Web Controlled Servo from a BeagleBone Black

bbb_servo

[Babak] created an in-depth tutorial on how he got his BeagleBone Black to control a servo from a web browser.

[Babak] configured a pin on his BeagleBone Black (BBB) as a PWM line and connected it to the control line on a micro hobby servo. The BBB is running a Node.js web server that displays a simple web page to control the servo. The browser sends a WebSocket request to a small WebSocket node server also running on the BBB that then writes the appropriate PWM value to the pin connected to the servo.

The code for node WebSocket server and web server can be found on his GitHub page. There is also a small node library to control PWM lines on the BBB. Though the end result is simple, controlling the servo can be done from any browser that can make a network connection to the BeagleBone Black. Check out the video after the jump for a description and demonstration.

[Read more...]

A Clock That Plots Time

plotclock

[Johannes] just sent us a tip about his small plotter that plots out the current time.

[Johannes] small clock plotter uses a dry wipe pen to write out the time on a small piece of dry erase board. The design is Made of three small 9g servos, with one to lift the pen off the writing surface and the other two to control a pair of connected jointed arms for the x and y-axis.

The little robot painstakingly wipes away the previous time before scrawling the current time in its place (with minute accuracy).

[Johannes] had hackability in mind when creating this project, making sure to keep to standard parts and making the code and design files available. The hardware for the build can be laser cut or 3D printed. The Arduino sketch can be found on GitHub and the design files can be found on Thingiverse. There are more detailed build instructions on Nuremberg’s FabLab page (translated).  [Read more...]

Glue Stick + Servo = Linear Actuator

glue stick linear actuator

What do you get when you cross a glue stick with a hobby servo motor? A linear actuator, of course! Although this could be done with other household implements, the form factor of this glue stick seems perfectly suited to sit on top of a servo horn.

The servo, as you might have guessed, has to be converted to rotate fully instead of the 180 degrees or so that is typical of these types of motors. The trick to this, and what really makes it shine in our eyes, is that instead of attaching two resistors in a normal continuous rotation mod, the potentiometer is used on the glue stick allowing for position feedback.

The resulting force from this gear-reduced actuator is quite impressive, giving an “err” (over 3 Kilograms) on the scale used for testing. [Gareth] or [Chiprobot] gives a great tutorial of how to make one of these after the break, but if you’d rather just see it in action, skip to around 8:20! [Read more...]

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