Friday, September 18, 2015

NodeMCU breadboard aid

Before I go on with this story I will tell you what the NodeMCU is.

Since just over a year there is a hot product on the market and that is called the ESP8266. This tiny chip has a processor (running at 80 Mhz), memory, I/O pins and best off all WIFI. The number of the pins depend on which type you purchase.

The ESP8266-01 has just 2 I/O pins. Not a lot but enough for a button and a led or a sensor and a led etc. etc. And yes there is enough memory in it to adresa a whole bundle of Neopixels.
The largest one (at this moment) is the ESP8266-12 which has 11 digital I/O pins and 1 Analogue input.

So the great part is that you can use it as you would use any micro controller (AKA Arduino)  but you can control the I/O pins over the internet or you can read the I/O pins over the internet. That makes it very usefull for many projects.
Oh, and did I mention that it costs just 3 to 4 dollar/euro !!!!

Any drawbacks ??

Yes. The chip is not breadboard friendly as the spacing of the pins is different and there is no USB connection like the Arduino's have. And they operate on 3.3 volts.

And that is where the NodeMCU comes in.
It is the ESP8266-12 (so the most extensive version) breadboad friendly with an USB connection. Ideal for all kinds of projects.
And just a bit more expensive. It is in the range of 6 to 8 dollar/euro.

Breadboard friendly ??

Well not exactly. look at the pictures below.

As you can see the NodeMCU indeed fits on a breadboard. Now look closer:

Ha there is no room left to put breadboard cables to attach leds, buttons, sensors, servo's etc. The NodeMCU is just as wide as the breadboard itself.

You could decide to put just the right side of the pins on the breadboard and leave the left side floating in the air like the next picture shows you:

This will work and I must admit that I have used it for some purposes. There are however some flaws.

Indeed all digital I/O pins are on the right side of the board so you can access them all. The GND and 3.3 volt are also accessible on that side of the print. Sufficient for most projects.

However the 5Volt power line and the Analogue input are on the right side of the board and therefore not accessible at all.

There is a new release of the NodeMCU (version 1.0 and up) which is smaller and leaves room for 1 row of breadboard pins on both sides. Better but not yet what we want.

The solution

So what I did is I made myself a small PCB with female headers.

There are 4 rows of female headers on the PCB, The inner ones is where the NodeMCU will fit in. The outer ones is where the breadboard cables will fit in.

As I used stripboard with long rows the soldering was easy.

Just measure where the rows of headers should be positioned and solder them in place.
Next cut the long PCB rows in the middle so no connection is made between the right side of the pins and the left side.

Next step.

Thoroughly test if there is no short circuit between the rows of pins and test if there IS a connection between the header where the NodeMCU fits in and the headers where the bereadboard cables fit in. Do this well and you avoid problems when designing your project.

Now but the PCB to size and ready we are.

Here you can see the NodeMCU next to the breadboard.

And this picture tells it all.

I will be getting more into the ESP8266 in future stories so stay tuned.

Till next time
Have fun

Luc Volders