Sloth Robot

erco

Senior Member
#3
I'm sure I'll be the first, whenever I can get around to it.

Yes, please take that as an arrogant challenge and do it yourself and prove me wrong! I love the taste of crow! :)
 

stan74

Senior Member
#6
Nice erco. That's £30 with discount code. Hmmm. srfo4 and 4 sg90 is £15 so £15 for the acrylic.
Safe except the sg90 on my robot for us radar has been changed twice. Don't know why they failed and that's just a srf04 left and right.
Coding would be hard unless there's source..in c++
 
#11
Thanks, that's great, steliosm!

I just saw that you are in Athens, what a great city! I ran the marathon there in 1999. I only know one other Greek roboticist, Nikos G. A very smart and enthusiastic teacher, you can find him at https://forums.parallax.com/profile/NikosG

And do you know the guys at Muse Robotics? http://www.muserobotics.com/contact.html
Actually, I don't know any of those guys. I'm more into "connected objects" rather than robots.
Sadly, there used to be a Greek robotics forum (grobot.gr) but it's now long gone. I hope now that robotics is a part of the curriculum to actually see this science field to take off in Greece.
 

erco

Senior Member
#13
Lovely, Stanley! Yes, those 12 servos will suck a lot of current. Even more under load! Use good batteries and big fat power wires.
 

stan74

Senior Member
#14
18 servos erco. the pca9685 board don't like not enough power for servos although it has own 5V supply and the servo supply is totally independent.
There's a set all channel command and I use scale..arduino map function but in basic to convert degrees to pulse width. This sets all 18 servos to 90 degrees.....
but with not enough power all servos go to 0 degrees.
My thought is a 8 A bridge rectifier and 7.2V li-ion,4 batterys. The bridge is 2 diodes in series twice so should drop 7.2V to 5V. I've ordered a dc-dc 8A buck converter anyway.
If you nick the init code for these boards they'd work with picaxe.
Also , you can take a wire off the pot in the servo,connect to a-d and get servo position. There's probably a 16 channel a-d i2c chip some where..it seems familiar..I might have some.
I could then teach it to walk. otherwise it's trig or tables.
It needs longer legs so less strain on servos...from first thoughts an tests.
 
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stan74

Senior Member
#16
Yep, a great and worthy experiment. Here's mine, using an 08M2's ADC pin:

That's encourageing. Converting the adc read value back to micro seconds should be easy.
The hardware side of making a walker is...the drill bit snapped and went through my thumb nail...I bought an A8 reprap i3 clone kit for £84 and will print the parts.
 
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