Will Jessop's Writings

Sailing, Food, Programming, Technology, and other things
Do you have a Ruby on Rails application you'd like to be faster, more scalable, or just upgraded safely? I'm currently open to new contracts doing Ruby on Rails and Postgres scaling and performance work, and Rails upgrades. Contact me at will@willj.net to get started.
| tags:robotics electronics tech

Prototype lifter arm

I added a prototype lifter arm to my robot yesterday. It needs re-doing (it’s unreliable and heavy) but it works for now.

I’m using a new motor driver circuit for it as I burned out the SN754410 motor driver I was using, the lifter motor seems to peak briefly at about 1.5 amps when starting to lift the arm, and that’s out of the chips range. I stayed up late making a new motor control circuit with a L298N that can provide a lot more power.

Here is the robot picking up 12 ping-pong balls. I was driving, Morwenna was filming:

Here is the same run seen through the on-board camera. Almost all of the run was done watching the live feed rather than watching the robot itself:

Here is the paper strip-board design for the L298N circuit.

Designing tHe motor driver circuit for stripboard

Designing tHe motor driver circuit for stripboard

Testing the circuit out on breadboard:

A mess of wires and breadboard and stripboard

Wire everywhere, as often happens when I'm doing electronics projects

A finished circuit on stripbord

The finished circuit. You can see it bolted to the back of the robot in the video.