To facilitate the grassroots development of apps, integrations and hardware extensions we’re opening the Garadget’s hardware for personal use. Below instructions will help you create your own Garadget clone and take advantage of its firmware and other software that exists and coming soon.
New to Garadget? Learn about our smart garage door controller, it’s features and how it can improve your daily life.
What you’ll need
Particle Photon x1
- USB charger or other 5V source x1
Relay Module x1
Red Laser diode x1
- 2N2222 NPN transistor x1
- 1K, 10K, 100K Resistors x1 each
- Reflective Tape
- Project Enclosure
Additionally to Photon module at its core, Garadget’s hardware consists of the three elements:
##1. Laser transmitter
Laser transmitter acts as the sending part of the door state sensor. We used inexpensive low power red laser similar to those found in presentation pointers. The circuit contains NPN transistor to drive the laser because Photon’s outputs can not supply the sufficient power for it (Max 25mA @ 3.3V while needed 40mA @ 5.0V). The base of the transistor is connected to Photon’s D2 pin through 1K current limiting resistor.
##2. Laser receiver
Laser receiver circuit uses metal photo-transistor on one side of the voltage divider to detect the amount of reflected light from the laser. When retro-reflective tag is illuminated by the laser, the significant amount of light is bounced back at the device where it can be sensed by the photo-transistor. As result its resistance drops significantly, pulling the middle point of the voltage divider closer to the ground. The Analog-to-Digital converter at Photon’s pin A0 measures that voltage.
##3. Garage opener control circuit
The mechanical relay simulates the push of the garage door opener’s wall button while keeping the two systems electrically isolated. The simplest approach is to use a relay module; it can be driven directly by chip’s output pin. The module’s circuit contains a transistor, current limiting resistor (similar to #1) as well as flyback diode. Additionally we use a 10K pull-down resistor to ensure that during the reset, the relay remains open. The normally open contacts of the relay are connected to the garage door opener’s terminals for wall button.
Power: the circuit is powered by 5V provided by USB adapter. The micro-USB connector needs to be connected to Particle module and 5V also has to be supplied to other parts of the circuit. This can be done by splicing the wires of USB cable so they can be first connected to the board, and then the remaining short part of the cord with micro-USB connector plugged into Photon.
Polarity: Laser’s anode (+) is typically red, photo-transistor’s emitter (-) is one marked with a small tab on the side. The pins on the relay module are silkscreen labeled.
Firmware: the stock firmware for the Garadget is offered to you under GNU General Public License. It can be downloaded from github repository. For Photon programming instructions please visit Particle Website.
Original Garadget: factory manufactured units are available for purchase at very reasonable price. Just as your home-built clone, they welcome firmware tinkering and custom hardware extensions. Your purchase will support the small development team in Colorado and encourage the creation of more open projects like Garadget.
#Permissions and disclaimers
Garadget’s door state sensor technology is subject to pending patent 62/294,886. You’re granted the permission to utilize said technology for your personal use as part of described here build. By taking on this project you understand that we provide no warranty and assume no liability for the process or the results.
Questions? Suggestions? We’re excited to hear from you.