VFO Encoder selection for Xiegu G90

From time to time someone start searching for part number of the VFO encoder.

Here is a selection of part numbers for encoders without detent (no clicks) and with detents (like the original one).

A NOTE FROM  PA2HJK, received by e-mail:

Hello Adrian, 

Thank you for all the information about the Xiegu G90.  I used it to replace my VFO encoder but I had to reverse the outer connections  ( of the 3 pins side) of the encoder. The switch worked fine but the rotation was inversed. I have tried several encoders from Bourns and ALPS but they where all reversed.

Maybe you can add this information to your website to help other Hams.
 

73’s  Harm Jan  PA2HJK

 

An email exchange with Paul VE7NRI showed the same problem. 

A note based on IV3TEK Luca emails and practical experience:

 

On the left is the broken original encoder while in the right side is the Bourns replacement PEC11R-4120K-S0018.

While PEC11R-4120K-S0018 have knurled shaft, it is slightly longer than the original Chinese encoder as seend in the picture above.

 

Luca made a PVC disk to compensate for that:

If keeping the original knob is not mandatory, a flatted shaft will have the same lenght.

Thank you Luca for the detailed feedback! 

 
 

 A NOTE FROM ME:

When I searched for the proper replacement I assumed that Xiegu G90 use standard phase in it's rotary encoders and focused on dimensions and mechanichal criterias; never imagined that they are not delivering the same way. 

Therefore, it is necessary to cross the terminals (small pieces of wire) for the below encoders in order for it to function properly.

 Taken the above into account, you must cross the pins to match the rotation of the new encoder with the result of the VFO or to search for the cheap Chinese-made replacements.

To match the desire of the user, ICOM use a lever to "add" detents to some of their radios. When using in mobile, detents may be convenient while using it stationary, no detents might be the choice.

There are a lot of manufacturers that make cheap PC11 type encoder but the reliability is not very good; while they can be used in home-made projects, in the radio a more sturdy one is needed. 

Also, they might fail and most hams try to find a faster way to repair the radio than to send it back to China and wait a few months.

Therefore, here are a few options for those "brave hams" that will take the things into their hands and will repair the radio by themselves.

As a personal observation, with more than 18 pulses per revolution it is a pain to use a no detents encoder...

From BOURNS:

No detens:

PEC11R-4020K-S0018 with knurled shaft, 20mm lenght, no detents, momentary switch and 18 pulses per revolution.

PEC11R-4025F-S0018 with flatted shaft. From ALPS, EC11E, 20mm long flatted shaft (only) momentary switch.

With  detents:

PEC11R-4120K-S0018 - 20mm long shaft, knurled (4120F for flatted shaft), momentary switch.

PEC11R-4125K-S0018 - 25mm long shaft, knurled (4125F for flatted shaft), momentary switch.

 

From ALPS: 

No detents:

EC11E153440D with 15 pulses per revolution. Flatted shaft. 20mm long, momentary switch.

EC11E18344OC with 18 pulses per revolution. Flatted shaft. 20mm long, momentary switch.

With detents:

EC11E18244AU with 32 detents, 18 pulses per revolution. Flatted shaft. 20mm long, momentary switch.

EC11E15244B2  with 30 detents, 15 pulses per revolution. Flatted shaft. 20mm long, momentary switch.

 

Serrated (knurled). Please check the dimensions of the shaft for proper selection of the knob.

Without detent:

EC11G1574402 - 15 pulses per revolution, momentary switch.

With detent:

EC11G1564411 - 30 detents, 15 pulses per revolution, momentary switch.

For both producers I reccomend study their product selection datasheets which can be downloaded as pdf clicking on their names.

The pinout of the above encoders is compatible with the one in the radio.

I usually like to have longer shafts and cut them to my needs so, if you want a shorter one, just check the datasheets for the part number. 

Both manufacturers are producing compatible encoders for VFO, VOL and FUNCTION. 

 

Simplyfying the code by using a tic-tac machine

Playing with Arduino and it's C++ I often use timed tasks.

