diff --git a/.github/workflows/pr-size.sh b/.github/workflows/pr-size.sh
new file mode 100755
index 0000000..ae555ca
--- /dev/null
+++ b/.github/workflows/pr-size.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+MESSAGE=$1
+BASE_DIR=$2
+PR_DIR=$3
+shift 3
+
+# this assumes we're running from the repository root
+AVR_SIZE=$(echo .dependencies/avr-gcc-*/bin/avr-size)
+test -x "$AVR_SIZE" || exit 2
+
+avr_size()
+{
+    "$AVR_SIZE" --mcu=atmega2560 -C "$@"
+}
+
+avr_flash()
+{
+    avr_size "$@" | sed -ne 's/^Program: *\([0-9]\+\).*/\1/p'
+}
+
+avr_ram()
+{
+    avr_size "$@" | sed -ne 's/^Data: *\([0-9]\+\).*/\1/p'
+}
+
+cat <<EOF > "$MESSAGE"
+| ΔFlash (bytes) | ΔSRAM (bytes) |
+| -------------- | ------------- |
+EOF
+
+base_bin=$(echo ${BASE_DIR}/firmware)
+base_flash=$(avr_flash "$base_bin")
+base_ram=$(avr_ram "$base_bin")
+
+pr_bin=$(echo ${PR_DIR}/firmware)
+pr_flash=$(avr_flash "$pr_bin")
+pr_ram=$(avr_ram "$pr_bin")
+
+flash_d=$(($pr_flash - $base_flash))
+ram_d=$(($pr_ram - $base_ram))
+
+echo "| $flash_d | $ram_d |" >> "$MESSAGE"
diff --git a/.github/workflows/pr-size.yml b/.github/workflows/pr-size.yml
new file mode 100644
index 0000000..ac7075b
--- /dev/null
+++ b/.github/workflows/pr-size.yml
@@ -0,0 +1,68 @@
+name: pr-size
+
+on:
+  pull_request_target:
+    branches: [ main, MMU_* ]
+
+env:
+    TARGETS: "firmware"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+
+    steps:
+
+    # setup base required dependencies
+    - name: Setup dependencies
+      run: |
+          sudo apt-get install cmake ninja-build python3-pyelftools python3-regex python3-polib
+
+    # build the base branch
+    - name: Checkout base
+      uses: actions/checkout@v3
+
+    - name: Setup build dependencies
+      run: |
+          ./utils/bootstrap.py
+
+    - name: Build base
+      run: |
+          rm -rf build-base
+          mkdir build-base
+          cd build-base
+          cmake .. -DCMAKE_TOOLCHAIN_FILE="../cmake/AvrGcc.cmake" -DCMAKE_BUILD_TYPE=Release -G Ninja
+          ninja
+
+    # save pr-size for later use
+    - name: Save base data
+      run: |
+          cp -f ./.github/workflows/pr-size.sh build-base
+
+    # build the PR branch
+    - name: Checkout PR
+      uses: actions/checkout@v3
+      with:
+        clean: false
+        ref: ${{ github.event.pull_request.head.sha }}
+
+    - name: Build PR
+      run: |
+          rm -rf build-pr
+          mkdir build-pr
+          cd build-pr
+          cmake .. -DCMAKE_TOOLCHAIN_FILE="../cmake/AvrGcc.cmake" -DCMAKE_BUILD_TYPE=Release -G Ninja
+          ninja
+
+    # extract/show build differences
+    - name: Calculate binary changes
+      run: |
+          rm -rf build-changes
+          ./build-base/pr-size.sh build-changes build-base build-pr
+
+    - name: Add PR Comment
+      uses: mshick/add-pr-comment@v2
+      with:
+        message-path: build-changes
diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
new file mode 100644
index 0000000..1125112
--- /dev/null
+++ b/.github/workflows/stale.yml
@@ -0,0 +1,30 @@
+name: Mark stale issues
+
+on:
+  schedule:
+  # 1:30 AM on MON/THU
+  - cron: "30 1 * * 1,2,3,4"
+
+jobs:
+  stale:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/stale@v8
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        # Don't ever mark PRs as stale.
+        days-before-pr-stale: -1
+        stale-issue-message: 'This issue has been flagged as stale because it has been open for 60 days with no activity. The issue will be closed in 7 days unless someone removes the "stale" label or adds a comment.'
+        close-issue-message: 'This issue has been closed due to lack of recent activity.'
+        # Don't act on things assigned to a milestone or assigned to someone.
+        exempt-all-milestones: true
+        exempt-all-assignees: true
+        enable-statistics: true
+        # Disable this and change the operations per run back to 30 when this goes live.
+        debug-only: false
+        operations-per-run: 30
+        stale-issue-label: 'stale-issue'
+        stale-pr-label: 'stale-pr'
+        ascending: true