Transcript Special Sensor

The Extinguisher
Special Sensor Presentation
Hamamatsu UVTron Flame Detector
By: John Miller III
Drs. Arroyo & Schwartz
The Sensor
● Looks like a light bulb
● Operates at 350VDC
● Operates in the
spectral range of 185
to 160nm
● Has two leads, anode
and cathode
● Surges current when
it detects flames
The Driver Board
● A good engineer is a
lazy one, so I bought
the driver board!
● Requires 5VDC input
● It has three different
outputs
● I am using the open
collector output,
mainly so that I can
test with an LED
The Test Circuit
● Consists of a 3A
5VDC regulator, a low
ESR 10uF capacitor,
a 1uF cap, a 10k
resistor, an LED, the
UVTron sensor, the
driver board, a lithium
ion battery, my
Atmega128 PCB, and
a breadboard
Some Problems….
● Needed to increase pulse width of driver board
output so that I could detect with Atmel (and
visually on LED) with a polling routine. I could
just as easy use an EIRQ to detect, but I could
still not see a 10ms blink on LED
● Output originally 10ms, with 1uF cap I increased
it to ~1second.
● Needed VERY stable 5V, so I added low ESR
cap to input of regulator to increase noise
performance
● Sensor works too good, which leads me to my
next slide…………………..
The Cone filter
● I want to see a flame directly in front of the sensor so that my tank will know where the
flame is exactly
● With paper (I will use more sophisticated materials on final design) I created a cone to
place over sensor
● With cone I still had incorrect readings (due to reflection of waves)
● I determined that it will need a very small opening, and that it must be very circular in
form to not have wave reflection (I looked this up online on physics sites)
● It works!!!!! Detects only when within ~5 degrees of opening
● I have a temperature sensor to work in conjunction with this to detect location more
exactly