Basically, in Arduino you can do things at specific interval either by adding delay() at some strategic points or using wellknown non-blocking code:

const unsigned long interval = 1000; // Interval for LED blink (in milliseconds)
unsigned long previousMillis = 0;    // Variable to store time since last LED update

int ledPin = 13; // Pin for the LED

void setup() {
                    pinMode(ledPin, OUTPUT); // Initialize LED pin as an output
  }

void loop() {

                  unsigned long currentMillis = millis(); // Get the current time

  // Check if it's time to update the LED
  if (currentMillis - previousMillis >= interval) {
                    previousMillis = currentMillis; // Save the last time LED was updated
                    digitalWrite(ledPin, !digitalRead(ledPin)); // Toggle the LED state
          }

      // Other non-blocking tasks can be added here
}
 

What if, the code need more than one timer?

Well, we  can use multiple timers like that!

While this is the simple and easy way, in a big code we start loosing track of what does what and if the code is big, each byte counts! Let's not forget that  each unsigned long type variable cost us 4 bytes of precious memory; each byte consists of 8 bits, and an unsigned long on Arduino is a 32-bit data type, so it occupies 4 bytes (32 bits / 8 bits per byte = 4 bytes).

I have a program in which I have to test multiple timers with multiple distinct intervals and the memory cost was huge.

So, I stayed and think and found a very elegant solution.

While I may reinvented the wheel, I think it is nice to share it with you!

It is all about making a single time measuring function and asign boolean variables to keep track of various things.

  unsigned long previousMillis_ONESECOND = 0; // Variable to store the last time the ONESECOND was flipped

  const unsigned long interval_ONESECOND = 1000; // Interval at which to flip the ONESECOND (in milliseconds)

    bool ONESECOND = false;

void loop(){

    updateONESECOND(); }

void updateONESECOND(){

          unsigned long currentMillis = millis(); // Get the current time

 

          // Check if it's time to flip ONESECOND

          if (currentMillis - previousMillis_ONESECOND >= interval_ONESECOND) {

            // Save the last time ONESECOND was flipped

            previousMillis_ONESECOND = currentMillis;

           // Flip ONESECOND

            ONESECOND = !ONESECOND;

      }

}

then, I have other functions that check various conditions AND bool.

For example, a function that blink a special character on a LCD: 

 

bool ProcessSTART = false;

 

void fLCD(){  // alternate symbol at a rate of one second while StartLog is activated

            if (ONESECOND && ProcessSTART){

                     printFN_Char();

                            }

                else {

                     printFP_Char();

                }

}

the other bool ProcessSART is flipped in other part of the program.

In other functions you can count the number of seconds using this tic-tac function and get other intervals derived from it, using less bytes in a simple arithmetic function.

It's like using an external time generator for all the functions in the code.

Frecventmetru 0-1GHz cu ESP32

Uneori am avut nevoie de un frecventmetru cu precizie ridicata pentru verificarea unor montaje facute acasa.

Cum spatiul pe masa de lucru este limitat, nevoia m-a impins sa caut un echipament miniaturizat.

Sigur ca exista produse industriale dar, unde mai este placerea de a construi ceva?

Un frecventmetru cu ESP32 ar rezolva problema, mai ales ca, teoretic, poate masura frecvente pana la 40 MHz.

Cu ajutorul unui prescaler, gama de frecvente masurate poate fi extinsa, cu mentinerea unei precizii satisfacatoare in pseudo-laboratorul de acasa.

 

 

Schema electrica (click pentru o versiune marita a imaginii):

Cateva precizari:

-Nivelul maxim al semnalului la borne este de 10dbm, adica 10mW/50 Ohm.

-Montajul poate fi simplificat prin utilizarea doar a placii ESP32 si a condensatorului de decuplare la intrarea de semnal dar recomand, totusi, utilizarea unui divizor pentru a proteja intrarea de semnalele mai mari de 3V varf la varf.

Pentru a obtine fisierele .bin necesare scrierii programului, va rog sa ma contactati prin email

 

Programarea unui ESP32 fara Arduino IDE

Placile Arduino deja fac parte din istorie iar hobbystii deja au la dispozitie platforme de experimentare tot mai puternice din punct de vedere al interfetelor oferite.

Espressif a iesit pe piata cu ESP32, un MCU ce incorporeaza periferice IO digitale, ADC-uri de inalta rezolutie si WiFi/BLE, totul intr-un pachet miniaturizat si cu consum extrem de redus ce il face deosebit de versatil pentru proiectele care incorporau pana acum platforma ATMEGA.

