Hey guys, in our previous post I showed you the circuit that we
will need for the Arduino based RC transmitter and receiver that we are making.
However, there was some confusion in the circuit. So, in this post, you can
find a clearer circuit of the Arduino transmitter and receiver below and also
see the part list I have used in this project. If you want to see the coding,
please refer to my previous post here.
Note also that I have made some more changes in the transmitter
circuit which I have not shown below. The change is that I have added a buck
converter in the circuit to power the NRF module. I was previously using the
3.3V from the Arduino to power the NRF module. However, this was not able to
deliver enough current for the NRF with the antenna to work. I am powering the circuit
with a 7.4V lipo battery. I have connected the input of the buck converter to
the 7.4V battery and then I have adjusted the voltage to 3.3V using the small
potentiometer. Once I got the 3.3V, I have connected it to the input of the
NRF. Now make sure you always adjust the voltage before connecting it to the
NRF else if the voltage is higher than 3.7V, it will blow your NRF. So, it is
very important to do it like that.
You can see the picture where you can see I added the buck
converter. For more details about it, you can refer to THIS site.
Part lists:
Transmitter
1. 1 Arduino nano (ATMEGA 328P): Link here
2. 2 toggle switch: Link here
3. 2 Joysticks: Link here
4. 1 NRF24L01 module: link here
5. 1 potentiometer: Link here
6. 1 battery (9V) or sets of batteries equivalent to 9V
7. 1 battery holder
Receiver
1. 1 Arduino nano (ATMEGA 328P):
2. 1 NRF24L01 modules: Link here
3. 2 LEDs: Link here
4. 2 330 ohms resistors: Link here
5. 1 coreless dc motor(7x14): Link here
6. 1 Mosfet P0903BDG: Link here
7. 1 10K ohm resistor: Link here
8. 1 Schottky diode 1N5819: Link here
NRF24L01 DIAGRAM
Transmitter circuit diagram:
Receiver Circuit Diagram
Now I am using the Arduino nano for the transmitter because
it is very small and will make it perfect for the transmitter to be portable.
However, it has a USB port that is made of metal which adds some weight to it. So,
if you are making a very light drone, this would probably be a bad choice. For
that reason, I am using an Arduino pro mini for the receiver part if I intend
to make a drone from this receiver. Arduino pro mini is very light. However, we
cannot program it directly using the USB cable. We have to use an FTDI programmer
for that. We just have to plug it to the pins of the Arduino and upload the
code and you can remove it as soon as the code has finished uploading.
Also, make note of the MOSFET I am using. This type of MOSFET
is N-channel. As we are using it to control the speed of a motor, we know that it
will draw a lot of currents. The coreless motor that I am using will draw a
maximum of 2A which is most of the MOSFETs can handle. However, if you are
using bigger size motors, you should always check the continuous current that
the MOSFET can handle. Suppose we are using a MOSFET that is rated at 2.5A and
we are running a motor that is drawing 2.5A. Our MOSFET will get really hot. If
our motor draws even more current than that, it will blow it. So always make
sure to check the datasheet before selecting MOSFET.
Now another thing to point out is that we are going
to use the PWM signal from the Arduino to control the speed of our motor. You guys
must already be familiar with it. If you don’t know about it, then a brief
explanation would be that we can control the voltage by switching it on and off
very fast. The speed should be around 120 times per second which is almost impossible
to do manually or mechanically. So, we use an electronic device for it that acts
as a switch to which we have full control and that is MOSFET. Now note that the
MOSFET is a function of Voltage, unlike BJT which is a function of current. That
means, the higher the voltage we add to the drain, the higher the voltage will
be to the gate and source of the MOSFET. PWM signal is used to control the voltage
at the drain by controlling its Duty cycle. Now that is a whole topic in
itself. We will discuss everything you need to know in another post.
I hope the diagram is clearer now. Put a thumb up on my youtube video and subscribe.
3 Comments
circuit is not clear to me
ReplyDeleteI need proper code
ReplyDeleteCan I connect transmitter to simulator?
ReplyDeleteThank you
Post a Comment