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#61
New Products release / OpenFest 2025 is this weekend ...
Last post by olimex - October 14, 2025, 12:10:37 PMJoin us this Saturday at OpenFest 2025 in Sofia for the traditional soldering workshop https://olimex.wordpress.com/2025/10/14/openfest-2025-is-this-weekend-in-sofia-come-and-join-us-in-saturday-at-the-traditional-soldering-workhop/ #openfest #soldering #workshop #oshw #foss
#62
NXP / RTC for iMX8MP-SOM-EVB-IND
Last post by ilario - October 13, 2025, 11:37:25 AMOn A64-OLinuXino there was an exposed contact for adding an external battery powering the Real Time Clock present on the board, as explained here, and it was very useful.
Is there something like this for the iMX8MP-SOM-EVB-IND?
Maybe using a UEXT module like the MOD-RTC2? But then, how should one use it? Should one write a Systemd unit probing the RTC and updating the system time? Is there something like that ready to use?
Is there something like this for the iMX8MP-SOM-EVB-IND?
Maybe using a UEXT module like the MOD-RTC2? But then, how should one use it? Should one write a Systemd unit probing the RTC and updating the system time? Is there something like that ready to use?
#63
ESP32 / ESP32-H2-DevKit-Lipo - Battery...
Last post by lmerckx - October 12, 2025, 07:27:57 PMHello,
I have the Olimex ESP32-H2-DevKit-Lipo and a battery 3.7V 1400mAh (JA-803450P) and try to measure the voltage of the battery to compute the percentage of the battery but I receive strange results.
I soldered jumpers BAT_SENSE_E and PWR_SENSE_E1 as explained in the manual and tried the example code to read pins 25 (POWER_SENSE) and 2 (BATTERY).
It works perfectly for the POWER_SENSE: testing with USB connection or battery only, it returns me the expected result.
But I have issues when trying to read the battery voltage.
- when connecting USB only: I always receive the analog value 652 or 653 (so 3716.40 mV or 3722,10 mV after multiplying by 5.7).
- when connecting both USB and battery: most of the time, I receive the same value but once on 10 measures I receive another value: 667 or 668 (so 3801.90 mV or 3807.60 mV). -> I suppose this to be the real measure of the battery because the value slightly increase with time.
- when connecting with battery only: again, I think I receive only the value 652 or 653. To be honest, I'm still not sure of that because I don't have the serial connection to debug and must rely only on my Zigbee report.
Is it the normal behavior of the pin ? I check my solder twice with multimeter and it seems quite good.
Any idea ?
Thanks in advance.
I have the Olimex ESP32-H2-DevKit-Lipo and a battery 3.7V 1400mAh (JA-803450P) and try to measure the voltage of the battery to compute the percentage of the battery but I receive strange results.
I soldered jumpers BAT_SENSE_E and PWR_SENSE_E1 as explained in the manual and tried the example code to read pins 25 (POWER_SENSE) and 2 (BATTERY).
It works perfectly for the POWER_SENSE: testing with USB connection or battery only, it returns me the expected result.
But I have issues when trying to read the battery voltage.
- when connecting USB only: I always receive the analog value 652 or 653 (so 3716.40 mV or 3722,10 mV after multiplying by 5.7).
- when connecting both USB and battery: most of the time, I receive the same value but once on 10 measures I receive another value: 667 or 668 (so 3801.90 mV or 3807.60 mV). -> I suppose this to be the real measure of the battery because the value slightly increase with time.
- when connecting with battery only: again, I think I receive only the value 652 or 653. To be honest, I'm still not sure of that because I don't have the serial connection to debug and must rely only on my Zigbee report.
Is it the normal behavior of the pin ? I check my solder twice with multimeter and it seems quite good.
Any idea ?
Thanks in advance.
#64
UEXT / Re: MOD-GPS & TIMEPULSE pin
Last post by LubOlimex - October 10, 2025, 01:50:58 PMSadly I can't help. We receive MOD-GPS body already assembled.
