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Microcan 6 months ago.
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No comments yet, but I made this little robot last week. Because I ran out of filament I printed the robot with lightweight woody filament.
@microcan I moved this to here because it is so cool 🙂
For official support please visit www.cel-robox.com/support/ and create a ticketThanks Pete. I made it as inspiration for students embedded systems. I saw a youtube video where somebody build a small robot with popsicle sticks, double sided tape and a few servos. I thought that a 3D print would make it resemble more like a real industrial robotarm.
I like it. Kind of a do nothing machine. I can see this on a desk at work running continuous on a raspberry pie. Are you going to put it on Thingiverse.
Yes I will publish it. I used 4 low cost SG90 servos (nylon gears) in this version. I ordered some MG90 servos (metal gears) but these are still somewhere in transit from China. I like to compare these servos and probably make some little changes to the model so both servos will fit.
Meanwhile I tested if spray paint (Hammerrite) would make the model better. I have to improve may spray painting skill, I was a little impatient and used to thick coats. Did not sand the prints 0.3 mm layers. I looking for a company that sells spray filler. I have seen some very good result using spray filler and sanding on the internet.
Right side is nGEN White and right side is Woody.
I got the metal gear servos from China. The gray/brown servo with photo is the MG90S metal gear servos and the blue servo is the SG90 with nylon gears.
Unfortunately the servos are quite different. It turn out that almost every dimension of the servo is different. It is not as simple as tweaking some dimensions so I am remaking the same design for the MG90S servo.
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Any particular reason you wanted metal gear servos? Did nylon gears slip? I found that at the same form factor servos with metal gear are usually more sloppy, slower, weaker… They usually do not slip of course… but in some applications that’s even desirable for servo gear to get broken rather than something else… (probably not in your case)
I try metal gear servos just to test the difference. I did a complete dissection. I discovered that some full metal gear servos still use a nylon for the first gear. I did not do a full comparison yet for these servos. But the lower cost nylon servos seem to have the best cards.
@microcan Yup. That the best reason for it. Shame they didn’t make all those tiny servos same size. I bet that SG90 and HXT900 (in both ‘9’ stands for 9g servo - which, again, very few use as denomination) are slightly different, too.
BTW How are you driving servos? I am planning to make PiZero into USB stick that will do exactly that: expose GPIOs to whatever program on the computer. I used Raspberry Pis extensively with servos in a few projects. Latest is here: https://gccpiwars.wordpress.com/2017/03/21/the-making-of-the-rovers/
My day dreaming goes along the lines making PiZero as a ‘ethernet adapter’ (along being powered through USB) and appear on network with some rest services exposing GPIOs, i2c, SPI, serial and some other interfaces.
Another is to finally use 24 similar servos like yours (no idea what brand - the cheapest) for little spider. But there I would rather have feedback what current they are using (at least by each leg’s 3 servos) and I am gearing (for two years now) to make it using AT mega - two boards each to drive 16 servos and talk on i2c to whatever is going to be main controller (RPi probably again).
BTW Did you consider using web cam and open CV with your setup? That would be cool it to have feedback (visual feedback) and know where the ball is! 😀
@click thumbs up for the rover.
Controlling servos is easy with almost every microcontroller, if you get the pulse width modulation correct. I have done this in the past with 50 cent microcontrollers. For this demo I used a PSoC (Programmable System on Chip) and implemented an optimised servo control in hardware. This leaves more processing time for firmware when the number of servos increases. The cost of the PSoC prototype board is lower than the average I2C servo board.
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