Deca - son of Glowstrand

After making the Glowstrand, I decided that I wanted to design something that was all mine... and with a big change, Mid Outboard Motors, using some cheaper more available motors. I got the motors from IC Station, but they are available in many stores. They must have the dual output shafts for this design. Deca is very fast, its going to need some excellent sensors and processing, I'm using a Parallax Propeller Quickstart board and a L9110S DC/Stepper Motor Driver Board TBD for motor control. It also has eight 4 x 10 x 4mm ball bearings for the big gears. I used short pieces of filament for pins on all the leg joints, carefully melted over the ends to make them stay put. The frames are held together with four 125mm long pieces of m4 threaded rod, and a bunch of nuts and the 8mm and 11mm spacers. I used nylon nuts mostly. For the big gears, I used two 53mm long pieces of m4 threaded rod as axles, with m4 locking nuts. For the crank pins I used m4 nylon screws. You will need to drill and tap the holes in the gears. You will also need to clean up all the 4mm and 1.8mm holes in each part.

12/11/2015 Added updated Servo Head. Also added an extra battery tray for 1700 2s LiPo to attach to the bottom, so there is more room for components in upper section.

12/20/2015 Added upper tray for processora lower front IR Sensor mount and I made a new servo head for a RadioShack Ultrasonic Range Sensor and a Sharp IR GP2Y0A21YK0F Analog Distance Sensor. Recessed mounting holes for 9g servo horn, also has nice wire path. Also posted here:

12/29/2015 Added Nikia 5110 LCD



Here are some detail shots of the drive system

First test of motors... really fast!
First test of the L9110s motor controller
Fun with Nokia display
Fun with LEDs, and now has some good navigation

 Ankle.stl - Print 8 of these and 8 that are mirrored 

thigh3D.stl - Print 8 of these and 8 that are mirrored

 Each half (mirrored pairs) to be pinned together with short pieces of filament and glued with super glue
 dogbone3.stl- Print 8 of these and 8 that are mirrored
  Use small allen wrenches in the pivot holes to align and glue these halves together
 LongRod3D.stl - Print 8 of these
 MidRod3d_x.stl - Print 8 of these
 ShortRod3d.stl - Print 8 of these
 Pinion4.2-1.stl - Print 4 of these
 Spur Gear4.2-1.stl - Print 4 of these
 Shoe.stl - Print 8 of these
 OuterFrame.stl - Print 2 of these and 2 that are mirrored
 bodySide.stl - Print 1 of these and 1 mirrored
 bodyTop.stl - Print 1 of these
 11x4mmSpacer.stl - Print 6 of these
 8mmSpacer.stl - Print 8 of these
 DecaServoHeadv3.stl - Print 1
 DecaServoHeadBackv4z.stl -  Print 1
BatteryTray - Optional - super glue to bottom for more room in upper compartment
BoardMount.stl - Upper board mount
 All the inner pivot points are 1.8mm will need to be reamed out with a 1.8mm drillbit and then when assembled use short pieces of 1.75mm filament as pins, carefully melt the ends to make them stay put.
 All the 4mm pivot pints will also need to be reamed out with a 4mm drillbit.
 I used a lot of nylon nuts and some metal and locknuts.


Submitted by JeffRo on Sun, 2015-12-06 07:05

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Very nicely done, Hard to believe that it is moving that fast. Great job Roxanna.

Submitted by fhareide on Sun, 2015-12-06 08:22

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As usual your builds are amazing! Such an eye for detail! Looking forward to the rest of it. I don't want to share mine now. haha. Need to make something crazy cool to top this one.. :)

Submitted by Roxanna77 on Sun, 2015-12-06 12:01

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Your help and inspiration made it happen! Never knew what a Strandbeest was until you made the Sphero Strandbeest, now I appear to be hooked!

Submitted by Protowrxs on Sun, 2015-12-06 10:34

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That looks and move wonderfully. I like the wide legs and outboard motors. Download print files! :-)

Looking forward to the sensors and control.

