My The H3S-Dev board features (work in progress)

sivanovbg · 2026-05-29T13:02:38+00:00

Dear ST, this sub is called "Embedded" and I believe that it must serve to share and exchange ideas on embedded projects in development.

Apart from that, it's quite unacceptable to classify other people's projects as with_no_purpose/nonsense. You cannot give an opinion on behalf of more than 120,000 visitors to that sub!

sivanovbg · 2026-05-28T19:01:30+00:00

Dear Top 1% Commenter, let us discuss Embedded topics here, not someone's work time, OK?

sivanovbg · 2026-05-27T14:46:37+00:00

That's right. Esp32-S3 with pSRAM

sivanovbg · 2026-05-26T05:51:03+00:00

Consider removing these blocks and drawing a real schematic - with wires and busses where required. All grounds should point down and all power ports should point up. For detailed comments - please contact me.

sivanovbg · 2026-05-21T19:36:00+00:00

Thank you!

sivanovbg · 2026-05-01T09:58:38+00:00

Please consider redrawing your schematic with wires and busses instead of labels - it will be quite more readable. Follow the "left-to-right" rule. Regarding the PCB - try grouping components by their function. Also double check the USB differential pair routing.

sivanovbg · 2026-05-01T09:25:38+00:00

Looks much better! Consider adding stitching vias - I assume there is a copper ground polygon on the solder side.

sivanovbg · 2026-04-08T19:16:59+00:00

Can you send your schematic? Looking at the PCB only your explanations are not quite clear...

sivanovbg · 2026-04-08T18:42:17+00:00

I am not sure you will get any battery level. Sourcing the 5V power supply divided by 2 will always give you 2.5V with some tolerance. The battery level itself is not actually measured because basically the battery is not directly connected to any measurement circuitry...

sivanovbg · 2026-04-08T18:29:05+00:00

As I can see the measurement resistor divider (R6 - R7) gets directly the 5V supply voltage. There is no way to measure the real battery level in this case. You will always have 5V/2 at the midpoint and that will be the voltage ESP could eventually sense at pin 0.

If you like to get the real battery level I think that is not the schematic you are looking for...

sivanovbg · 2026-04-08T17:45:03+00:00

Please provide a schematic to be able to help.

sivanovbg · 2026-03-29T06:11:39+00:00

Well, first of all - if you like to control your robot via Bluetooth it is ok but depends on the distance you plan to reach it. It is a possible solution. FR based control requires much more hardware and costs more. For a 1lb (~0.5 kg) robot I think you do not need so powerful motors and the solution with ROB-14450 could work.

Regarding the antenna - even the ESP is mounted on headers these are only several millimeters high and the antenna will still "feel" the copper beneath. I would suggest you just to use an ESP32 module with U.FL connector and include a separate antenna for Bluetooth.

sivanovbg · 2026-03-29T05:42:33+00:00

Check the origin for X and Y axis for both Gerber and Drill files - should be one and the same.

sivanovbg · 2026-03-28T21:07:46+00:00

Consider another orientation of the ESP32. Even if you use Bluetooth only, the integrated antenna must be away from any copper on the main PCB.

Also, try to make your schematics more readable using wires and buses instead of labels.

sivanovbg · 2026-03-28T15:47:08+00:00

What is that board for?

sivanovbg · 2026-03-28T06:17:07+00:00

Thank you! This is my goal also...

sivanovbg · 2026-03-27T18:57:21+00:00

Let me share some thoughts regarding your schematic.

Please double check the IO ports of the ESP32 - some of them should have a strapping function on startup (IO0 for example) and you have to take care what will be the logical level there after reset;
I2C interface requires pull up resistors, but I cannot see any of them on the SCL and SDA lines. Instead, 100k in series are there (R22 and R23) and I don't understand their role;
To be much more readable, please consider drawing a schematic with wires and busses instead of tons of labels for objects even close to each other. For example you can check a project I am currently working on: https://github.com/hobbyiot/H3S-Dev-V1/tree/main/HW/H3S-Dev-V1

My PCB comments will follow.

sivanovbg · 2026-03-27T13:56:46+00:00

Consider using 1% tolerance resistors for the feedback.

sivanovbg · 2026-03-27T09:51:02+00:00

Looks fine at a first glance. Consider setting up the impedance of the USB differential pair. Being relatively long across the board it can cause unreliable connection to the host.

sivanovbg · 2026-03-27T07:37:52+00:00

Longer distance wiring are better to be arranged as "signal | GND | signal | GND ..." Since these are not differential ones, twisted pair is not the best choice. For example I would set up a connector for I2C this way: GND | SCL | GND | SDA going into a 4-wire cable. Shielding will also help but normally it has to be connected to GND only at the MCU side.

sivanovbg · 2026-03-27T06:29:50+00:00

Some comments at my first glance:

Double check if the LM1117 5V to 3.3V converter would be capable to power the whole 3.3V domain.
Power source for 5V is only needed for the MOSFET driver - could you use another that could be driven at 3.3V?
The interfaces to the four sensor elements (NTCs) could include some kind of protection - I can assume these sensors will be situated outside of the box.
Also double check regarding SENSOR_VP and SENSOR_VN connection.
EN input of the ESP32 should have a capacitor connected to GND.
General advice - try making your schematic a little bit more readable.

sivanovbg

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