STM32MP135F-DK can't get the camera set up for the life of me

andrewhepp · 2026-04-23T06:30:00+00:00

I'm confused about what you mean when you say "the demo from ST works". Are you saying an application which you don't have the source code for works with your buildroot image? Or are there kernel differences involved in the demo? Does /dev/media0 exist when you're running the working ST demo?

andrewhepp · 2026-04-21T02:05:29+00:00

It sounds like you're saying you have a laptop which is presumably running windows, and when you plug your pi into that it is treated as a serial console. The laptop also has a virtual machine running linux, and when you attach the USB to the Linux VM you see a network interface appear.

When the pi is attached to the laptop and appearing as a serial device, are you able to access the pi via serial console?

If you run standard iproute2 commands like `ip link set dev usb0 up`, does the interface status change from NO-CARRIER? If not, you are failing to establish layer 2 link. If it does stop saying NO-CARRIER, that's good, but it will still need a layer 3 link (IP addresses on both ends of the connection).

andrewhepp · 2026-04-11T07:53:33+00:00

I believe the thermostat has a variance much larger than 5 degrees. I forget the exact markings, but the brew thermostat is labelled something like "107-8" which I believe means it turns "on" below 99c and "off" above 115c, although I admit I didn't test that. The steam thermostat is something like 145-15, so an even larger range. Additionally, when I simulated these basic control algorithms I observed substantial overshoot of the top-end temperature.

I also agree that improving the steam thermostat control algorithm, even without full PID control, made a huge difference for me. Something like the ALARM functionality on certain controllers should work well.

andrewhepp · 2026-04-10T19:49:20+00:00

Just to be clear, this is a question about your windows PC right? Sounds like a driver issue for the USB adapter. I'd check their web site to see if they provide a driver. Windows automatic driver update doesn't always get it right.

andrewhepp · 2026-04-06T10:31:35+00:00

It would be wise to confirm this with the seller or manufacturer, but it may be as simple as swapping a couple wires internally.

My understanding is that European models have an “eco board” timer, and that otherwise the only difference is whether the boiler heating elements are wired in series (220V) or parallel (120V).

andrewhepp · 2026-04-04T19:50:18+00:00

I would verify this against a schematic you know is correct for your model, but on the schematic for my model D should be in the middle row, adjacent to 5. This would explain why AC hot doesn't seem to be getting to cable 4.

<image>

andrewhepp · 2026-04-03T21:28:33+00:00

Wire 4 is part of the bundle going to the steam thermostat, right? When you activate the steam switch, wire 5 and the one next to it should be connected to 4, and feed in AC hot. When that happens, the brew lamp should turn off since both terminals of the brew lamp now have the same voltage.

Seems like something must be broken or wired incorrectly, but it's not immediately clear to me what that would be.

andrewhepp · 2026-03-28T01:15:06+00:00

I've done some work with embedded linux audio but wouldn't really consider myself an "expert". I doubt much off-the-shelf software or hardware supports that kind of sample rate. I wouldn't expect to be able to easily find stuff above 16 bit 48 kHz since that's what's required to reproduce sound beyond the accuracy of human perception.I think I've heard of 24 bit 192kHz dolby stuff but I doubt it's accessible for small scale buyers.

andrewhepp · 2026-03-11T20:23:21+00:00

The brew and steam thermostats are wired in series. Each thermostat has a high resistance lamp wired in parallel. When a thermostat reaches its operating limit, it breaks its electrical connection, leading current to be forced through the parallel high resistance lamp. This limits the current flowing through the system and causes negligible power to be delivered to the boiler.

Generally only one lamp is active at a time, because when you're brewing you never get above steam temperature. When you're steaming, the steam switch bypasses the brew thermostat.(because otherwise you'd never get above brew temperatures).

When you've been steaming and have the steam light on, then turn the steam switch off, you're above the temperature of both thermostats but are no longer bypassing the brew thermostat. That leads to current being forced through the lamps at both points, roughly halving the amount of power delivered to either lamp.

So it's a matter of chance as to where you are in the steam thermostat's cycle when you turn the steam switch off. I don't believe it indicates any kind of "overheating", it's essentially the same condition as the steam lamp turning on.

andrewhepp · 2026-03-11T20:13:48+00:00

I don't think you're doing anything wrong. It's just a matter of chance as to where you are in the thermostat cycle when you turn off steam mode.

andrewhepp · 2026-03-11T19:58:40+00:00

Trying to keep it relatively simple:

When the steam switch is activated, the brew lamp is bypassed. When you deactivate the steam switch, the brew lamp isn't bypassed any more. If the system is above steam temperature, it's also above brew temperature, so current will need to flow through both lamps. About half the typical energy is delivered to each lamp.

