Problems with Using RC522 and Linear Actuators on a Standalone ATMega328P Circuit

[gmrtnz]

I’m working on a project which could basically be described as an RFID locker. it uses an RC522 RFID reader, and a 5V Dual-channel low-level trigger relays to control two linear actuators. During breadboarding, the ATMega328P is still connected to the Arduino board and the circuit and my code works as intended. Unfortunately this is an academic project and I am required to remove the ATMega328P from the Arduino board and make it a standalone circuit. Little by little, I made the standalone circuit up to where the output of the dual-channel relays were connected to LEDs, and it would work as intended. The problem is, when I connect the linear actuators, the circuit comes in to problems such as the RFID reader would not read any input anymore.

My power source in the standalone circuit would be a 12v 9A lead acid battery and I use a LM2596 to regulate the voltage at 5V. The relay load is connected directly from that 12v source to power the linear actuators.

I would connect the linear actuators to the relays as in this video (even in the standalone circuit):

Controlling a Linear Actuator with an Arduino and Relay

The linear actuators I use are looks also the same as in the video above. My circuit works as intended when the ATMega328P is on the Arduino board so I’m sure that there is no problem with my code.

The current schematic diagram for my standalone circuit looks like this:

My question is, is there something missing from my standalone circuit? My standalone circuit works as intended when the relays' output are connected to LEDs. Am I missing components that I need to connect first before connecting the linear actuators? Do I need to replace the linear actuators instead?

A description on how my code and circuit is supposed to work: A push button is meant to be an input to determine if the locker door is closed. When it is pushed, the linear actuators will actuate their rods. Then,the RFID reader waits for input. An unrecognised tag will make a red LED flash, while a recognised one will make a green LED flash and the linear actuators will retract.

[gilshultz]

I cannot comment at this point as I do not watch videos nor do I see the schematic I need to look at since this is standalone it will be on its own PCB. Posting links to technical information on each of the devices would be much more helpful to me then a video.

[gmrtnz]

Hello.

This is the current schematic for the RFID locker. I've only been making this circuit on breadboard because I want to finalize the circuit before I make the actual PCB.

The 12V dc linear actuators I use looks like this:

[gilshultz]

Thanks. You are taking the correct approach by breadboarding it first. When you get that done you will have working code which will go a long way in debugging your finished board. Your schematic needs work, there are no capacitors which the regulators require as does the processor for bypassing. Check the appropriate data sheets to get values. Be sure to check the data sheet from the regulator manafacturer. They may have the same number but they are not exactly the same. I do not see a reset circuit. The relays cannot be driven directly, you need to use some isolation to drive them such as a transistor, MOSFET or an opto circuit.

One trick to save hardware is to make every unused pin an output if possible and write it low. This will eliminate the need to terminate the pin. Put a note on your schematic so when it is being reviewed they know it was not forgotten. Inputs (pins that cannot be an output) I usually tie together and pull up but check the data sheet to be sure.

If you have some time take a look at KiCad, it is free and it will take you from this point through the Gerber files needed to make the PCB.