Reddit reviews First Alert Hardwired Wireless Smoke Alarm with Photoelectric Sensor and Battery Backup, SA521CN-3ST
We found 4 Reddit comments about First Alert Hardwired Wireless Smoke Alarm with Photoelectric Sensor and Battery Backup, SA521CN-3ST. Here are the top ones, ranked by their Reddit score.
Help keep your family safe with this hardwired smoke alarm that wirelessly interconnects with other First Alert–enabled alarms to create a home safety networkEquipped with photoelectric smoke sensor optimized to detect larger smoke particles produced by smoldering fires; helps minimize the number of false alarmsWirelessly connect up to 18 First Alert enabled alarms for the maximum in whole-home protectionHardwired alarm includes 2 AA backup batteries for continued monitoring in the event of a power outageIncludes test/silence button, low-battery warning, EZ access battery doorFirst Alert has been the most trusted brand in home safety since launching the first residential smoke alarm in 1958 (Based on a First Alert Brand Trust Survey in February 2018)
This is the polar opposite of SMD, but I thought I'd share my solution...
While I love DIY, smoke detectors are important. I wanted to interface with my home system but without compromising the integrity of the system.
Get a 120v first alert.
First Alert SA521CN Wireless Interconnected Hardwired Photoelectric Smoke Alarm with Battery Backup https://www.amazon.com/dp/B000EVO9D4
Get the smart relay interconnect.
BRK RM4 Smart Relay for First Alert https://www.amazon.com/dp/B0039PF21U
This includes schematic for wiring to the detector and the color codes for NO/NC relay connection.
~~Get an optocoupler or isolation relay. Mains Voltage! The output of the RM4 is 120V.
Enclosed AC/DC Power Relay with Protection & De-Bounce. Screw Terminals. 120V Trigger Input. https://www.amazon.com/dp/B017743I7S
The RM4 output powers the relay. The screw terminals connect to the 8266.~~
Get a Esp8266; Flash tasmota firmware. Configure for switch and mqtt. Wire it up.
First Alert is now part of the matrix.
Quick update: Did not need the second relay/optocoupler. The BRK RM4 is an isolated relay. Their docs did not make that perfectly clear so I assumed worst case w/o testing it.
I did quite a bit of research looking for the same thing. In the end I decided it was important to keep this safety system separate, using reliable names such as First Alert -- you can interconnect them via. existing home wiring or wireless ... just buy the same brand. I bought these: https://www.amazon.com/dp/B000EVO9D4?ref=ppx_pop_mob_ap_share
But I want the benefits of notifications when smoke alarm trigger (lights turn on, text messages, etc) so I installed this zwave device beside one of them that listens for the sound of an alarm. https://www.amazon.com/dp/B071Z8NM8N?ref=ppx_pop_mob_ap_share
So far, no false alarms, but testing any one of the smoke detectors will reliably trigger this zwave device. Plus, it costs far less than Nest Protect or even Roost, and doesn't rely on a third party cloud.
They have a wired version as well: http://www.amazon.com/First-Alert-SA521CN-Interconnected-Hardwire/dp/B000EVO9D4/ref=pd_sim_60_1?ie=UTF8&dpID=41uKzhkqyXL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=058RS7TT7CC15YB6G704
Yes, I’ve looked at the Insteon smoke bridge. But as you say, the selection of compatible products isn’t great, and the features and compatibility are confusing and poorly documented.
For example, First Alert seems to offer only a single hardwired device with ONELINK, the First Alert SA521CN. But the SA521CN is only a smoke detector, it doesn’t detect CO. I could pair this with a unit which does do smoke+CO like the First Alert SCO501CN-3ST -- but that unit isn’t hardwired so it does me no good.
Then there are First Alert devices which are “interconnected” but lack ONELINK. For example the BRK SC9120B is a hardwired smoke+CO detector which is “interconnected” but lacks ONELINK. Maybe I could buy one of these and pair it with a SA521CA to give ONELINK capability? :(