Pretul comparabil sau chiar mai scazut al placilor de dezvoltare  bazate pe SOC-ul ESP32 a determinat migrarea multor proiecte spre aceasta platforma iar  IDE-ul Arduino a primit bibliotecile necesare pentru a fi compatibil.

Uneori insa, suntem in situatia de a avea fisierele gata compilate, exportate din IDE Arduino sau alt mediu de dezvoltare si dorim sa facem programarea cu un alt calculator ori am primit fisierele de la altcineva care nu doreste sa faca public codul sursa. 

Cu ajutorul aplicației ESP Download Tool este posibilă încărcarea programelor compilate (fișiere BIN) în ESP.
Acest articol se referă la pregătirea utilitarului și la diferiți parametri necesari pentru transferarea cu succes a acestor fișiere.

Pasul 1, descarcarea aplicatiei ESP Download Tool

Programul este oferit chiar de producatorul Espressif iar descarcarea se face sub forma unei arhive.

Dupa descarcare, dezarhivam fisierele; vom obtine un folder in care se gaseste un fisier .exe si alte subfoldere necesare functionarii aplicatiei.

 

Pasul 2, rularea aplicatiei.

Este de retinut ca aplicatia ruleaza direct, fara a fi necesara instalarea ei. 

Programarea cipului are loc insa pe o interfata UART, seriala, asadar, daca calculatorul nostru nu are port COM nativ sau programarea se realizeaza prin intermediul unui adaptor USB<>UART, este posibil sa fie nevoie sa instalam unele drivere in cazul in care Windows nu le instaleaza automat. 

In general, placile de dezvoltare au deja acest adaptor USB<>UART incorporat in design; in imagine, o placa MCU32 Devkit cu circuitul adaptor CP2102.

Pornim aplicatia ESP Download Tool din executabilul flash_download_tool_3.x.x.exe; se vor deschide doua ferestre; una de tip Terminal (care va afisa datele in timpul operatiunii de upload) si a doua, pentru selectarea tipului de MCU ESP. Cu acest software se pot programa si ESP8266 precum si toata gama ESP32.

 

 

Chip Type: Daca lucram cu un modul ESP32 WROOM (atentie la inscriptia de pe ecranul metalic), atunci selectam
"ESP32-D2WR" iar pentru restul, in marea majoritate a cazurilor putem folosi optiunea generica "ESP32".

WorkMode:  Intotdeauna alegem "Develop". Modul "Factory" este destinat programarii mai multor MCU simultan.

 

Pasul 3, conectarea ESP32 la calculator.

Acum este momentul sa conectam placa de dezvoltare la USB  direct sau prin intermediul adaptorului USB<>UART.

Verificam in Device Manager daca driverul este instalat si functioneaza.

Unele placi de dezvoltare necesita apasarea unui buton in timp ce sunt conectate la USB; acesta este notat "FLASH" sau "BOOT" si nu trebuie confundat cu "RESET" sau "EN"!

Pasul 4, setarile aplicatiei.

Înainte de a selecta fișierele BIN și adresele sectoarelor de memorie, trebuie selectați unii parametri pentru ESP32.
Practic, majoritatea plăcilor ESP32 ar trebui să funcționeze cu următoarele setări:

SPI SPEED: 80 MHz
SPI MODE: DIO
Dimensiunea Flash: 32 Mbit (4 Mbyte)

În plus, trebuie să se specifice portul COM în software.
Viteza de transmisie (BAUD rate) este setată la 921600.
Abia după aceea este necesar să fie specificate căile către fișierele BIN și sectoarele de memorie.

Pasul 5, selectarea fisierelor BIN si a adreselor locatiilor de memorie unde trebuie incarcate.

Programul oferă posibilitatea de a încărca mai multe fișiere BIN în același timp. 

Astfel, nu numai programul propriu-zis, ci și bootloaderul sau partițiile pot fi încărcate în ESP32. 

Deoarece, în principiu, un bootloader este întotdeauna deja instalat pe plăcile de dezvoltare înainte de livrare, in cele mai multe cazuri, acesta nu va trebui încărcat. 

Este suficient să încărcați doar fișierul BIN cu programul principal.

Aria pentru programul principal începe întotdeauna de la:: 0X10000
Ambele câmpuri vor deveni verzi dacă datele au fost introduse corect. 

Cu un clic pe "Start" începe procesul de încărcare. 

