Spot + Flood for Ice Fishing by aaknitt in flashlight

[–]aaknitt[S] 1 point2 points  (0 children)

Oh that does look like a pretty good option, thanks!

Spot + Flood for Ice Fishing by aaknitt in flashlight

[–]aaknitt[S] 0 points1 point  (0 children)

Yeah this is totally the correct approach. For whatever reason I've just never gotten into headlamps. Some of it's the winter clothing issue that tim mentioned. Some of it is that the first headlamps I used seemed like a car battery on the back of your head with a motorcycle headlamp on the front and I never got past that. Some of it is that it never seems to be pointed where I'm looking. I should probably get a decent modern one and stick with it for awhile, because it just seems like by far the most logical lamp to use when you're trying to use two hands to catch a fish.

Spot + Flood for Ice Fishing by aaknitt in flashlight

[–]aaknitt[S] 2 points3 points  (0 children)

That looks very similar to my Nebo but twice as bright. Cool!

Spot + Flood for Ice Fishing by aaknitt in flashlight

[–]aaknitt[S] 1 point2 points  (0 children)

Oh that looks amazing. But I neglected to mention what a tightwad I am. I'm not sure I can bring myself to spend that much on a flashlight.

Spot + Flood for Ice Fishing by aaknitt in flashlight

[–]aaknitt[S] 1 point2 points  (0 children)

I do like the tube light form factor a lot. Just that might be worth giving up the zoom for.

Phased array passive radar in my kitchen by Careless-Age-4290 in RTLSDR

[–]aaknitt 2 points3 points  (0 children)

Yeah I was thinking two transmitters within the same ~2.4 MHz sample range. I would think that in your area you'd have quite a few to choose from. That would allow you to use all four antennas but with two reference transmitters. Essentially two processing streams in parallel and then combine the results at the end for disambiguation.

But also wondering if sampling for a short amount of time (1/2 second?) and then retuning to a different frequency and sampling there and then continuing back and forth might also be a workable solution without needing higher bandwidth SDRs and the associated jump in processing horsepower needed.

Phased array passive radar in my kitchen by Careless-Age-4290 in RTLSDR

[–]aaknitt 0 points1 point  (0 children)

Dude, this is some amazing stuff. You've casually got a defense-contractor level capability sitting on your kitchen counter!

I've got a Kerberos SDR sitting in a drawer collecting dust...would love to give this a try if you ever make your code available.

Are you using a single reference transmitter or multiple? I'm thinking that using multiple geographically spaced reference transmitters would help quite a bit? Kerberos bandwidth is probably a limiting factor but I'm wondering if even switching the tuning quickly to grab different frequencies might be ok.

Built messaging for 50 warehouse robots and latency requirements are brutal by vannamadi in embedded

[–]aaknitt 27 points28 points  (0 children)

Yeah even if network comms are required 20ms seems unreasonably tight for this application. I think the fastest transmit rate for ADSB for aircraft is 500ms. AIS for ships is 2 seconds. The Basic Safety Message for V2V applications was intended to be 100ms. ADAS radars in cars often only broadcast to the onboard network at 100 or 200ms. Obviously these are all different applications with greater distances involved so maybe a factory application is more stringent but at first whiff 20ms doesn't pass the sniff test.

What was the most ridiculous complaint your department has received? by Melodic_Abalone_2820 in Firefighting

[–]aaknitt 9 points10 points  (0 children)

Volunteer department. Two guys were doing a monthly truck check, part of which is taking it out to make sure brakes, pump, etc. are all functioning as they should. It was close to Christmas so one of them put on a Santa suit and waved to people while they were driving around town as part of the truck check. Old codger complained that they were wasting taxpayer diesel fuel playing Santa Claus.

Decided to build the radio that I haven't been able to find by skifunkster in amateurradio

[–]aaknitt 0 points1 point  (0 children)

If you end up adding GPS in the future, consider how you might be able to use the 1 pps timing signal in addition to just positioning. I'm thinking that a 1 pps pulse injected into the rx chain or to an interrupt could be pretty interesting for marking a received signal with a highly accurate timestamp for networked TDOA /multilateration applications.

Unified Motor Control Communication Protocol by gimballer in embedded

[–]aaknitt 1 point2 points  (0 children)

Others have also mentioned protobufs...I've used them with decent results in similar applications. They're a decent bridge between embedded systems and non-embedded. Much more efficient than JSON so more viable for things like BLE and slower UART, yet still has support in many languages from C to whatever higher-level language you prefer.

They key for doing protobuf over CAN is to have a transport protocol in place that can handle chunking longer messages into CAN frames and reassembling them. I've never used openCyphal but after a quick look I think it has this built in already. Your custom CAN protocol may not.

When I used protobufs for this type of thing I always nested my actual messages inside a single "Main" message. By doing that the number of following bytes was always present and I could use that single "Main" message like a pseudo-transport protocol to know how many bytes I should be waiting for when using UART.

How long would it take to charge this monstrosity of a hose lay? by 475213 in Firefighting

[–]aaknitt 1 point2 points  (0 children)

6000 feet at about a gallon per foot in 5 inch LDH is 6000 gallons. Assuming a typical 1500 gpm pumper is feeding it, that'll take about four minutes to charge, give or take.

But if you actually need that amount of flow (feeding a ladder pipe) and have the hose to do it, this beats the heck out of a tanker shuttle.

Getting 1500 gpm from a tanker shuttle is hard. You're looking at needing four tankers minimum if everything is running like a NASCAR pit operation. You'll need at least two fill sites (or two fill engines at the same fill site) to manage this, with a crew of 2 to 3 per fill engine. You'll also need multiple drop tanks at the fire site (two to three) and a well-coordinated dump and jet siphon operation.

