William Dzus Artifacts

Here are my William Dzus artifacts. I admire him greatly. He was a hard-working, kind, and generous man. He came to the United States with little more than ambition and a name of someone to vouch for him and provide him work. He persevered though many setbacks and hardships before gaining recognition though his patent for the Dzus Fastener. He made an important contribution to the WWII defense production, provided his community with jobs, worked to preserve Ukrainian culture, and saved many from the horrors of communism.

He was also my great-grandfather. Thank you, William.

New Compact Prototype

Latest compact board is back from OshPark (www.oshpark.com) and testing is complete. Using the base Adafruit transimpedence amp design we were able to come up with a simple formula for convert the raw ADC values into a UVI. We’re debating whether or not it’s worth it to come up with a resistor divider which gives a bit more signal, but basically doubling the ADC readout and then dividing by 100 does give us plenty of headroom in case someone encounters some really crazy UV exposure. Additionally, we added a slow on-off warning blink should the ADC return a maxed-out value.

 

New UV Sensor Testing

The Roitner Technik GUVA-S12D is too expensive for a product hoping to cost less than $10 each. So I am looking for more cost effective alternative.

Here’s the test rig, consisting of a GUVA-S12D, a VEML6070, and an unspecified LED acting as a light sensor. The ADC reading seems to track the UVI produced by the GUVA-S12D quite well up to UVI 5. From there up to 6.5 (the highest I have measured outdoors) it is a bit lower.

My LED under test shows good visible light blindness. It responds quite strongly to a 365nm UV LED (as does the VEML6050). This might be due to the spectral distribition of the LED. I’ll be looking around for a local lab to quanitfy the response of all three under controlled conditions.

Previous UV Monitor Size Comparison

Here’s the older UV Monitor v 1.2. This one used the same GUVA-S12SD UV sensor, but used it to calculate an accumulated UV dose and warn the user when they are about to get to a dose causing sunburn. Primary issue here was inability to control orientation and therefore the indicdent UV level. Pretty much the only way to use it and get accurate results was to attach it to the brim or top of a hat.