Dacă acesta a avut succes, acest lucru este confirmat cu "FINISH" (Terminare). 

De îndată ce se apasă butonul de Reset (sau EN) de pe controler, programul încărcat ar trebui să pornească.

2024, Copyright YO3HJV

 

MESHTASTIC TTGO T-Beam V.1.1 Power On issues

 A few weeks ago, I start to play with Meshtastic using two TTGO - TBeam V.1.1 LoRa boards based on ESP32 MCU.

Because plans are to use them as ROUTER_CLIENT, I choose to recharge the battery using a separate TP4035 module and a solar panel.

Of course, I could very well use the built-in AXP192 battery management but the circuit was pretty unsuitable for small solar panels and the TP4056 offers a more stable configuration. 

In the tests I observed a strange behaviour that can negate the usage of these boards as a reliable remote installed device: 

if the battery voltage drops under the Low voltage treshold, the board will not boot into operating mode.

The same behaviour was consistently observed even the charging was resume on the USB port on the T-Beam board itself.

The ESP32 datasheet have some clues about why this issue occurs and how to mitigate it.

Once the power is supplied to the chip, its power rails need a short time to stabilize. After that, CHIP_PU – the
pin used for power-up and reset – is pulled high to activate the chip. For information on CHIP_PU as well as power-up and reset timing, see Figure 2-4 and Table 2-2.

• In scenarios where ESP32 is powered up and down repeatedly by switching the power rails, while there is a
large capacitor on the VDD33 rail and CHIP_PU and VDD33 are connected, simply switching off the
CHIP_PU power rail and immediately switching it back on may cause an incomplete power discharge cycle
and failure to reset the chip adequately.
An additional discharge circuit may be required to accelerate the discharge of the large capacitor on rail
VDD33, which will ensure proper power-on-reset when the ESP32 is powered up again.
• When a battery is used as the power supply for the ESP32 series of chips and modules, a supply voltage
supervisor is recommended, so that a boot failure due to low voltage is avoided. Users are recommended
to pull CHIP_PU low if the power supply for ESP32 is below 2.3 V.

I run some tests and found that if the above hints are observed, the recovery of the ESP32 from transient voltage induced coma is 100% so a supervisor chip was ordered.

The STM1001 microprocessor reset circuit is a low-power supervisory device used to monitor power supplies. It performs a single function: asserting a reset signal whenever the V_CC supply voltage drops below a preset value and keeping it asserted until V_CC has risen above the preset threshold for a minimum period of time (t_rec).

To be continued...

LATER EDIT:

The STM1001 finally arrived (after three days) and I was eager to test the validity of my rationale.

 

 

So, I installed it on the board; the Vss was soldered on a little island of Copper exposed by a sharp razor and the Vcc was tied to the Source pin of the P-channel NCE3401 MOSFET.

 

 

This transistor is there to protect the board against reverse polarity from the battery.

The RST of the STM1001 was tied to RST of the T-Beam board.

And here it is, the final installation:

Now, for the tests...

There are two distinct situations, depending on how the battery is charged; internal or external.

 

FIRST VARIANT - battery charged internally, using the AXP192

The battery is directly installed on the board and the AXP192 circuit is used at it's full. 

The battery is a small capacity one (1.28 Wh), to be able to have it quicly charged to observe the parameters.

The battery is charged by AXP192.

Going from a flat battery (around 2.5V), the  voltage of the cell, measured at STM1001 Vcc and Vss.

The blue LED is signalling the charging, the voltage is rising and when it reached 3.19V (on my DVM), the RST is released from Vss to 3.2 V (the Vcc of the ESP32).

The ESP32 start to run, the LoRa RTX is sending the first beacon.

This was consistent during a set of 5 tests.

SECOND VARIANT - battery charged externally through a TP4053 board.

The same battery is connected to a TP4053 board with protection and the output of the board is connected to the T-Beam board in place of it's battery.

The AXP192 is not able to manage the charging process because it cannot detect the external power presence.

Therefore, the AXP192 will not start and will not be able to Power On the T-Beam board, at least in the current firmware used for Meshtastic.

Due to the way it works (it is a very complicate process - if you don't believe me, read the AXP192 datasheet) it is mandatory to simulate PEK press (Power Enable Key) after the voltage reach 3.2V which is beyond my scope.

I did some crude tests and it is doable but the solution will be more complicate than the one I am searching for.