So I found the Hexbug VEX Strandbeast on sale at our local science museum, and I picked it up.
Here some first impressions, and some thoughts. Let me know what you think.
In general, this is a big and ambitious build. The printed instructions in the box had a few errors and omissions, but it was easy enough to figure out how things should work. In particular there were some issues on setting up the legs so that the walk cycle is correct. I note that in the downloadable instructions these issues have been fixed, the online version is much clearer!
I had some issues getting the robot to work in autonomous mode. The way the brain is programmed is by setting DIP switches on the brain that define the relation between sensor input and the motors. It would be useful if these switches were set to a sensible default, or if there were a few examples of settings that do something useful (eg. avoid obstacles, stop before crashing, etc).
I think there should be a note in the instructions about avoiding friction. If you snug the rubber stoppers on the shafts right against the plates, they add a LOT of friction, enough to prevent the robot from moving. I also found that it was critical to align all the small gears and all the big gears correctly, otherwise it was possible to slightly twist a shaft and have the big gear “off by one”, which also created a lot of resistance.
A final issue is that the robot is big & heavy, and this is all powered off 3x AA batteries. So the robot is a little slower, and also burns through batteries quite quickly. This is made worse by the fact that the battery covered is buried deep within the robot when assembled, and not easily accessible. In the short term, I used VEX IQ parts to rebuild the robot in a way that the batteries were much more accessible.
I am intrigued by the possibility of swapping in VEX IQ parts for the motors/sensors/brain, this would dramatically improve performance I think. I note that the smaller motors that come with the kit are mounted on standoffs, so the VEX IQ motors actually fit perfectly (without standoffs). There seems to be plenty of room for the VEX IQ brain too.
I am also interested in using some of the kit specific parts in conjunction with other VEX builds. For example, the “shoulder blades” in the Strandbeast kit don’t serve any functional purpose, so they could be replaced with beams, and then used as a scoop/blade in another build.