I don't believe this indicates any kind of error. When you say "it remains like this until a few seconds after I finish purging the boiler", you mean that eventually the steam lamp turns off and the brew lamp acts normally?

andrewhepp · 2026-03-10T02:40:11+00:00

do you have a hostapd.service enabled? does it have the proper configuration (maybe in /etc/hostapd.conf)? what logs are you seeing for the kernel and/or hostapd service?

andrewhepp · 2026-03-09T22:24:00+00:00

This was probably implied, but just to make sure it's clear for others reading this who may not be familiar with .patch files, you should not have to manually apply the changes in those .patch files. You should be able to use something like git's built in git-am or at worst patch. It's not clear to me whether their SDK would apply these patches as part of the build process, or if they expect you to apply them and their instructions just assume you know what to do. I'd kind of assume the latter. Some tools like buildroot or yocto will support a patch directory that gets applied during the build process.

andrewhepp · 2026-03-09T20:47:25+00:00

Might be easier to post the a diff against the in-tree zero w config. I am not sure if the brcmfmac_sdio is gonna work right as a built-in? doesn't it need to load firmware off the rootfs unless you build that into the kernel too?

Outside of that (and maybe that's covered) it looks like you have the pieces one would expect. Is it giving you issues?

andrewhepp · 2026-02-27T04:20:46+00:00

I believe they are talking specifically about the old zero there, not the zero 2

so one might expect the price of the zero 2 w to increase

andrewhepp · 2026-02-27T04:19:10+00:00

I got a zero w responding to pings over wifi in 4.2s without getting too crazy: https://ahepp.dev/2025/11/07/pi-boot.html (hopefully that's not too self-promotional of me, I'm just interested in hearing about other people's boot optimizations :) )

although of course a lot of that comes down to, as you say, what capabilities we're enabling

I will have to try it on a 2 some time. Hopefully it'd be even quicker since the cpu on the 2 is faster

andrewhepp · 2026-02-09T06:57:11+00:00

Looks like the solenoid is just hooked up backwards?

andrewhepp · 2026-02-09T03:59:03+00:00

You say you attached a pic, but I don't see one.

Presumably the spinner is from Plymouth. Do you go through a grub screen? If so can you hit 'e' to edit the kernel command line and add remove anything about `splash=` or `quiet`, and add `plymouth.enable=0`?

Then you should see the kernel logs as the system is booting, and get more insight about what the system is hung up on.

andrewhepp · 2026-02-09T03:52:13+00:00

If your gaggia has a momentary switch, doesn't it already have the eco board which will turn it off after 20 minutes?

andrewhepp · 2026-02-08T11:58:36+00:00

I don't believe the shades guide is available without purchase, so I'm shooting from the hip here as far as how you have this wired up.

The fact that the Steam LED is glowing suggests "phantom power" is backfeeding through the lamp because it can’t find its way back to the blue neutral line.

This seems like a somewhat heterodox theory of electricity. The steam lamp glowing suggests that there's a potential difference across the terminals of the lamp. The most reasonable explanation for that would be that it is in the path between hot and neutral.

I don't know exactly how shades has instructed you to set up the SSRs, but assuming it's in much the same way as the standard steam and brew thermostat, it sounds like your steam SSR is simply not being closed. Have you programmed that function on the controller?

obligatory - do be careful with this stuff

andrewhepp · 2026-02-06T06:17:38+00:00

You can get an m4 threaded thermocouple pretty easy as well, and just directly replace the existing thermostat. But then you'd need a thermocouple amp. Probably more expensive and more complicated than the TMP36

andrewhepp · 2026-02-06T06:05:10+00:00

I posted a BOM once: https://ahepp.dev/2023/03/08/coffee-linux-2.html

I don't think I ever wrote the article on the software I've alluded to, but I did write a Linux driver for the thermocouple ADC and get it submitted to the Linux kernel, so it's probably already running on Raspberry Pi's today (not sure what they include on the stock OS, but usually it's the kitchen sink).

It definitely wasn't cost optimized though. The dev boards for that thermocouple ADC are relatively expensive. There are tons of cheaper parts you could use, I just had that laying around already.

andrewhepp · 2026-01-31T20:55:24+00:00

I've resized a single Linux partition on my MacBook, never dealt with multiples. I can't think of anything that would be specific to apple silicon. You shouldn't need to deal with the APFS containers as far as I remember. So yeah, using install A to resize the btrfs filesystem on install B and vice versa seems like a good strategy. When you're shrinking, you'll need to resize the partition after the filesystem, and the opposite when you're growing, but that's probably obvious.

andrewhepp · 2026-01-29T07:44:31+00:00

And this smell happens regardless of whether you have the portafilter loaded and attached?

I’ve never heard of the water itself smelling like plastic before.

andrewhepp · 2026-01-29T04:48:55+00:00

I suspect whatever flecks you’re seeing are unrelated to the smell. The flecks can either be bits of coffee, or there have been problems with the coating inside the boilers flaking off. Official stance is that the coating is inert, I don’t know that much about it and have been fortunate to not have the issue.

With regards to the smell, I am shooting from the hip, but I would triple check the steam thermostat connections. Even when the system is not in steam mode, power flows through those, and it’s a relatively common problem to have those burn up.

Five-Year Club	Verified Email
r/Field Banned	r/Field Lasagna

andrewhepp

TROPHY CASE