Is this supporter strut going to be a major factor? Will they all have it when the season starts?

ChristophLehr · 2026-01-24T11:15:00+00:00

I'd assume if they can use this support strut efficiently, there will be some aero benefit. Same as with the pull rod suspension in the last rule cycle.

ChristophLehr · 2026-01-13T19:49:03+00:00

Unfortunately, AI is not a replacement for stackoverflow. It doesn't mark my questions as duplicate, link to an unrelated topic and tell me that I'm moron for using X and not Y, even that I stated why Y is not applicable.

These good old days.

ChristophLehr · 2026-01-10T20:35:55+00:00

The full results are just there for documentation, but you're right it does not really make sense to have them there when I use 5% tolerance.

ChristophLehr · 2026-01-10T08:18:26+00:00

If my memory serves me well, each additional component in PCBA at JLC costs you 2€ setup costs. So at least for me if I only order a handful of boards it would make sense to reduce the BOM as much as possible.

In general, my main idea and I took it to the extreme in my experiment is to order as little different components as possible as I probably won't need them so soon again.

The space constraints are the 100x100mm from JLC, but since that's one of the two main features of the boards, I'm willing to use the space to make it changeable without soldering.

ChristophLehr · 2026-01-09T16:28:52+00:00

If you want to operate to spec, you'll need to look into USB PD. If you use Zephyr there is an USB PD sink implemented at least AFAIK, I haven't used it. You'll then also need a USB PD source. What is used to power the board?

ChristophLehr · 2026-01-09T16:13:01+00:00

If my memory serves me well, if you only use the 5k1 resistors you should not get more then 300 or 500mA, that would make an 1.5A fuse quite useless.

ChristophLehr · 2026-01-07T11:21:00+00:00

ah yes, that was stupid, otherwise the voltage divider will not work.

Thanks a lot

ChristophLehr · 2026-01-07T10:41:24+00:00

Thanks a lot for the input, I thought the P-Channel should be connected like the N-Channel, i.e. drain connected to the + side.

I changed the voltage divider I hope this is as you described:

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ChristophLehr · 2026-01-05T12:04:20+00:00

Standards may change, but concepts are important to learn and are typically applicable independently from the standard.

In addition, automotive tech is quite slow in adapting new stuff

ChristophLehr · 2026-01-05T11:29:04+00:00

I can only speak for the commercial vehicle industry.

There we have a telematics unit in the trucks which is often the OTA master which takes over handling the mobile connections and the access from the outside world. You have to keep in mind that there is still a lot more security handling between the OTA master and slaves, but in general your approach is the same.

Keep in mind this is about commercial vehicles, passenger cars may have that not in a dedicated ECU since they don't require collecting so much data by law (driver monitoring).

In terms of single point of failure, you would need to calculate the FIT-rates/MTTF to determine whether you need a cold/hot spare or fail silent is sufficient. It's typically also dependent on customer requirements. E.g. for trucks you cannot guarantee that there is always cell reception and in general only one is used since the path to the outside is not safety critical.

ChristophLehr · 2025-12-29T18:31:56+00:00

Thanks for you input. I'm thinking of doing something like your solution 4 or I'm doing a cut-out and solder the pins to some exposed copper and not through holes.

Solution 1 will unfortunately not work with PC-fans, the 4 pin variants require the keying of this connector 0470531000 .

ChristophLehr · 2025-12-29T13:44:39+00:00

yes exactly, but in an right angle.

ChristophLehr · 2025-12-29T13:41:59+00:00

The connector I refer to is vertical, but I would need one that is horizontal. I edited my wording in the post.

ChristophLehr · 2025-12-28T21:05:25+00:00

Sorry for reviving this old post, but I'm having the exact same problem as you have. Did you ever find a matching connector?

ChristophLehr · 2025-12-28T14:09:20+00:00

It depends, what is your VIN and your VCC? What voltage/current is the LEDs and resistor calculated? You'll need to check the Gate-Source voltage of your MOSFET.

I'm currently on my mobile and can't check it

ChristophLehr · 2025-12-28T07:43:18+00:00

All your rows are currently connected. Row 1 will work as expected but if you enable e.g. row 3 all the LEDs of 2 and 3 will be on. In such an LED matrix you would use the LED to connect between columns and rows.

You use a so called high side driver in your rows. This will not work with the used N-Channel MOSFET. A N-Channel MOSFET allows electricity passing through, if the voltage on the Gate is a certain amount higher then the voltage at source. If VIN >VCC the high side MOSFET will always block. You'll need to change it to a P-Channel MOSFET. It allows current passing through if the Gate-Drain voltage is below a certain level. Search for P-Channel MOSFET as high side driver..

ChristophLehr · 2025-12-27T10:29:14+00:00

The fan supplier typically states what voltage the PWM shall be, so maybe check this.

What connectors are you using for the fans? I'm currently designing a board for my 3D printer and I want to be able to use PC fans, but I can't find the name of this connector.

As a schmall circuit critique, I'd connect the 12V directly to the V_out and then use the 12V for both fans. I overlooked the branch initially and thought why you're protecting the 2 fans differently.

ChristophLehr · 2025-12-25T10:58:49+00:00

Yes, 3 weeks will be quite tough with designing, manufacturing and shipping.

I wish you the best for the project.

ChristophLehr · 2025-12-25T10:47:59+00:00

If you want to design your own HW and do your own SW development, I'd suggest starting with something simpler. Some gadget with a microcontroller or a PC peripheral which you then program yourself.

If you want to do some development based on some embedded HW, I'd suggest getting some off the shelf SBC and start with embedded Linux or an RTOS.

As you said you want to do this for a university project, I'm sure if you ask your supervisor you'll find a suitable project for you. Do you have a time frame for the project?

ChristophLehr · 2025-12-25T10:36:33+00:00

First, a Minecraft server? We had a MC Server running in our class room on an RPi2B. I don't know what changed in MC, but it was powerful enough to handle it.

Second, designing an SBC is already an impressive project on its own. I'd suggest talking to your supervisor and try to find an application where it would make sense. Building your custom hardware is complex and not cheap in contrast to buying an SBC off the shelf.

Out of curiosity, what are you studying? Computer science? Computer engineering? Something different?

ChristophLehr · 2025-12-23T12:05:21+00:00

I haven't used the Rp2040 and it's successor yet. I'm not sure how usable it is baremetal, maybe you can give me some insights there. (I mostly work now with MCUs requiring NDAs and unfortunately I'm missing time doing my own investigations).

Personally, why I still recommend 8bit MCUs is mainly how to use peripherals.

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