Sensors or other ?

[JI_YI_MI]

Hi !!!

By seeing all the other manufacturers creating sensors, I would like to know if ROBOTIS envisaged some sensors or extension for its bioloid.

Thank you for your assistance

[JonHylands]

I don't know what Robotis is doing with respect to sensors, other than the AX-S1. I am planning to build a 5-axis IMU to aid in dynamic balance. This IMU sensor will be plugged into the bus like everything else, and will be accessable in the same manner as any other device on the bus.

I will be using this IMU:
http://www.sparkfun.com/commerce/produc ... cts_id=741

I am developing a custom PCB that fits underneath this board (same footprint), that has an ATmega8 on it. Depending on what people want, I may also add a one-axis gyro to make it a full 6-axis IMU.

I will be posting source code for the AVR, the PCB layout, and a parts list for it once it is done. I may, if there is demand, have a bunch of the custom PCBs printed and put together, which I will sell more or less at cost.

Here's a pic of the current PCB layout - I need to add a big cap somewhere for general damping, plus a crystal for the ATmega8 and whatever other support stuff it needs.

- Jon

http://www.bioloid.info/tiki/show_image.php?id=24

[billyzelsnack]

Whoa.. That's a LOT cheaper than the last time I looked.

[JonHylands]

I started a new wiki page for this IMU sub-project:

http://www.bioloid.info/tiki/tiki-index ... is+Bus+IMU

- Jon

[billyzelsnack]

Looking good. I was planning on using 3 RC heli gyros. Used cheapo ones go from $20 (gws) to $40 (telebee) for an ok one, to $95 (gy401) for a nice one. Maybe this makes more sense though. Still, I am wondering if the heading hold feature on heli gyros would be useful. Though. I guess there is nothing stopping me from implementing it myself on the uC.

from.. http://members.toast.net/joerger/gyro.html

A heading hold gyro (sometimes called a 'tail lock' gyro) keeps track of rotation to sense how far and how fast it has turned. It also tracks how much steering input has been received from the radio system. If the two don’t match up, it sends a direction change signal to the servo or steering mixer to correct the turn rate and keeps sending it until the correct heading is regained. Perfect for getting your two-wheeled ‘bot under control.

[JonHylands]

The thing is, you're not using the IMU on a Bioloid to typically go in a straight line. The one I'm building won't do that, in any case, because that is the one axis that is missing. Version two will add that axis, and produce a full six-axis IMU.

This IMU (the one I'm building) is strictly for balance. It will sense if the robot starts tipping over either sideways or forwards/backwards, and it will also sense large impulses applied to the robot (like getting pushed).

- Jon

[billyzelsnack]

Yeah. I guess HH won't be that useful, but for some reason I think that there must be some use for that data. Not necessarily the exact data, but the concept. The concept of a value representing the difference between input and output sounds pretty useful.