This is only a preview of the November 2020 issue of Silicon Chip. You can view 0 of the 112 pages in the full issue. For full access, purchase the issue for $10.00 or subscribe for access to the latest issues. Items relevant to "Eight Small LED Christmas Ornaments":
Items relevant to "Two Large LED Christmas Stars":
Items relevant to "Balanced Input Attenuator for the USB SuperCodec":
Items relevant to "Automatic hand sanitiser dispenser":
Items relevant to "Wellbeing monitor":
Items relevant to "Boat Computer modified for 4WDs":
Items relevant to "More modified Boat Computer software":
Articles in this series:
Items relevant to "Flexible Digital Lighting Controller, part 2":
Purchase a printed copy of this issue for $10.00. |
Wellbeing monitor
I needed a device that could monitor the welfare of a senior family member living alone to supplement regular
phone calls.
The circuit I came up with reports
hourly movement activity. A smartphone notification message is sent if
movement is below a threshold for defined active hours. Movement events
are recorded hourly to an SD card and
can be reviewed to establish normal activity patterns, and thus identify any
significant changes.
It comprises a passive infrared sensor
(Jaycar Cat XC4444), an ESP8266 WiFi
module (Jaycar XC3802 or WeMos D1
mini), a micro SD card shield (Jaycar
XC3852) and a few other components.
The wiring is elementary, as the SD
shield plugs into the ESP8266 module.
The unit connects to an available
WiFi network and uses the Blynk IoT
application that will work on most
smart devices wherever an internet
connection is available.
When the PIR senses movement, its
output pulls digital input pin D1 of the
ESP8266 high. The number of these
events are counted each hour, and if
the number is less than a preset value
between certain hours, a notification is
sent to a family member. Thus alerted,
the family can contact the senior by
phone, or visit, or inform a neighbour.
The total movement events per hour
are also logged to an SD card file that
can be reviewed online and graphed
for the current or any previous day.
The LED flashes briefly when movement is detected, and when the PIR resets after the timeout delay. The PIR
timeout pot should be set to about 10
62
Silicon Chip
several keywords such as “H” to show
the help, “S” for settings, “L” for the
hourly event log, “ST” for statistics of
the previous 35 days and more. Notifications can be temporarily turned off
for a number of hours using preset buttons, or for longer times in the modify
settings option. There is also an hourly
blackout option to cease notifications
for individual hours.
Configuration
seconds, and the sensitivity pot to
about midrange. While the PIR module operates from 5V it outputs at 3.3V,
for compatibility with the I/O pins of
the ESP8266.
The remote device runs the Blynk
IoT platform with a basic software
interface comprising the main Terminal screen with RTC and Notification
Widgets, two Value Displays, two Tabs
and five Buttons to disable and re-enable notifications. The second screen
has a chart that plots total and daily
movement events against time.
If the available internet service has
limited monthly data allowance, then
a limited data option can be set. This
activates the WiFi only for a 90 second
period if an alarm message is required,
and also once a day when a status message is sent that confirms the system
is functional, allowing the user to remotely interrogate the hourly movement events for the day.
The terminal screen understands
Australia’s electronics magazine
A web page-based configuration is
provided on first power up after loading the software sketch. It permits selection of an existing WiFi network,
the network password, the Blynk Authorisation Token and the text for two
notification messages (the monitored
person’s name and a ‘not OK’ message.)
This means that the WiFi and Blynk
connection parameters do not have to
be hardcoded into the sketch.
The settings are then saved to
EEPROM and are loaded on bootup.
Other settings are changed using the
modify settings option in the terminal
screen. See the user manual for more
details of installing, setting up and using the Wellbeing Monitor (available
for download from siliconchip.com.
au/Shop/6/5680).
A QR Code download is also provided to quickly recreate a copy of the
Blynk Project.
If you have Blynk already on your
smart device, open the app, log in, create a new project then tap on the QR
Code icon next to the info icon at the
top right of the project page. Then scan
the QR Code for this project using the
device camera.
Phillip Webb,
Hope Valley, SA. ($100)
siliconchip.com.au
|