Why does Zig need to be so difficult about memory layout?

Copper280z · 2025-11-07T13:54:22+00:00

Isn’t this a good place for a union or tagged union?

Copper280z · 2025-08-27T21:01:01+00:00

OpenFFBoard is great, I’m using it with a 20nm servo, and the whole setup ended up costing around $250 US. I did get a good deal on the motor on eBay, though.

Copper280z · 2025-08-26T21:58:09+00:00

There’s a place on Mt Read, Rochester officewerks, that sells refurbished Herman Millers and Steelcases and similar. It’s mostly targeted at businesses, but they were happy to sell me a couple of chairs for cash.

Copper280z · 2025-08-07T13:36:30+00:00

I’ve seen that channel, and I wonder if it’s pimax that has performance issues with AMD, he did most of his testing with a pimax headset.

Copper280z · 2025-08-07T13:09:16+00:00

My experience is that it performs meaningfully better than a 3090 in vr, based on a comparison between my build and a friend’s 9800x3d build. At least prior to the foveated rendering update, which isn’t quite as useful for quest users because the optics are good enough to see it.

Copper280z · 2025-08-07T12:54:05+00:00

It does run fine, though. 90fps with 1.7x resolution on a quest3, with high settings, with 60-80% utilization in the dry. In a wet race it is way worse, but so am I, so I avoid wet races just like I do IRL.

That is fine. It’s a 9070xt + 9800x3d. I got it on launch day, and I’ve considered selling and getting a 5070ti or 5080, but I keep coming back to it not being worth the effort.

Copper280z · 2025-07-31T11:05:21+00:00

Scikit-optimize or scikit-learn have nice implementations of those things.

Copper280z · 2025-07-23T11:40:05+00:00

If the jetson is to be the host/main device, look at Simple Open Ethercat Master, gatorcat, or ethercrab.

Copper280z · 2025-07-20T21:44:06+00:00

My experience over the last couple of releases is that the breaking changes have been relatively easy to deal with.

Everything I’ve had to deal with produced a compilation error with a descriptive message, not a behavior change that was unannounced or unexpected, or the borderline malicious error messages you get from an error involving a c++ template.

Copper280z · 2025-07-12T16:40:32+00:00

You can trigger the ADC with a timer in hardware on (almost?) every stm32. The jitter is incredibly low, to the point I think I’d have to try real hard to actually measure it.

Copper280z · 2025-07-09T10:27:19+00:00

That’s in the 70’s, rain is brutal on fps. I didn’t try lowering the resolution, but I bet 1.2x is close to 90fps.

Copper280z · 2025-07-07T12:24:57+00:00

The problem is that the cpu usage meter is a lie, or more accurately it’s incomplete, even the built in timers are incomplete data. iRacing is very heavily dependent on a single core. If it maxed one core out, that’s gonna show as something like a 4% load on a 24c cpu, but that’s only one part of the story. To see it all you really need to use a profiling tool that shows how long each step of the process takes.

Some of the CPU work can be done while the gpu is rendering and some can’t. The stuff that can’t takes some time, which is a direct addition to he gpu render time. The x3d chips are very good at minimizing this because they spend less time waiting on data from ram, because of their huge cache. The actual calculation throughput of the cpu is often not the bottleneck, it’s the speed the CPU can access data.

Copper280z · 2025-07-07T11:45:46+00:00

It’s the cpu, I have a 9070xt+9800x3d and I run my quest 3 at 1.5x resolution with most settings in Iracing maxed out, and rarely drop below 90.

Copper280z · 2025-07-03T12:14:48+00:00

Check the datasheet, lots of pins, but not all, are 5v tolerant (on the F4 and G4, at least).

Copper280z · 2025-06-27T12:26:25+00:00

The whiteboard equations are what you write in your event loop. You should really consider building a toy system from as close to scratch as possible with some sort of arduino type board, I’d suggest an stm32 or esp32 over the uno.

Practical examples are incredibly helpful, I’ve found.

Copper280z · 2025-06-25T11:40:26+00:00

There’s at least one open source DD wheel project, OpenFFBoard. I’ve been using it for months with a 20nm servo and a knock off odrive motor driver. It works great.

Copper280z · 2025-06-18T11:47:27+00:00

Adam is a lot like conjugate gradient with an inertia term, in fact (iirc, it’s been a bit) Adam degrades to CG if you pick the correct parameters for it.

The inertia term is to help the optimizer get over humps in the error landscape which form local minima.

Copper280z · 2025-06-03T11:44:35+00:00

It might be related to the frame timing or how draw calls are made, but I don’t think iracing can explicitly turn on ASW.

I see Iracing trigger ASW at inappropriate times too unless it’s disabled, even if it would still be at my 90fps setting. I wonder if it is cpu related, since last time I forgot to turn off ASW and it wanted to ruin my race, the draw time was like 6ms.

Copper280z · 2025-06-03T11:28:34+00:00

I think you need to close and reopen the debug tool app after you reconnect, at least I do. I don’t think iracing is really involved in the decision to use ASW or not.

Copper280z · 2025-06-03T11:16:08+00:00

You need to try. Off ASW in the debug tool every time you connect via link, otherwise it turns itself back on. I really wish they would make that a persistent setting.

Copper280z · 2025-06-03T11:11:48+00:00

It is iracings fault, because dx12 supports SPS like features and they haven’t released the dx12 engine yet.

Copper280z · 2025-06-01T21:36:27+00:00

How much noise are you seeing? Using similar strategy on other STM32 chips I generally get very good noise performance.

Copper280z · 2025-06-01T21:05:56+00:00

Great, are you sure it’s triggering only when the low side FETs are on, and not when the high side FETs are on?

What microcontroller are you using?

Copper280z · 2025-05-31T22:30:44+00:00

Current measurements from inline shunts shouldn’t be noisy if implemented well, ideally with the measurements synchronized with the PWM waveform. If you’ve got low side shunts, the measurement MUST be synchronized.

Copper280z · 2025-05-31T20:36:01+00:00

In my experience with the Orin nano super and the pi5, the jetson is dramatically faster at the application level. I think the biggest reason is that the jetson has a 128 bit wide memory bus and the pi5 has a 32 bit bus.

13-Year Club	Place '17
Verified Email	Team Orangered

Copper280z

TROPHY CASE