I just completed a set of whisker-type sensors for my soon-to-be mobile robot. I had seen several such designs elsewhere on the Web, but each had elements I didn’t like, such as that the antennas were electrified. I eventually arrived at the hybrid design shown below.
In this design, one end of a spring is soldered to a PCB, but the other end is left free to move. A U-shaped loop of wire surrounding, but not touching, the free end of the spring is soldered to the PCB. Then, an insulated probe is inserted into the free end of the spring. When the probe collides with an obstacle, the spring moves and makes contact with the loop, completing the circuit.
Here’s the finished product.
Yesterday, I completed my fifth motor controller board, containing two of Steve Bolt’s Four Transistor H-Bridges The first was an old-fashioned SPST/DPDT relay controller, the second was based on a pair of BA6219B chips I salvaged from an old VCR, the third was a UCN5804B stepper driver, and the fourth was a set of pure transistor (TIP41B) H-bridges. Since I can now control up to 8 DC motors, and since I’m pretty sure I can throw future motor controllers together whenever I need them, I think I’ll move my attention to sensors.
I think I’ll start with such low-tech sensors as bump switches and CdS cells. I like the idea of giving my robot feelers, but I haven’t seen a design for them that I’ve really liked. As for CdS cells, I think I’ll just go with a four-cell design I found in Robot Building for Beginners
I don’t care much for the themes that come with Thingamablog. In my opinion, the one called "trendy" is the least ugly. But I do know that if I were to try and perfect my own theme, I’d never get anything done and eventually get bored and quit before posting a single word. Therefore, I’m going with the least offensive theme for now and won’t try and tweak it until later.
Here we go again. This time, I hope to actually post something once in a while. But I think there’s a chance of that now that I’ve got something worth posting about. And that subject is my crazy project du jour.
You, dear reader, will see the progress of these crazy robotics, linux, or other projects as they unfold. I will also post information that I find useful as I work on these projects.