Arduino uno development board vs Atmega328p au standalone chip

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I have been using arduino uno development board for a few months now and wanted to shift to a smaller version of the same. For this, I used Atmega328p AU standalone chip using an I.C. socket (schematic). The schematic doesn't show 22pf capacitors with the crystal I have used.

Everything worked fine till the time I was using my mac to power the circuit. But when I use the wall socket to power my circuit, the setup starts misbehaving whenever I operate (turning switches on or off, rotating the fan regulator knobs to change fan speed etc.) any switch on the switch board to which the wall socket is plugged in. Whole setup isn't related to any other switch or regulator. It is just connected to the 5v wall socket adaptor which I have plugged in the board as shown in the picture below. Whenever I turn the switch on or off or turn the regulator knobs, I think some spikes/surges are ingested through the adaptor. The whole setup just starts resetting regularly or most of the time freezes altogether. However, the problem doesn't show up in the Uno development board plugged into the same adaptor using 5v and GND pin. I do not understand what is making the difference between the two. Is there a need for some decoupling or isolation?

Things I have tried:

  • Changing the cyrstal
  • Changing the 22pF capacitor with 18pF ones.
  • Uploaded the blink code in both Arduino Board and the chip, still the same problem persists. The blink code and my code both work fine with the Arduino board but on the standalone chip it gives the same erratic behaviour (LED stays on i.e., the code freezes).
  • Rewired the whole setup multiple times.

Following is the pic of the setup

960×1280 152 KB

At the left bottom of this image, the two wires I am holding show the 5V power input to the breadboard circuit. Note that I have given the input to the 5v pin of the chip and not vcc (because it works fine bypassing the voltage regulator).

The fan speed regulator knobs are not connected to the arduino. The only link is the adaptor, I suppose.

2

A photo of the hardware does not provide a clear indication of the connections. Please make a pencil drawing showing all the connection and post a photo of the drawing.

Maybe your wall-wart is not adequately regulated? Will your Atmega run from 3xAA cells?

...R

3

Robin2:
A photo of the hardware does not provide a clear indication of the connections. Please make a pencil drawing showing all the connection and post a photo of the drawing.

Maybe your wall-wart is not adequately regulated? Will your Atmega run from 3xAA cells?

...R

  • I have provided a schematic for the same in the start of the question.
  • I have tested with a regulated supply with through USB port of my laptop. It gives the same problem when I am charging the laptop while powering the circuit.
  • My problem is shown only on the standalone 328p AU chip. I want to know why is it not showing in the arduino uno development board.
  • I have a home automation project and using a battery supply is not feasible. Is there a way in which I can rule out the problem from the existing circuit.
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spycatcher2k:
If your chip is in the holder at the top of your picture, and the components are on the PCB at the bottom, then that's your issue. Capacitors should be as close to the chip as possible, the crystal should also be very close.

I have tried the same setup with the pu/DIP IC, but the problem still persists. In that case, I have kept everything very close.

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Sorry I missed the link to the picture. Here is is for the convenience of others

...R

7

Does the bootloader connect to Power & Gnd as well? Or at least to Gnd if the board is powered from other means during bootloading?

8

I'm pretty sure that same image appears in another current Thread from a different member.

I wonder if it is an image of how the Atmega should be connected or an image of how it is connected?

Also it seems to be an image of an SMD chip whereas the photo of the breadboard implies a DIP version ?

...R

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CrossRoads:
Does the bootloader connect to Power & Gnd as well? Or at least to Gnd if the board is powered from other means during bootloading?

Yes, the power and GND are going through arduino's 5v pin only during bootloading. The rest is shown in the schematic only.