Monday, May 24, 2021

Easy module shield -1- (Arduino)

Recently i received another Arduino sensor shield.
It has a reset button and two other push buttons several other sensors.There are some Dupont pins available to add something of your own (e.g. an IR led).

D0( RX see below )
D1( TX see below )
D2SW1 (push button)
D3SW2 (push button)
D6IR receiver
D7(pins with D7 VCC GND)
D8(pins with D7 VCC GND)
D9RGB led (R?)
D10RGB led (R?)
D11RGB led (R?)
D12Led Red D1
D13Led Blue D2
A0Rotation (pot)
A1LDR (Light sensor)
A2LM35 (temeprature sensor)
A3(pins with A3 VCC GND)
A4( I2C SDA see below )
A5( I2C SCL see below )
TX RX(pins with TX RX VCC GND)
ResetReset button
(power)Power Led

Some names that i have seen for this shield are
Easy module shield
Multifunction (multisensor) Shield Arduino Uno
Multifunction DHT11 LM35 Temperature Humidity Easy Module Shield for Arduino UNO
Multifunction Expansion Board DHT11 LM35 Temperature Humidity For Arduino UNO

The interesting of this relative cheap board is that it contains several hardware items to play with as an  Arduino shield so you do not need to wire these components.

Schematics and some examples can be found at

As i have seen several times interesting information disappear i placed a copy of the schematics here on my blog. (For the code there are also other resources). 

Perhaps in the future i will post some code examples and experiments you can do with this shield. With the LM35 i did not play before. Also i did read about some problems with the Infrared led on a version of this shield. So i hope i will find time soon to play with this board.

Sunday, May 23, 2021

Arduino Relay Shield

This blogpost is about the Arduino relay shield from my 2021 May Mailbag.
It contains 4 relays and provides NO (Normally Open) / NC (Normally Closed) interface and leds showing the state of the relay.

It uses I/O pins 7,6,5 and 4 for relays 1,2,3 and 4. 
The screw terminals for the relay contacts. However the terminals from one of the relays is not very safe due to the position near the metal USB connector on the Arduino !

On there is this diagram showing the connections:

One bad design issue of this shield is that some screw terminal pins (J1) make contact with the metal USB connector of the Arduino. So it is needed to add some protect, at least 2 layers of insulation tape is recommended in articles i found on internet!
Working with main voltage (220V) on the screw terminals is dangerous and having a connection to the metal USB connector is asking for problems!
As i want to stay safe i decided to do it different and did put long pin connectors between the Arduino an this shield. This gives more space between the screw connectors and the metal USB as i expect this is really needed for safety. 

To test this shield i modified a simple Arduino blink example sketch.
The interval was extended to 4000 as for the relay a slower on and off switching time would be more appropriate.
Also the pin number was changed to check if the digital pins 4,5,6 and 7 are the correct one's. And indeed this are the channels. When switching the corresponding led blinks and it is possible to hear the clicking of the relay. (also the connection can be measured with ohm meter.)

  Blink without Delay

  Turns on and off a light emitting diode (LED) connected to a digital pin,
  without using the delay() function. This means that other code can run at the
  same time without being interrupted by the LED code.

  The circuit:
  - Use the onboard LED.
  - Note: Most Arduinos have an on-board LED you can control. On the UNO, MEGA
    and ZERO it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN
    is set to the correct LED pin independent of which board is used.
    If you want to know what pin the on-board LED is connected to on your
    Arduino model, check the Technical Specs of your board at:

  created 2005
  by David A. Mellis
  modified 8 Feb 2010
  by Paul Stoffregen
  modified 11 Nov 2013
  by Scott Fitzgerald
  modified 9 Jan 2017
  by Arturo Guadalupi

  This example code is in the public domain.

// constants won't change. Used here to set a pin number:
const int ledPin =  7;// the number of the LED pin

// Variables will change:
int ledState = LOW;             // ledState used to set the LED

// Generally, you should use "unsigned long" for variables that hold time
// The value will quickly become too large for an int to store
unsigned long previousMillis = 0;        // will store last time LED was updated

// constants won't change:
const long interval = 4000;           // interval at which to blink (milliseconds)

void setup() {
  // set the digital pin as output:
  pinMode(ledPin, OUTPUT);

void loop() {
  // here is where you'd put code that needs to be running all the time.

  // check to see if it's time to blink the LED; that is, if the difference
  // between the current time and last time you blinked the LED is bigger than
  // the interval at which you want to blink the LED.
  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    // save the last time you blinked the LED
    previousMillis = currentMillis;

    // if the LED is off turn it on and vice-versa:
    if (ledState == LOW) {
      ledState = HIGH;
    } else {
      ledState = LOW;

    // set the LED with the ledState of the variable:
    digitalWrite(ledPin, ledState);

Conclusion: The relay shield is interesting however some additional safety mods are really needed as one of the screw terminals is located to close to the metal USB connector on the Arduino!

Saturday, May 22, 2021

2021 May Mailbag

May 2021 Mailbag
As i received several items i decided to post this Aliexpress "2021 May Mailbag" already at 22 may 2021. However i am still expecting some more items and i expect some of it also will arrive in may also..   

Protective clips for laptop/smartphone camera.
DIY led lamp
Power on / off switch

Power off switch ( emergency stop switch )
Voltage meter indicator
Some more banana panel socket test probe binding post plug jack connect chassis parts
Arduino GPS shield with SD slot
AArduino relay shield
Another Arduino sensor shield
16 Channel ethernet shield 
pH meter DIY for Arduino 
CR2032 battery holders 

Tuesday, May 4, 2021

Fingerbot -1-

This blogpost is part 1 about the Moes Tuya Smart Bluetooth Fingerbot Button Pusher.  Recently i got the opportunity to buy for 0.01 Eurocent (including shipping) two of these devices on Moes Direct Store on AliExpress. The regular price  is just below 50 Euros, so this is a sponsored blogpost
I was exited to receive these two Fingerbots after 10 days.  The Fingerbot is just a small cube with an arm that can be used to push a button. A 'st├índard usb to usb3 cable is included for charging. (The charger itself is not included). Also a toolpack is included with some connectors to use it e.g. for a rocker switch. As you can see on the photos all came in nice packaging.

Without a a special bridge it can communicate direct over Bluetooth with your phone. With a bridge it should be possible to use Alexa or Google home assistant to control it. This bridge was not included for 0.01 Euro and the standard price for it is around 16 euro.
In this blogpost you will find some photos to get an impression.
Connection with bluetooth using the app was easy. A download link for the app was easy found using the provided QR code. In the app are some configuration options. E.g. for setting the bop and bottom position of the moving arm, Selecting a use mode and setting the sustain time for a mode when on or off should move down the arm, waiting during a short interval time and moving up the arm again. Also you can place an icon with a direct link to the fingerbot op you android screen

How good the Fingerbot would works also depends on how good you can glue it to the system what you want to control.  Some material is included to attach it to however I did not install a Fingerbot it yet.
Most electrical devices can be controlled another way so i did not find an immediate use case to push a switch. A use case  for me could be a more mechanical device like an aerosol air freshener, controlling ventilation, moving the plunger of a syringe.
Unfortunately the ventilation in my home needs a much bigger mechanical move than with the Fingerbot 'out of the box' is possible. Perhaps adding a lever would help, however that also increased the amount of force needed. If it would be easy possible to use it on the ventilation above my windows i perhaps would consider buying even some more.

Summary: Interesting device that i otherwise would not have bought as the current original price of around 25 Euro's is relative high.
After more testing i like to create a second post about this interesting device.