Aaron Hasty<p>Cerberus KVM: custom 3‑monitor & USB switch control via RS‑232</p><p>I built a setup to seamlessly switch input on three monitors and USB devices using RS‑232. Started with a dual‑monitor KVM and a single‑monitor KVM with RS‑232, then hacked apart USB switches and used an Arduino + TTL‑to‑RS‑232 to control them via serial commands.</p><p>Chained devices on one RS‑232 bus: dual‑monitor KVM, HDMI switch, USB switch—no interference. Designed a custom controller (3 toggle switches + 4 input buttons + OLED) to select inputs per display and manage USB focus.</p><p>Faced challenges: Arduino memory limits in display library (resolved by swapping to a lighter OLED lib), and CNC fitting issues for housing. But after some adjustments, everything fit into a case, soldered and wired cleanly.</p><p>Result: reliable daily control—switch HDMI and USB across 3 monitors with a single physical interface.</p><p> <a href="https://techhub.social/tags/WhatsOnMyDesk" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>WhatsOnMyDesk</span></a> <a href="https://techhub.social/tags/desksetup" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>desksetup</span></a> <a href="https://techhub.social/tags/WeirdDeskThings" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>WeirdDeskThings</span></a> <a href="https://techhub.social/tags/WorkFromHome" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>WorkFromHome</span></a></p>