What’s new?
- PCB did work, had a power issues 🙁 Could just be a one off mistake, but didn’t want to waste time debugging because we were having more fundamental control issues with A4988s
- A4988 motor controller were cumbesome, had issues going both directions, switched to l298N, easy to control, resolved issues at the cost of 4 pins on arduino as opposed to 2.
- transitioned to a module based circuit design scheme, which has made it easy to get hardware up and running, and also help isolate power features of design, as well as trouuble shoot circuitry because we can isolate what we know works from what doesn’t. This circuit format is less robust than a PCB but better for its ability too iterate quickly.
- Finalized Fundamental mechanical design for the most part
- Got feedback on where to place registration tool from LAMP feedback session.
- Decided to transition from using 4 solenoids to using 2 solenoids due to a combination of lack of IO/pins depending on how sensors are configured, and unexepected jiggling of solenoid stylus which loosens screw over time. Think this issue can be mitigated with lock tight
- Learned about detent current, which can cause stepper motor to torque despite coils not being energized. Was worried we would have to get a new stepper which wouldn’t arrive until Friday. on a whim designed to power each coil to try to untorque motor, and it worked!
- Made a test version of ir sensor
- think we need to transition to LDR
What next?
- Finalize and get light sensor working
- tune vertical height on solenoids
- mount braille directives
- learn why detent current gets triggered sometimes