No idea if you can open the box without breaking it. No idea if it is screwed or glued.
No idea if the pin is led out and available.
No idea if you can open the box without breaking it. No idea if it is screwed or glued.
No idea if the pin is led out and available.
#65
UEXT / MOD-GPS & TIMEPULSE pin
Last post by stoyan - October 10, 2025, 11:45:31 AMHi there,
I want to use the receiver as time source. In this regard I have a couple of questions:
Greets!
I want to use the receiver as time source. In this regard I have a couple of questions:
- can the plastic box be opened without breaking it (screws vs. glue)?
- is TIMEPULSE1 (PIO 11, 1PPS) pin broken out so I can use that for my purpose?
Greets!
#66
ESP32 / Re: ESPHome issue with UART
Last post by ju - October 09, 2025, 01:50:40 PMI tried with esp32dev as well, but same results :-/
I'll try the ESPHome community forums, but I don't expect much...
I'll try the ESPHome community forums, but I don't expect much...
#67
ESP32 / Re: ESPHome issue with UART
Last post by LubOlimex - October 09, 2025, 01:38:23 PMMaybe the configuration or template for ESP32-GATEWAY is wrong. Maybe some other obscure bug. Can't say anything specifically. My advice is to contact the ESPHome community and team. Post in the forums, write an e-mail, point to this thread.
Maybe try some other template, some generic ESP32 template.
Maybe try some other template, some generic ESP32 template.
#68
ESP32 / Re: ESPHome issue with UART
Last post by ju - October 09, 2025, 12:18:10 PMYep, that works better 
It takes a few seconds to get the echo output however (I'd say 5 or 6 seconds).
Is that normal?
And that leaves us with the ESPHome problem, any idea why the same code works fine on a ESP32-POE, and not with ESP32-Gateway?
It takes a few seconds to get the echo output however (I'd say 5 or 6 seconds).
Is that normal?
And that leaves us with the ESPHome problem, any idea why the same code works fine on a ESP32-POE, and not with ESP32-Gateway?
#69
ESP32 / Re: ESPHome issue with UART
Last post by LubOlimex - October 09, 2025, 10:42:09 AMYes, just change:
And it will work fine, connect pin #11 and #13 together (to establish simple echo test) then open serial terminal from Tools -> Serial Monitor and you can send something and you will receive it back after some delay (can be reduced by reducing delay(2000); in the code).
For example, I sent 1234 and this is what I got before during and after transmition:
Edit: If you don't have a wire between #11 and #13 (aka GPIO16 and GPIO32) you won't receive neither Echo nor "Hello..." message!
Code Select
#define RX2_PIN 32 // Receive pin for Serial2
#define TX2_PIN 16 // Transmit pin for Serial2And it will work fine, connect pin #11 and #13 together (to establish simple echo test) then open serial terminal from Tools -> Serial Monitor and you can send something and you will receive it back after some delay (can be reduced by reducing delay(2000); in the code).
For example, I sent 1234 and this is what I got before during and after transmition:
Code Select
Received on Serial2: Hello from ESP32-Gateway Serial2!
Received on Serial2: Echo from USB: 1234
Received on Serial2: Hello from ESP32-Gateway Serial2!
Edit: If you don't have a wire between #11 and #13 (aka GPIO16 and GPIO32) you won't receive neither Echo nor "Hello..." message!
#70
ESP32 / Re: ESPHome issue with UART
Last post by LubOlimex - October 09, 2025, 10:36:32 AMHaha, mystery solved, so this is expected outcome! I made a mistake in the code sorry about that. We wrote above about pin #11 and #13 and in the code I defined GPIO11 and GPIO13 which was the mistake. It should be GPIO16 and GPIO32, my bad I mixed the consequent number of the header and the GPIO number.
I will update the code, test and give you updated code soon.
I will update the code, test and give you updated code soon.