ESP32 + MicroPython + Mac, Wi-Fi scan example

I have been trying to upload MicroPython to a ESP32 on a Mac. It uses the CP210x serial-to-usb driver, so you need to have this installed before you even bother.

ESP32, an amazing little board.

Flashing MicroPython from a Mac to ESP32

I got MicroPython from the official site, at http://micropython.org/download/#esp32. Current version is v1.9.3-240-ga275cb0f, from January 21st, 2018 (today).

To upload it, I used the NodeMCU flasher tool, which I got from Marcel Stör’s github. It allows you to use a GUI to Flash ESP8266 and ESP32 boards. You might need to install WxWidgets – the python’s PIP doesn’t work, but the brew one works. Easy peasy:

brew install wxpython

And you are good to go:

git clone https://github.com/marcelstoer/nodemcu-pyflasher.git

And follow the instructions on how to build it.

Once you have it, you can try the GUI, but when I try to flash it, I have an error like this:

flash read err, 1000
Falling back to built-in command interpreter.
>ets Jun 8 2016 00:22:57

So, I went to the directory where I cloned it, and ran from the command-line:

python esptool.py --port /dev/cu.SLAB_USBtoUART write_flash 0x1000 ~/Downloads/micropython-esp32-20180121-v1.9.3-240-ga275cb0f.bin

Which gave me a working MicroPython on the ESP32.

Wi-Fi Scan

Making the wifi scan test is a four-liner:

import network
station = network.WLAN(network.STA_IF)

This is the output I get on Arduino Serial monitor, from the reboot to the moment I type those commands (shown in red):

ets Jun 8 2016 00:22:57

configsip: 0, SPIWP:0xee
mode:DIO, clock div:2
entry 0x4007a6c4
[0;32mI (205) cpu_start: Pro cpu up.[0m
[0;32mI (205) cpu_start: Single core mode[0m
[0;32mI (205) heap_init: Initializing. RAM available for dynamic allocation:[0m
[0;32mI (208) heap_init: At 3FFAE6E0 len 00001920 (6 KiB): DRAM[0m
[0;32mI (215) heap_init: At 3FFDCD68 len 00003298 (12 KiB): DRAM[0m
[0;32mI (221) heap_init: At 3FFE0440 len 00003BC0 (14 KiB): D/IRAM[0m
[0;32mI (227) heap_init: At 3FFE4350 len 0001BCB0 (111 KiB): D/IRAM[0m
[0;32mI (233) heap_init: At 4008FC7C len 00010384 (64 KiB): IRAM[0m
[0;32mI (240) cpu_start: Pro cpu start user code[0m
[0;32mI (33) cpu_start: Starting scheduler on PRO CPU.[0m
OSError: [Errno 2] ENOENT
MicroPython v1.9.3-240-ga275cb0f on 2018-01-21; ESP32 module with ESP32
Type "help()" for more information.
>>> import network
>>> station = network.WLAN(network.STA_IF) 
I (42465) wifi: wifi firmware version: 111e74d
I (42465) wifi: config NVS flash: enabled
I (42465) wifi: config nano formating: disabled
[0;32mI (42465) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE[0m
[0;32mI (42475) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE[0m
I (42495) wifi: Init dynamic tx buffer num: 32
I (42495) wifi: Init data frame dynamic rx buffer num: 64
I (42495) wifi: Init management frame dynamic rx buffer num: 64
I (42505) wifi: wifi driver task: 3ffe2d38, prio:23, stack:4096
I (42505) wifi: Init static rx buffer num: 10
I (42515) wifi: Init dynamic rx buffer num: 0
I (42515) wifi: Init rx ampdu len mblock:7
I (42525) wifi: Init lldesc rx ampdu entry mblock:4
I (42525) wifi: wifi power manager task: 0x3ffe852c prio: 21 stack: 2560
[0;32mI (42555) phy: phy_version: 362.0, 61e8d92, Sep 8 2017, 18:48:11, 0, 0[0m
I (42555) wifi: mode : null
>>> station.active(True) 
I (68635) wifi: mode : sta (24:0a:c4:03:a8:90)
[0;32mI (68635) wifi: STA_START[0m
>>> station.scan()
[0;32mI (79565) network: event 1[0m
[(b'FRITZ 6360C', b'\x9c\xc7\xa6\x0cc\xbe', 1, -84, 4, False), (b'WLAN-565914', b'\xd4!"\xe9\xb7K', 11, -92, 3, False)]

I still have to figure out how to write python scripts to the filesystem, haven’t checked on it yet. But I am happy to make it work 🙂



Esp8266 NodeMCU V3 Lolin: Don’t bother!

I made a robot a while ago – it’s pretty much documented here – with a Esp8266 board. It worked beautifully from the beginning. You set up the board on Arduino IDE and you are good to go.

IMG_8682.JPGA wonderful little board

Recently, inspired by a tweet from my genius friend Ugo Sangiorgi about using the ESP8266 as a wi-fi repeaters, I decided to buy a couple more of those boards, in order to cover my house with cheap wi-fi.

Being the cheapskate I am, I went to AliExpress, and bought the cheapest NodeMCU I found: Something called “NodeMCU V3” (the officials are V1 and V2). It costs around 2 euros. Check it here: NodeMcu on Aliexpress

It damn looked like my first NodeMCU. And a Wi-Fi router for 2 euros, albeit a slow one, is unbeatable.

Until they arrived.

