So, measure the time interval and you can get a rough
idea of the ambient light level that is powering the sensor.
This mode of operation is called demo mode (labeled
DM on the sensor enclosure). There is also timer mode
(TM). These modes are selected via a switch on the solar
BLE sensor PCB. Basically, the difference between these
• In demo mode, the solar BLE sensor transmits data at
the previously mentioned light level governed time intervals.
Also, demo mode does not charge the onboard super-capacitor.
• In timer mode, it transmits
data at five minute intervals in
variable light levels. If the super-capacitor is not fully charged, it will
be charged during this mode of
• In timer mode, data is
transmitted for approximately 30
hours — even in total darkness —
after the super-capacitor is fully
The super-capacitor can also be
charged via the 10-pin GPIO
connector on the solar BLE sensor.
Figure 8 shows the sensor PCB
plugged into this connector. The
sensor is plugged into the debug
board and then the board is
connected to a USB charger. In this
configuration, the super-capacitor
will be fully charged in about 10
minutes. Alternatively, you can also
use the USB port on your computer
for charging the super-capacitor.
Of Course, There’s
an App for It
Granted, you don’t want to be
tethered to your PC while receiving
telemetry from your symbiont
sensor-equipped bot. Luckily,
Cypress is a couple of steps ahead
of you and your wandering robot.
There is both an Android and iOS
app for receiving and logging data
from the solar BLE sensor.
Once you’ve downloaded and
installed the requisite app for your
mobile device, just flick the
Bluetooth toggle in your Settings,
Up to 10 solar BLE sensors can be read at the same
time. Likewise, up to 10 sensors can be logged at the same
time. These logs are saved in a CSV format file consisting of
up to a maximum size of 50 MB. This size limit is comprised
of up to five log files, with each file limited to 100,000
entries. The logs are added to the device in a rollover file
system fashion where the oldest file is replaced by the
newest file. Therefore, run tests of your data stream before
40 SERVO 01.2017
Figure 6. The main toggle switch has six silver legs along the right-hand edge on the
Figure 7. The underside of the debug board.
Figure 8. A solar BLE sensor attached to the debug board via the 10-pin GPIO
connector. This configuration will charge the super-capacitor when plugged into a USB