The JANET Project
A tool for fire alarm technicians that provides similar functionality to a terminal program with remote capabilities.The Challenge
While working on fire alarms as a solo service technician there are many times where you would have to check the fire panel and then venture out into the field to remove a device and then walk back to the fire panel to see what status message has popped up. There were also many times where I would be working in the field and the fire panel would be constantly beeping and I didn’t have time to always walk back to the fire panel to hit acknowledge or silence to stop the beeping.
The Solution
The idea was to be able to monitor and receive all of the fire panel output remotely while in the field so I didn’t have to keep walking back and forth. It also allowed me to communicate back to the panel to acknowledge, silence, and reset the fire alarm panel.
JANET has been a great tool that has enhanced my troubleshooting abilities and also allowed me to do inspections of large buildings by myself without needing to have someone at the fire alarm panel monitoring all of the signals. The best part of the project was learning aspects of how the fire alarms work while trying to interface with them.
Order of Operations / How it works
1. Fire Alarm / RS-232
Listen / Receive Signals from the Fire Alarm Panel
When signals are received from the fire alarm panel through the RS-232 adapter they are given top priority and are parsed and processed.
Save the messages to the local log on the Micro-SD card
After being processed the signals are stored locally on the micro-sd card where they will wait to be processed for sending out as an SMS text message via the SIM7000A Module.
Send the messages out via SMS
The messages are processed in order and sent out as an SMS text message.
2. User Commands / In-Bound SMS
Listen / Receive in-bound SMS messages
When SMS messages are received they are filtered by a whitelist and if they are acceptable they are parsed and processed.
Process the Commands
The SMS messages are parsed and if a command is recognized it is processed and the correct action is taken.
Confirmation Message is sent to the user via SMS
After a command is processed, the result of the command is sent back to the user via SMS using the stored phone number.
3. User Commands / In-Bound SMS
Listen / Receive in-bound Contact ID Tones from DTMF Decoder
When new Contact ID Tones are received from the Arduino NANO DTMF Decoder program they are parsed and processed.
Save the messages to the local log on the Micro-SD card
After being processed the contact ID codes are stored locally on the micro-sd card where they will wait to be processed for sending out as an SMS text message via the SIM7000A Module.
Send the Contact ID codes out via SMS
The contact ID code strings are processed in order and sent out as an SMS text message.
JANET Rev 1 Hardware Components
Arduino MEGA2560 Pro Mini
The MEGA2560 Pro Mini is the perfect size for this project. It also offers the correct amount of hardware serial ports and RAM. The extra RAM and storage space are crucial for the size of the project.
Arduino NANO
I am using an Arduino NANO to interface with the DTMF decoder circuit. This process all of the contact ID codes and formats them appropriately before sending them over serial to the MEGA2560.
Ultra Compact RS-232 to TTL Converter
The NulSom Inc. Ultra Compact RS-232 to TTL converter works perfectly for this project. It has a male DB-9 connector and supports 1.8V, 3.3V, 5V logic levels and transfer speeds up to 1Mbps.
MT8870 DTMF Decoder Module
The MT8870 has a stereo 1/8″ headphone jack used to plug in the phone line audio source that you want to monitor. This module works great and does not seem to have much latency.
SIM7000A Cellular Module
The SIM7000A provides LTE Cat M1 connectivity and also has a GPS receiver built in. This device will allow you to send and receive SMS messages and DATA. I use a SIM card from USMobile.
Micro-SD Card Adapter
I am using a HiLetgo Micro SD TF Card Reader. This module is compact and very fast. I am able to get very fast read/write times with a good quality micro-sd card.
TP4056A Single-Cell 18650 Battery Charger Module
I am using one of these battery charging modules to charge three 18650 batteries. The module charges at a 1a rate and my batteries are 3500ah. It takes about 6 hours to charge the batteries fully.
DC-DC Adjustable Boost Module
I am using a DC to DC boost module to boost the battery voltage from 3.7V to 5V and 9V. Each module can provide up to 2a output without getting too hot.
Rev 2 is on the way!
The configuration as listed and pictured above has worked great for the past couple of years but I have been working on a newer version using newer and “better” components. As the new project progresses I will start posting pictures and notes for that one so make sure to check back in the future for updates.