Circled equal with same size as \oplus/\otimes with pdflatex

Question

My question

I am trying to make an equal circled of the same size as \oplus or \otimes, etc. I tried to use the solution provided here :

How do I put a circle around an operator?

However, the size of the operators are not the same.

I used as preamble :

\makeatletter
\newcommand\incircbin
{%
  \mathpalette\@incircbin
}
\newcommand\@incircbin[2]
{%
  \mathbin%
  {%
    \ooalign{\hidewidth$#1#2$\hidewidth\crcr$#1\bigcirc$}%
  }%
}
\newcommand{\oeq}{\incircbin{=}}
\makeatother

And, inside the document itself :

  $\oeq$, $\oplus$, $\otimes$

Which is displayed as follow :

As you can notice, the operator \oeq is bigger than the others. Is there a way to get the exact size used by $\oplus$ or $\otimes$ ? Please note that I would rather keep the compilation with pdflatex.

Thank you in advance for any help you may provide.

---

Minimal working example

\documentclass[10pt,a4paper]{article}

\makeatletter
\newcommand\incircbin
{%
  \mathpalette\@incircbin
}
\newcommand\@incircbin[2]
{%
  \mathbin%
  {%
    \ooalign{\hidewidth$#1#2$\hidewidth\crcr$#1\bigcirc$}%
  }%
}
\newcommand{\oeq}{\incircbin{=}}
\makeatother

\begin{document}
\Huge   $\oeq$, $\oplus$, $\otimes$
\end{document}

Answer 1

One solution would be to use the unicode-symbol U+229C for this. For example with the package unicode-math.

% arara: lualatex

\documentclass{article}
\usepackage{unicode-math}

\begin{document}
\[\oplus\ominus\otimes\oslash\odot\circledcirc\circledast\circledequal\circleddash\]
\end{document}

\circledequal or \symbol{"229C} yield your desired symbol in the right size for the most common fonts.

Edit:

As mentioned in comment, the OP wants to stick to PDFLaTeX. For this case, I would choose the binary operators defined in the package mathabx which look even nicer than the default ones (in my eyes). The macro \ovoid yields an empty circle of the size of the other operators.

% arara: pdflatex

\documentclass[10pt,a4paper]{article}
\usepackage{mathabx}

\makeatletter
\newcommand\incircbin
{%
  \mathpalette\@incircbin
}
\newcommand\@incircbin[2]
{%
  \mathbin%
  {%
    \ooalign{\hidewidth$#1#2$\hidewidth\crcr$#1\ovoid$}%
  }%
}
\newcommand{\oeq}{\incircbin{=}}
\makeatother

\begin{document}
\Huge   $\oeq$, $\oplus$, $\otimes$
\end{document}