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pc-switch: Updates and I need your help

pc-switch update: I know which ESP32-C3 module to use and ramble about which antenna to use. And another reminder to take the survey.

Andrej Friesen

Feb 25, 2024 — 4 min read

I am preparing a pitch for the pc-switch. I already got some feedback on my first iteration of the slides. I am an engineering person and it is hard for me to go on the marketing side of things. So create a story about this device. What problem does it solve for Jeff who has a server in his basement, etc. But hey you never stop learning!

It would be great if you would participate in my questionnaire. To be able to do this I need to have some traction and every bit of participation helps a lot!

Current Progress

The current state of the components is this:

Block diagram showing the components for the pc-switch

Red and black are internal components the user is not directly interfacing with. Orange and green are user interfacing, screen is not on the board though. Why? I do not remember anymore 😅

The brain

I think I am sure about the ESP32-C3. Compared the cost of all the ESP-C3 modules with the ESP32-S3.

ESP32-C3: 1,77 to 1,81 Euros per unit. Price does not go down according to Mouser when ordering 1000
ESP32-S3: 2,70 to 3,60 Euros per unit

I am not sure yet which module to pick.

The official website from espressif lists 10 different modules for that ESP32-C3. Two of them have an external antenna connector. I would love a module with an external antenna AND a PCB antenna that I could just switch in software or a dip switch but could not find something like this. Only using the PCB antenna in a PC case can work but will often fail due to bad WiFi environments. And this is often mentioned in reviews on other products like the ones from SilverStone.

ESP32-C3-WROOM-02U (left) and ESP32-C3-MINI-1U (right)

Designing a custom module with just the ESP32-C3 SoC with some help would be possible. But then there comes a big cost regarding WiFi certification for thousands of dollars. I do not think this kind of niche product by someone new to the game justifies this kind of investment yet. Maybe someday.

So I can go with one of these:

The difference seems to be that the ESP32-C3-MINI-1U has integrated 4MB flash and the ESP32-C3-WROOM-02U does need external flash but can use either 4MB or 8MB.

Since the 8MB version is not available anyway there I can just go with the integrated one. Then I save the flash chip. Is 4MB enough for ESPHome and my use case? I am not sure.

Antenna

Since the internal PCB antenna will most likely not work properly I want to use an external antenna. Some Chinese boards have antennas for the PCIE slots.

But I do not want to block one of these ports. You might want to use them for your bug chunky 3-4 foot graphics card and a network card, etc. If I am going for a PCIE slot I think I build one with a ethernet instead of WiFi. That way we can use the slot properly.

Therefore I am searching what could be a good alternative and bought one of these to test:

Laptop-like antennas (left) and antennas with SMA

If you have any better ideas for an external antenna let me know. I am just playing around with that right now. I would like to have one of these laptop like antennas with a long cable. That way you could attach the antenna to the outside of your cause with velcro and fiddle in the cable to the pc-switch.
I do not know yet how long the IPEX connector cable is allowed to be. If the antenna can not be too long then I may need to include a USB2.0 extension cable which adds to the cost as well. 🤔 So, there is more than enough work 🧑‍🔧

If you have better ideas let me know!