Hello guys! Ok have you bought everything? Do you have all the material for your hands? So let’s see how to mount everything together in just a few steps.

First of all you should have everything you need explained in Part One of this miniseries:


If you want to start trying to mount the circuit you can do everything except the connections to the pumps, on the circuit with the integrated there are LEDs, which will turn on when the pump should be in action. In this way you can already test the whole operation of the Dosometric Pump.

The tools necessary for assembly are the following:


or a welder, of the tin, a heat-shrinkable sheath and of the wire, possibly black and red :). Ah of course you also need a screwdriver.

If you do not have a welder you can buy this, it is a great kit that is great for starting:

Soldering Iron Kit

If you prefer to buy a little better, you can take this:

Digital soldering Iron Station

To make holes in the electrical box, such an instrument can be convenient:


We begin to make the cables to be welded to our heads. Cut a black and a red cable of about 10 – 12 cm for each head we are going to mount. In this tutorial I will create a 3-head pump and then I will have 6 cables.


Strip the 2 ends as in the picture and go and attach them to the head of the dosometric pump. Always maintain the same configuration, for example in this photo the red will be towards the bottom of the head.


Then go on to give a solder point to avoid the wires coming off.


At this point, cut 2 pieces of the heat shrink tubing to cover the contacts and welds:

10 11

Put them in the threads and heat them with the lighter so that they adhere well to the contacts: At this point, cut 2 pieces of heat shrink the tubing to cover the contacts and welds:

12 13

Repeat the entire procedure for each head of the dosometric pumps in order to obtain the following result:


now take the 12v – 5v power converter:


Also in this case you have to weld the wires in the 4 points indicated. Use a red wire for the pin with the word In + and a black one for the one with the text In- then cut one end of the dupont cables and solder that end to the pins Out + and Out-. In this case I used a blue thread for the out + and a purple thread for the out-:


Now let’s take the connector for electric current with 2 wires, one red and one black:


Connect the red to the MOST INNER pin and the black to the most EXTERNAL pin;


Also in this case, give 2 welding points and use the heat shrink tubing to cover the contacts:

21 22

Let’s now proceed to pierce the electric box, everyone can use the method he believes, the most comfortable as I said is surely to use that tool that I have linked above, otherwise you can also do it with the drill and then with a rasp, or in any other way you feel more correct. There are 1 holes to make for each head of the dosometric pumps and 1 for the electrical connector we have just soldered:


The end result will be something like this:

22b 24

Now we just have to insert the heads and the connector in the holes just made and proceed with the connections:


Cut again one of the ends of 3 dupont cables (possibly two black and one red) and connect together all the red ones you have, including the one coming from the converter and the one of the newly cut dupont cable:


The blacks of the pump heads are not yet connected together. You only need to connect the black of the power connector with the black of the converter, and with the 2 dupont cables just cut:


In the case of 3 heads you will then have 6 red cables all connected together and 4 black cables all connected together. If you want to do a good thing, use a mammoth to isolate them from the rest:


Now take the circuit with the stepper motor and CUT it, cut the cable that connects the motor to the circuit (The motor will be useless and therefore you can safely throw it):


Take the part with the connector and the wires, and connect the blue wire to the black of the first dosometric head, the pink to the black of the second dosometric head, the yellow to the black of the third dosometric head the orange to the black of the fourth dosometric head. If you have more than 4 heads, you must build the circuit yourself as per the diagram shown in the previous part, or use 2 of these circuits.


Isolate the 3 links as you see fit, with a solder point, or with mammoths. I used 3 pieces of heat shrink tubing:


Now you need to adjust the output voltage from the 12v 5v converter. By connecting the power supply to the connector, the LED on the 12v 5v converter should light up:


Now with a tester (multimeter) you have to put the positive pole on out + and the negative one on out-, set the tester on Vcontinua and measure the output voltage. With a small screwdriver turn the screw until the tester measures 5.00V at the output. I recommend, if you skip this part and / or the output voltage is higher than 5v you will burn the Nodemcu:


Now you need to make all the connections, but first disconnect the power supply from the connector so as not to have power:

First of all, connect the converter outputs to the nodemcu, the red on the Vin pin and the black on a GND, then connect the red dupont cable coming out of the red group at + of the circuit with the integrated and a black dupont from the group of black al – of the integrated circuit. Then connect the other black dupont to another nodemcu GND:


Now connect with 4 dupont cables the pins D1 D2 D5 D6 of the nodemcu respectively to IN1 IN2 IN3 and IN4 of the circuit with the input:


Et Voilร ! Theoretically you have finished. Now try to see if by connecting the power supply some LEDs light up and no smoke comes out anywhere ๐Ÿ™‚

Finally you should get to something like this:


If everything works, we just have to jump to part 3 of this tutorial to load the program on the pump.

I hope I was clear enough, if there were any doubts, don’t hesitate to contact me. Always keep in mind that I do all this without profit and therefore if there are errors or inaccuracies do not kill me.