My First Motion Sim: Scale Model 3DOF Rig (RC Servos + Arduino + SimTools)

Hi everyone! After years of procrastinating, I finally dove into the motion sim rabbit hole. To ease in (and not draiwn my wallet right away), I started with a scale model rig. The idea is just to get my hands dirty with the basics before attempting a full-size build.

It took me four days of tinkering and scavenging through old parts to make this little 3DOF prototype came alive! It’s powered by RC servos, an Arduino clone, SimTools, and @eaorobbie’s classic RC model code (originally 2DOF, which I tweaked into 3DOF).

Hardware Highlights

1. Roll & Pitch: Two mini servos rescued from a 10-year-old RC heli, along with its swashplate and link rods.
2. Yaw: A third GWS servo from my son’s high school project (12 years ago!).
3. Frame: Built from a broken BAVIN PS24 car phone holder. The clamp works surprisingly well as a platform for mini seats, planes, or cars (I’ve got a Lego car on it for now). The plastic ball joint tightener removed for free motion. The swashplate is bolted underneath. Rubber bands help balance out the rod play.
4. Base: An old rotating turntable plate for yaw, mounted on a chunk of MDF salvaged from a computer desk. Stick-on studs keep it from sliding.
5. Electronics: Arduino clone (Alexan ACEduino 328, IDE v1.0), jumper wires, breadboard, USB cable, servo arms hacked from scrap plastic, a Tamiya FWD motor housing as a pivot base, plus a healthy dose of zip ties and double-sided tape.

Software & Testing

• Future goal: Full-size 3DOF rig for MSFS 2020/2024.
• Current tests: Running in Live for Speed with SimTools.
• The demo video shows the model responding to DOF sliders and in-game motion — roll, pitch, yaw, sway, and surge. (I'll upload the video as soon as I'm allowed to)

Current Quirk
The yaw axis occasionally spikes about 45° before snapping back. Could be worn-out servos, loose wiring, or maybe my SimTools axis tuning (min/max or limiting). Axis total is capped at 100%, but it still happens. I also added safety limits in the Arduino Sketch, but not sure if it worked:

// Safety limits to avoid servo binding
const int kMinSafe = 30;
const int kMaxSafe = 150;
​

If anyone’s seen this before, I’d love some pointers!

Thanks for the warm welcome — feels great to finally stop lurking and join in. Excited to learn from you all and (someday) build the real rig!

Mabuhay (Long live)! from the Philippines.

Dargelis