Hey guys, in this tutorial I will show you how to make a receiver that we will be able to use for our Arduino based drone. You will be able to find the circuit diagram for the receiver below. In our previous posts, I showed you guys how to make a professional look PCB using the etching process and applying a UV solder mask to it. We can use the same technique to make the PCB for the receiver also. Go through this POST here. You will find the PCB design and the schematic for the receiver below.

If you guys are not making the PCB, you can also use a prototype breadboard to make it. Use something wires to make the connections for the signals and use a little thicker wire for the power supply. Our receiver will not take to much current. Only the flight controller will draw the current due to the starting of the motor. Also, you might want to avoid soldering pins on the Arduino to make the connection as this will add weight to the circuit. Try to solder the thin wire directly to the Arduino board for the connection. We cannot afford to make the receiver too heavy as the brushed motors are not powerful enough to lift heavy objects. If you have an electric balance, try to weight all the components you are using and keep the overall weight around 80 grams or below.

Now, if you have chosen to make the PCB yourself and it is ready, use a 1 mm drill bit to make the holes. I usually make the hole using a hand drill. If you have a table drill it will be more advantageous for you as you will have better precision. Now, take the Arduino in which you have already soldered all the pins and put it on the PCB where it should be located and solder it. I usually solder only the pins that make connections in the circuit. I have left the unused pin unsoldered. This is done normally to save some weight.
Now you will need to add the NRF module. Do not in any situation solder the pin of the NRF directly to the board as excess heat will blow up the NRF module which will make it useless. Always use a female header to connect the NRF to the Arduino. Solder the female header to board.

Note: I am not connecting the 3.3V voltage regulator for the NRF as it has a very high voltage drop, around 0.9 to 1.3 V which is not good for the circuit since we are using a 3.7 V lipo battery to power the entire board. I am connecting the NRF module directly to the VCC of the Arduino. The Arduino has a 5 V voltage regulator. If we supply the board with 3.7 V, we will have a voltage drop at the VCC to which we can directly connect the NRF. It is not a safe method. You should probably use the HT7333 voltage regulator which has a very low voltage drop, around 90 mV. I have connected it directly to VCC and I have not experienced any problem till now.

So if you have already made the connection for the female header, always add a capacitor of 10 uF to the VCC and ground of the NRF. This will smooth the voltage and prevent the NRF from blowing up. Remember to remove the NRF from the header before doing all these things. Any wrong connection or heat from soldering iron can damage the NRF.
Now that you have already connected the Arduino with the receiver, the receiver is ready. You can power it up, upload the test code and see if it is receiving the signal.
You will find the receiver and transmitter test code here: Receiver and transmitter code
Connect the 3.7 V battery to the Arduino. Connect the positive of the battery to the RAW of the Arduino and the negative of the battery to the GND. You should be careful when connecting the battery to Arduino. Reverse polarity can damage the Arduino which will make it unusable. It can also damage the NRF if it is already connected to the Arduino. Always use connectors for battery connection as it is designed to be able to connect the battery in on direction.

Now connect your FTDI programmer to the board, and upload the code. Once it is successfully uploaded, open the serial monitor. Now turn on your transmitter and see if you can receive the data from the transmitter. You might want to reset both the transmitter and the receiver when performing the test. Just press the reset button on the Arduino for both of them. If you still cannot receive data, there can be a problem with the connection. Make sure to check all the connections or perform a continuity test on the track to make sure everything is good. You might change the NRF also too see if it is working. You might have got a damaged NRF while purchasing. If everything works well, you can now solder thin wires to the board for the connection with the flight controller.
You can find useful images below for better understanding.


Make sure to watch the video on youtube for better understanding.