If you're looking for manga similar to Twin Signal, you might like these titles.
Haruka, the only known survivor of a cataclysmic global war, has taken refuge with a diverse group of sentient robots with distinct personalities. They attempt to survive in the desolate post-war environment; however their supplies are limited and the military robots are still active and hostile. Haruka remains optimistic that other humans may have survived the war, but their persistent search efforts have failed to locate any survivors. Is she destined to live her life without any human contact?
It's said that Thomas Edison stuffed all of his knowledge into his final invention, a screw. Presently, said screw is buried inside the head of Matsunaka Spica, a high-school girl!!! When Matsunaka Spica's thoughts rise to a high enough level, she can create amazing inventions that would normally be impossible to construct!
Louis, a 14-year-old “mecha-geek” who specializes in computers and all manner of hardware, adventures around a post-apocalyptic wasteland in a Dreadnaught tank along with the android-girl Mamet and teenaged ladies Liza, Wooty, and Mill. Though the Great War happened more than three decades pasts, the remnants remain everywhere, and the threat lingers that those who escaped to Mars might return to Earth to remake the planet anew, regardless of whether or not the remaining inhabitants agree. One of the greatest current problems is the atmospheric conversion system Z.P.T., which has gone out of control, but while seeking a solution to that problem there are war robots to be fought, treasure to be hunted down, lost tech to be recovered, and a sexy operative of the Anti-Martian Earth Self Defense Force to be dealt with.
Zip up and get your robot on! A new type of robot-action series! World-famous handsome mechanical engineer Koshiro Tatara and scary-looking musclehead Kaname, these polar opposite twins both fell in love with the same girl's smile. Since then, they compete daily to see which of them can make her smile more. But one day, tragedy suddenly strikes Koshiro...
When schoolgirl Rushiha is suddenly attached by a humanoid robot, a guardian robot named Faust appears out of the blue to rescue her! And why does he insist on staying on as her permanent bodyguard? The answers to these questions lead the unlikely pair on a quest to rescue her scientist father from the clutches of his own creations!