This is the little monster:

IMG_8681.JPGEsp8266 NodeMCU V3 Lolin – looks similar to the one above, eh?

As everyone does, the first thing I did was to power it on and try the Blink example. (It comes with a blink one, but anyway). Nothing.

Turns out, the LED_BUILTIN is set to some other pin. If you and to make it work, replace “LED_BUILTIN” on this board with “2”. It works.

Fine. The board looked a bit large, though. I took an ESP32 that I had around and checked. This thing is bigger than the ESP32 that I was whining about a while ago here!

Lo and behold…

IMG_8684.JPGThe damn board VS a ESP32. Notice how the wifi antenna is somehow covered.

It uses the CH340 serial, which seems to be a piece of crap, but hey, 2 euros. I couldn’t care less.

Making the board run properly on Arduino IDE

The serial output is wrong: One has to set


on arduino code in order to get 115200 output on the serial monitor. This is because it uses a 40mhz crystal oscillator instead of the standard 26mhz one. You can fix this with changing the crystal settings at


Just force setting it to 40mhz, around line 87:

    // crystal_26m_en
    // 0: 40MHz
    // 1: 26MHz
    // 2: 24MHz
      [48] = 0,

This SHOULD fix the fact that this board basically has no wifi. Some people have reported partial success on github, but I can’t say the same. I can see no wifi here.

Did I say that this board is huge? Well, good luck using it in a breadboard. It doesn’t leave any room for anything:

IMG_8685.JPGLove playing with your boards in a breadboard? Well FUCK YOU

All in all, I spend quite some days to find the solution for the LED pin and the clock I mentioned above, and I still can’t have any wi-fi whatsoever. The vendor asked if I have googled it (!).

To sum it up, my recommendation is: don’t buy this crap. There are other cheap boards around.

Oh, and when I mentioned the other Esp8266? Here it is one next to the other:

IMG_8679.JPGThe good, the bad and the ugly?

IMG_8680.JPGThe underbelly of the original ESP8266 vs this Lolin whatever

So, again, the links:

https://github.com/esp8266/Arduino/issues/4005 – the talk about the serial output and wifi

core_esp8266_phy.c The file you should change to make it work

A wifi repeater using ESP8266



Running a 5V 5mw 650NM laser from Arduino.

Simple as shit, but as I haven’t found it….

It’s almost the same as the “blink” example from Arduino IDE. One just needs to change the pin (I use ~11), and use analog write instead of digital.

Follows the code:

int laser = 11;

void setup() {
 pinMode(laser, OUTPUT);

// the loop function runs over and over again forever
void loop() {
 analogWrite(laser, 20); // 20:enough. 100: hurt your eyes
 analogWrite(laser, LOW);
 delay(500); // cool it down



Robot car controlled by iPhone using Blynk and NodeMCU.


I created a simple app on Blynk with 4 buttons connected to virtual Pins.

See how to install and run Blynk here.Then, just connect those buttons to virtual pins, like this:


Forward: V0, Backwards: V1, Right: V2 and Left: V3. It look like this:


Got a token for the project and used on the following file on your Arduino IDE.

 * This example runs directly on NodeMCU chip
 * using the Blynk platform and mobile application.
 * Change WiFi ssid, password, and Blynk auth token to run :)

#define BLYNK_PRINT Serial // Comment this out to disable prints and save space
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

#define RightMotorSpeed 5
#define RightMotorDir 0
#define LeftMotorSpeed 4
#define LeftMotorDir 2

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
char ssid[] = "MyWifi";
char pass[] = "MyWifiPassword";

void setup()
 Blynk.begin(auth, ssid, pass);

 pinMode(RightMotorSpeed, OUTPUT);
 pinMode(RightMotorDir, OUTPUT);
 pinMode(LeftMotorSpeed, OUTPUT);
 pinMode(LeftMotorDir, OUTPUT);

void loop()

void halt()
 digitalWrite(RightMotorSpeed, LOW);
 digitalWrite(LeftMotorSpeed, LOW);

void forward()
 digitalWrite(RightMotorDir, HIGH);
 digitalWrite(LeftMotorDir, HIGH);
 digitalWrite(RightMotorSpeed, HIGH);
 digitalWrite(LeftMotorSpeed, HIGH);

void reverse()
 digitalWrite(RightMotorDir, LOW);
 digitalWrite(LeftMotorDir, LOW);
 digitalWrite(RightMotorSpeed, HIGH);
 digitalWrite(LeftMotorSpeed, HIGH);

void right()
 digitalWrite(RightMotorDir, LOW);
 digitalWrite(LeftMotorDir, HIGH);
 digitalWrite(RightMotorSpeed, HIGH);
 digitalWrite(LeftMotorSpeed, HIGH);

void left()
 digitalWrite(RightMotorDir, HIGH);
 digitalWrite(LeftMotorDir, LOW);
 digitalWrite(RightMotorSpeed, HIGH);
 digitalWrite(LeftMotorSpeed, HIGH);

 if (param[0])

 if (param[0])

 if (param[0])

 if (param[0])

Wiring up the shield to the engines and battery is straightforward. Left wheel is “Motor B”, right wheel is “Motor A”, and power goes to “ESP Power”. If you insert a jumper on the “shortcut” on the VIN and VM pins, it will power the NodeMCU from the same power source.



Assembling everything together, the thing comes out like this (click to zoom):

And it runs well:

Right now, this is a dumb machine. I will install some intelligence on it pretty soon 🙂 Besides, I will play with different wheel options and maybe a servo on the front.