The Toddler Mobility Trainer (TMT) is a custom-built, open-source 3D-printed mobility device designed for children ages 1 to 8 who need assistance with independent movement (e.g. due to physical disabilities such as cerebral palsy, spina bifida, or developmental delays). Unlike traditional wheelchairs, the TMT is specifically engineered for young children's developmental needs, and is designed for indoor use under the supervision of adults.