Edit: Forgot to say that is great designing with that complex setup.

Submitted by Roxanna77 on Sun, 2015-12-06 11:59

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It's been a fun and sometimes frustrating build. Thanks to help from Fredrik on design tools it has turned out very awesome.

Programming is going to be a challenge with all the speed this thing has.

Once I get the Deca style servo head printed and mountd, I'll post this on Thingiverse

Submitted by Roxanna77 on Fri, 2015-12-11 10:18

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OK, looks like I'm drawing too much current? One channel has let the smoke out after only a few minutes of bench testing. With the remaining channel my ampmeter is showing a max draw of .23 amps, but the chip is kinda hot. So, the L9110 motor driver is good, but not for these motors and current flow. They claim 800mah, but I'll be using something else I guess.



1. Low static current work;
2. Wide range of power supply: 2.5V to 12V.
3. Each channel has a continuous output current 800 ma ability;
4. The lower saturation voltage;
5. TTL/CMOS compatible output level, can be connected directly to the CPU
6. Output with clamping diodes, apply to the perceptual load;
7. Control and drive integration with IC;
8. Have the pin high voltage protection function;
9. Working temperature: 0℃ to 80℃
10. Module can drive two DC motor or one 4-wire-2-phase stepper motors 
11. Onboard two L9110S motor drive control chips

Submitted by fhareide on Fri, 2015-12-11 11:35

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Oh no! Maybe I should be careful with the ones I have as well? 

Submitted by Roxanna77 on Fri, 2015-12-11 16:25

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I found our great friend Bajdi has a nice tutorial on these boards (

I did see that one of the comments Francios added had this:
"I tried these DC motor controller but if you want to control your DC motors with a PWM signal, you should remove the Caps which are connected to the output (the two caps close to the “Motor A” “Motor B” writings on the board)
I fried two of these things by driving them with a 500 Hz PWM signal at 7.4V and I think this is caused by the capacitors on the output."

And I was doing PWM at 800 HZ @ 8.3 volts, maybe that is problem? 

Although, I ran each motor after the smoke came out with the single working channel for about 15 minute each, and saw no more smoke episodes, so maybe just a bad chip?  

I really want to be able to use these as they only take four inputs and the price is fantastic. I will try again.

Submitted by Roxanna77 on Sun, 2015-12-13 19:04

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Maybe a better design? New one on left.

Submitted by Roxanna77 on Wed, 2015-12-16 22:59

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No issues after much testing. I really like this motor driver board as it only requires 4 pins. 

Submitted by fhareide on Mon, 2015-12-21 06:42

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He really looks good! Amazing work, Rox! Looking forward to the first navigation video! :)

Submitted by JeffRo on Mon, 2016-01-11 18:33

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Just watched the video with the screen and that is awesome great job there.

On the other video where his head is moving from right to left is this done to make sure no objects are in the path?


Submitted by Roxanna77 on Mon, 2016-01-11 19:41

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Yes, it is moving to check for obstacles and to do path planning. Right now its doing just a two step scan, I'll at some point make it a bit more granular

Submitted by viswesh on Sun, 2016-01-17 10:24

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it's a nice robot project. nice walking mechanism

Submitted by maelh on Sat, 2016-01-23 17:09

Very nice robot. Fits the season: it looks like it's made of iced snow.

I noticed you have some power connector on your PCB that receives the plug from your battery pack. I had trouble finding such PCB mountable connectors. Where did you find it? And how did you make sure it is stable enough and does not rip off? My connectors (a different shape but also big) seem to get stuck pretty tightly.

Would you have any details on this self made PCB in general? I would be interested, as to compare and get clues on what I might have missed in mine.

Submitted by Roxanna77 on Sat, 2016-01-23 19:48

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The connecttor is a x60 that I cut open and then put a nylon screw through it to hold it to the board, and some super glue. On the board I added a LiPo battery protection circuit so I don't kill any more battery packs.

I'll get some detail shots and a circuit diagram up soon