Month: June 2017

Sparky rewamp (V2)

  By , ,

I had a few issues with the current way Sparky was built. Mainly the the fact that the power bank did nearly not fit and had the motor axis sometimes grind against the hull of the power bank. That is obviously quite a flaw – especially since that also impaired Spary’s movement sometimes. I decided I wanted to get a fixed battery pack, inspired by other creators in the LetsRobot community.

And while I were at it, I wanted to have a better speaker setup.

Here a before/after comparison:

It should be quite obvious that the new revision is now more pleasant to look at. Also the big speaker block could be fit behind the camera and centered, which also improved driving straight. The gripper got the pads to reach all the way to the floor. (I later trimmed the front edges of those so they wouldn’t get caught up on ledges as often) The battery has been replaced with a Li-Ion pack that outputs 12V. With this addition I used two step down converters, but gained the ability to have components that required over 5V – also charging and switching the robot off got way easier.

Here a gallery with more angles and steps.

Cardbot V2

  By , ,

Alongside Sparky’s upgrade I thought I want to iterate with what I learned so far on cardbot as well. I made a few changes already. The biggest one being the Tilt head I implemented for a time.

For that I first tested an old Mindstorms LEGO motor that I had lying around.

And once I confirmed that it worked, I strapped it below the cardboard cover and expanded the hole for the camera in the front. The result was a camera with the ability to look up on command. (since that is a simple DC motor I limited that to a “look up” function that lasted around a second) bundled with the LED I strapped on the Webcam, this improved the field of vision of Cardbot immensely.

Also note on this picture: I needed to add a second Motorhat so it could run the LED + LEGO DC Motor. Luckily those hats are stackable up to 64 in theory because they’re based on l2c.

But this didn’t last long. I wanted to improve it even more. What bothered me the most was that Cardbot didn’t have a gripper like Sparky did already. So I gave Cardbot a whole rework.

First I had to change the Headlight wiring, since I wanted to control that with a pin of the RasPi. That way I wouldn’t need a second motorhat solely for the LED which would be obviously overkill. So I wired in a transistor to feed the power source seperately from the RasPi pin to protect that.

This time I added a Pan/Tilt head for the camera and added the gripper seen in the pictures. For the gripper I needed to make space since it is designed to get pulled by the actuator rod and as a solution I put everything a bit higher up. This way I could also create my own screw holes since the material I used is soft plastic. So I just used the hobbyist knife to carve out screwholes.

And I had to switch to a normal RasPi camera module to be able to move it around like that. while it worked like a charm, I soon noticed that the ziptie and tape mounts on this bot are not the best solution…

Catapult for Sparky

  By , , , ,

In effort to make interactive “Toys” for my robots I created with a catapult built for my LEGO Mindstorms robot back in the day.

I used a LEGO DC motor with the cable I prepared for Cardbot initially, and used a role of tape to weight down the base of the contraption. On the Breadboard I used an ultrasonic distance sensor to enable the robot to shoot the catapult. The logic is handled by the arduino and the simple H bridge to power the DC motor externally to protect the arduino.

Here a small video of it in action: