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