the LEDs are doing the chain always draws 7mA. This prevents switching noises affecting the power supplies and allows all three LEDs to be driven with only 7mA.

Each LED is turned on and off by PNP transistors. When the transistor is off, the LED has current going through it and is on. When the transistor is on, it ‘shorts out’ the LED and the voltage across it drops and the LED is turned off. There are LEDs for the GATE and RESET inputs, and the SET output of the latch.

The last bit of the circuitry is the two pots. These simply form voltage sources to a couple of resistors. The current flowing through these resistors is added to the control nodes for the UP

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Oakley MOTM-820, OMS-820 manual
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MOTM-820, OMS-820 specifications

The Oakley OMS-820 and MOTM-820 stand out as exemplary models in Oakley's extensive range of performance eyewear, designed for both sports enthusiasts and everyday users. These models capture the essence of Oakley's commitment to innovation, superior optical technology, and stylish design.

One of the main features of the OMS-820 is its advanced lens technology. Utilizing Oakley’s High Definition Optics (HDO), the lenses provide exceptional clarity and optical fidelity. This technology minimizes distortion, ensuring that users have an unobstructed view, whether they are on the golf course, cycling, or participating in other outdoor activities. The lenses also come with Oakley's PRIZM technology, which enhances color contrast and visibility in various environments, allowing users to detect changes in terrain or obstacles more readily.

The MOTM-820, on the other hand, emphasizes adaptability and comfort. It features a lightweight frame crafted from Oakley’s proprietary O Matter material, which provides flexibility and resilience. This ergonomic design conforms to the shape of the wearer's face, ensuring a secure yet comfortable fit during extended use. The adjustable nose pads and temples further enhance comfort, making it ideal for an active lifestyle.

Both models incorporate Oakley’s innovative lens treatment technology, which includes anti-fog and anti-scratch advancements. This ensures that the eyewear remains clear in challenging conditions, whether users are facing misty weather or rugged terrains. Additionally, the UV protection offered by these lenses shields wearers from harmful rays, a critical feature for outdoor activities.

A striking characteristic of the Oakley OMS-820 and MOTM-820 is their customizable aesthetics. Available in a myriad of colors and styles, users can express their individuality while enjoying high-performance eyewear. This attention to style combined with functionality makes these models popular choices among both athletes and casual wearers alike.

In summary, the Oakley OMS-820 and MOTM-820 are distinguished models that integrate cutting-edge technology with comfort and style. Whether for competitive sports or daily wear, these eyewear options exemplify Oakley’s commitment to enhancing visual performance and user satisfaction.
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