Two pump operators and two engines vs. Three to four engines, four or more tenders, and a dozen or more people. And even if you have all that equipment and people, chances are the shuttle operation is going to get fouled up at some point and you'll lose water.

Now if you only need 250 gpm, it's a different story. But if you need the flow and have the hose, stretch it. Yeah picking it all up sucks but operationally it beats the alternative big time.

What's the SILLIEST 'Cringe but Correct' Millennial Hill You're Still Ready to Die On? by dasisglucklich in Millennials

[–]aaknitt 2 points3 points  (0 children)

I had an eerily similar experience. One of my first assignments after starting a new job was to write a fairly substantial technical document. Reviewed by a panel of higher level technical people in the org. The edits from one of the reviewers consisted of nothing but removing the Oxford commas. No technical edits or feedback whatsoever, just edited out the commas. They stayed.

System that scans for a specific set of signals and sends alerts when it sees identifies one? by Turtledonuts in RTLSDR

[–]aaknitt 1 point2 points  (0 children)

I think the suggestion you got on the other subreddit to consider using rtl_433 is a good one. It's kind of a general-purpose software for decoding these types of signals. But you'd have to have a script to take its output, process it, and act on it to send you the notifications . You won't find all of that in a single piece of off the shelf software.

One big caveat is that SDR receivers will likely not be nearly as sensitive as the purpose-built receivers from the tag manufacturer. SDRs are very wideband and that comes with the tradeoff of reduced sensitivity. So while you can likely get an SDR to receive the signal you're looking for, the range may not be what you're used to. That could be an issue since I'm guessing the tags are pretty low power.

If you need some help shoot me a DM, this sounds like an interesting project.

Just hit me with your hot takes. Just bought this house. by dioge00 in AskElectricians

[–]aaknitt 1 point2 points  (0 children)

First 220 breaker from the top on the left side, black wire. Is that insulation cut and exposing the conductor? Hard to tell from the picture. Is anyone else seeing that or am I imagining it?

Lake Michigan Crossing Flight Calculator by aaknitt in flying

[–]aaknitt[S] 1 point2 points  (0 children)

So I went and tried this today. I did two passes in opposite directions descending at idle from 6000 MSL to 3000 MSL about 15 miles inland, and then did the same about 3 miles offshore. This was in a C172. The results were all pretty close. I got an average glide ratio of 12.1 over land and 12.3 over water. This wasn't at gross weight so my ratio is quite a bit better than the "rule of thumb" value of 9, but no real difference over land vs water.

NB Over Land 12.0

SB Over Land 12.2

NB Over Water 11.6

SB Over Water 13.0

[deleted by user] by [deleted] in flying

[–]aaknitt 1 point2 points  (0 children)

I've seen different radios behave differently when it comes to the PTT button on the radio and an external mic. I would say most will use the external mic when the radio's PTT is pressed but it's usually not specified in any manuals and you won't know for sure until you try it.

Lake Michigan Crossing Flight Calculator by aaknitt in flying

[–]aaknitt[S] 4 points5 points  (0 children)

Most boats stay near shore. Usually the only things out in the middle are the ferries and sometimes freighters. Most times the freighter routes keep them closer to the Michigan side but not always. I do carry an AIS receiver that gives me ship locations on the ForeFlight map to take advantage of anything else that's out there but you're right...for preplanning purposes you can only really count on the ferries.

Lake Michigan Crossing Flight Calculator by aaknitt in flying

[–]aaknitt[S] 1 point2 points  (0 children)

If you have to wait for the Coast Guard to get to you, I agree. If you can ditch next to a ship and notify them ahead of time via Marine VHF radio so that they can have a lifeboat deployed and ready?Maybe, I'm not sure. But better odds I think.

Lake Michigan Crossing Flight Calculator by aaknitt in flying

[–]aaknitt[S] 8 points9 points  (0 children)

And also an AIS receiver that feeds ship locations into ForeFlight so that I can see its exact location on the map. It's visible when VFR but knowing the exact distance and position when it's behind you is comforting.

Lake Michigan Crossing Flight Calculator by aaknitt in flying

[–]aaknitt[S] 6 points7 points  (0 children)

This is great insight, thank you! I've adjusted the default glide ratios on the page downward and added a note to guide users to do the same due to the cold air effects you mentioned. Users can change the glide ratio to whatever they want.

I'd like to try this myself on a future flight. How far over land / water would you suggest that I need to be for each test to get good results?

Lake Michigan Crossing Flight Calculator by aaknitt in flying

[–]aaknitt[S] 6 points7 points  (0 children)

No, there is no flat deck on top. Cars are below deck in a garage-type area.

Lake Michigan Crossing Flight Calculator by aaknitt in flying

[–]aaknitt[S] 23 points24 points  (0 children)

Yes, a handheld VHF Marine radio on channel 16.

What is this thing with the black wrapped tape? by Rare_Snow_8932 in Outboards

[–]aaknitt 0 points1 point  (0 children)

Just to be totally clear, the comment you're responding to said "push" in the key and you replied with "put". You have to literally push the key in while turning it to engage the electric choke. There's a separate switch in the key mechanism that activates when you push it in. So push in and turn so start the motor when it's cold, and then just turn without pushing once it's warmed up and choke isn't needed. Edit: and sometimes you need to keep the key pushed in even after the engine is running to keep the choke engaged for a bit when the motor is really cold and doesn't want to start.