UNO, Blue Man and the Neon Light

RE: UNO, Blue Man and the Neon Light

Jan Cumps — Mon, 09 Dec 2019 22:32:36 GMT

Where did you get the inspiration to use the FET as a Zener diode?

RE: UNO, Blue Man and the Neon Light

jw0752 — Mon, 09 Dec 2019 14:06:05 GMT

Hi Jon,

I love your air wiring constructions. It reminds me of how I used to make my kids practice soldering techniques by having them construct cubes and pyramids out of wire clippings. Another interesting project build!

John

RE: UNO, Blue Man and the Neon Light

ciaburrj — Mon, 09 Dec 2019 00:58:12 GMT

Interesting. You should run the leads through the blue man's hand, and make him look like he's carrying a torch.

Could you drive it with some sort of PWM to keep it "lit"?

RE: UNO, Blue Man and the Neon Light

DAB — Sun, 08 Dec 2019 20:57:07 GMT

Nice project.

DAB

RE: UNO, Blue Man and the Neon Light

jc2048 — Sun, 08 Dec 2019 18:40:05 GMT

Here is how the current through the neon looks.

I've added an additional 12V zener to the MOSFET to lift the voltage it clamps to to about 125V. A 100R resistor on the ground side of the neon bulb lets me look at the current.

[View:/resized-image/__size/600x450/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-41dd6643-fb6b-44f3-9ce5-f286b162027f/contentimage_5F00_205511.jpg:600:450]

Yellow trace is voltage at top of neon (so includes drop across the 100R). Blue trace is current (1V = 10mA)

[View:/resized-image/__size/480x234/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-41dd6643-fb6b-44f3-9ce5-f286b162027f/contentimage_5F00_205512.png:480:234]

Initially, before the trigger point, the coil is charging capacitance (the transistor collector-base capacitance, the 470pF cap, and the zener). It then clamps on the zener, which will take the current. The neon strikes and starts taking current away from the zener. The voltage starts to fall and the neon then glides down on the remainder of the energy in the coil.

RE: UNO, Blue Man and the Neon Light

Jan Cumps — Sun, 08 Dec 2019 15:29:12 GMT

Next time I get a blue man, I'm going to drill 2 holes in its back of the head and put LEDs inside. Then blink them.

A nice flickering effect. Must be able to use that for something.

XMAS time is coming...