Archive for March, 2005

mcmaster-carr for all your rod and knob needs

I was looking for a source for knobs, and remembered McMaster-Carr where I got the aluminium disc for the pit drinkwarmer. Search for “Phenolic Control Knob”. They got everything. Incidentally, they also do ball joint rod ends for my pedals.

the skanky part of the SNUPS

See that case? That’s 0.5mm aluminium sheet with a plastic drinking cup. That’s right. Skanky.
Next: soldering.
{{popup SNUPS_20050330.jpg SNUPS_20050330 800×454}}SNUPS_20050330


Well, here is a design for the PCB for the SNUPS according to the latest schematic. I used the free software from expressPCB but won’t order the board from them because of the nonstandard shape and the fact that I only need one. They do a special deal for 3 identical boards about 3″ x 4″ shipped to Australia next business day for AUD $90. Pretty good if you’re making prototype boards.
It’s not very neat, but it all had to fit onto a PCB that fits inside one of those disposable white plastic drinking cups. It fits… just.
{{popup SNUPS_v2e_PCBv2.gif SNUPS_v2e_PCBv2 1048×848}}SNUPS_v2e_PCBv2

revised SNUPS

This one actually blows up standard LEDs if 220R resistors are used. The LEDs appear to be getting the full 12V now. I’ll breadboard it and see…
{{popup SNUPS_v2e.gif SNUPS_v2e 867×564}}SNUPS_v2e

late night flash

I think I might have figured out why my SNUPS doesn’t work with high-current LEDs.
V[BE] in the LED-switching transistors must be about 0.6 – 0.75V for the transistor to go into full conductance. With the current circuit, the LED needs about 5.5V across it to operate, so V[E] must be abut 5.5V. But this is much higher than the base voltage, so no current flows (V[BE] is reverse biased).
If I move the LEDs to the collector side and tie the emitter to ground, I can maintain appropriate V[BE] throughout the switching operation and supply the LED with the 5.5V it needs from the 12V supply. It just might work…


what happens when you fly a 4-player MP sortie by yourself
oops_20050321 (22k image)

a great couple of sorties

Thanks to Hootsta and Tonka for some insane sorties last night.
Being a FAC is great! “Target is two SA-6 launchers, one either side of my smoke.”
HitMySmoke (26k image)
Hootsta departing the fix
Hootsta01 (23k image)


Work is again underway on the SNUPS. I have the first stage (555 timer stage) breadboarded and working nicely. Next is the decade logic stage, then the output stage and construction. Click {{popup PitStrobe22.gif PitStrobe22 855×496}}here for the schematic as it stands.
PitStrobe22_breadboard (41k image)

my other little project

Another little project was completed yesterday. This one my wife and I have been working on for a bit over nine months:
Newbie_20050313_Asleep (60k image)
I wonder if Fisher Price make a HOTAS?

the tiger pit

Courtesy of GI_Jew. Thanks mate.
tiger_pit01 (29k image)
Many others here.

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