This design is posted as an alternative to others being used. To the best of my knowledge, it's a drop-in functional replacement. It's based on the use of analog comparators to establish thresholds for the conversion of garage-door-opener logic levels being presented to an ESP module. As of this writing, two prototypes have been built and are working with ratgdo firmware (V2.57). The schematic for this version includes minor changes from an earlier design to accommodate an 889LM wall panel. Specifications are listed in the table below.
Here's a link explaining what an analog comparator does. The device is a natural fit for the ratgo interface.
Here's a picture of the prototype configuration stacked above an ESP module:
Below is the schematic diagram with some implementation notes. As presented, it only considers the interface with the garage-door opener. Additional features such as LED drivers, or connectors, can be added at the discretion of the builder. A stacked configuration with the ESP module is recommended to exploit the availability of the 5-volt source for powering LEDs.
Parts have been carefully selected for cost and performance. In particular, the analog comparator was selected for internal features addressing unpowered and power-up behavior, along with features ensuring input requirements are met.
Here are the two links included in the schematic notes:
This table captures details of the as-designed interface. It lists input signal attributes, derived requirements (with some desirements), and worst-case analysis results.
Full disclosure:
I have performed a limited amount of testing of power-loss/power-restore cycles on a Security+ 1.0 system having an integrated backup battery. When power was restored, ratgdo recovered operation without anomalous behavior when the GDO had the battery connected. However, when the battery was disconnected, one of 20 cycles resulted in an uncommanded door opening after power was restored. I have yet to investigate what could've caused the anomaly, but it's worth noting this or most any other interface would've been operational well before the ESP module, GDO, or wall panel became operational.
This design is posted as an alternative to others being used. To the best of my knowledge, it's a drop-in functional replacement. It's based on the use of analog comparators to establish thresholds for the conversion of garage-door-opener logic levels being presented to an ESP module. As of this writing, two prototypes have been built and are working with ratgdo firmware (V2.57). The schematic for this version includes minor changes from an earlier design to accommodate an 889LM wall panel. Specifications are listed in the table below.
Here's a link explaining what an analog comparator does. The device is a natural fit for the ratgo interface.
https://en.wikipedia.org/wiki/Comparator
Here's a picture of the prototype configuration stacked above an ESP module:
Below is the schematic diagram with some implementation notes. As presented, it only considers the interface with the garage-door opener. Additional features such as LED drivers, or connectors, can be added at the discretion of the builder. A stacked configuration with the ESP module is recommended to exploit the availability of the 5-volt source for powering LEDs.
Parts have been carefully selected for cost and performance. In particular, the analog comparator was selected for internal features addressing unpowered and power-up behavior, along with features ensuring input requirements are met.
Here are the two links included in the schematic notes:
https://assets.nexperia.com/documents/data-sheet/2N7002H.pdf
https://www.ti.com/lit/ds/symlink/tlv9021-q1.pdf?
This table captures details of the as-designed interface. It lists input signal attributes, derived requirements (with some desirements), and worst-case analysis results.
Full disclosure:
I have performed a limited amount of testing of power-loss/power-restore cycles on a Security+ 1.0 system having an integrated backup battery. When power was restored, ratgdo recovered operation without anomalous behavior when the GDO had the battery connected. However, when the battery was disconnected, one of 20 cycles resulted in an uncommanded door opening after power was restored. I have yet to investigate what could've caused the anomaly, but it's worth noting this or most any other interface would've been operational well before the ESP module, GDO, or wall panel became operational.