Hi all,
I am presently bidding on a Mattrack modified BOEBOT that is equipped with the stock Parallax Futaba Standard Servos.
Is it possible to modify the biggest HiTec Standard Servo (HS-645) for continuous operation, per the Parallax Instructions, to replace the stock BOEBOT Futaba Servos?
Regards,
TCIII
Sure but it may not be too much of an advantage.
Hi Spacejunk,
I don’t expect it to go faster with the higher torque servo, just want to have a little extra margin of performance in the servo itself since the Mattracks are a much bigger load than the stock wheels.
Regards,
TCIII
Hi all,
Anyone here had any experience with the GWS S06 Continuous Rotation Servo?
With GWS servos in general?
Regards,
TCIII
It was a number of years ago, and the servo models, materials, specs, etc. have no doubt changed at least a little bit, but I used two pair of GWS servos (modified for full-rotation) in a couple of simple differential drive bots for an experiment.
They worked, just as you would expect any standard servos to work, but there was a lot more running noise than I would have expected from any standard servos, even prior to opening them up for the first time. The guy at the hobby shop even warned me, “Now, you’ll notice that these servos are a bit louder than most”.
Even after cleaning up the geartrain and re-lubricating everything, they were still surprisingly loud. The bots ended up being called Toothgrinder and Toothgnasher, because even though there was nothing physically wrong with the servos, and everything meshed properly, all of them constantly sounded like there was something terribly wrong with their geartrains.
As I mentioned before, this was some time ago, and they (hopefully) may have addressed this issue since then. You may want to get one first, play with it, and then decide if you want more of them.
Seamus,
Thanks for the input. Much appreciated.
The modified GWS S06 servos have about twice the torque of the standard Parallazx CRS servos and might be better at turning the Mattracks.
A higher noise level, if it has not been improved, will not be much of problem in this application.
Apparently these are the same servos used by Rogue Robotics Base Kit.
Oh well, we will see.
Regards,
TCIII
Hey TCIII,
If you do acquire this modified Boebot, could you please post some pictures and describe how it works? I have a set of Mattracks myself and would like to build a bot of my own. I was planning on using a couple of these modified servos with a dedicated motor controller.
Link
Hi Maniac05,
You can see the modified BOEBOT here.
Unlike other Mattrack modified BOEBOTS that have been for sale on eBay, this modification does not rely on the servo shaft to provide a mounting point for the Mattrack. Therefore each Mattrack on the BOEBOT is independent of the the other and is free to pivot around the servo shaft.
You can contact the seller/designer on the Parallax Robotics Forum. He goes by the name of T0m. He is the originator of the “Boe Vision” thread: forums.parallax.com/forums/defau … 0&m=181523
The GWS S05 modified standard servo has about the same torque as a stand servo and will require, as you have stated, a separate motor control which can add around $50 or so (Sabertooth 2X5 or equiv). The GWS S06CRS standard servo, which is around the same price, has around 100 oz-in of torque which is about double a normal standard servo and can be controlled from a multifunctional board such as the Blue Bell Design Co-Processor.
I will say that the GWS S05 modified standard servo is an interesting concept that I will keep in mind.
Edit: When I got home this afternoon I found that the Mattrack modified BOEBOT had arrived via the USPS. It only took two days for it to come from NY.
The quality of the workmanship on the Mattrack modified hardware is excellent and I would recommending bidding on any additional Mattrack modified BOEBOTs that T0m may put on eBay.
Regards,
TCIII
I agree, that Boe Bot looks excellent. Thanks for the pictures aswell.
About the S05’s, I’ve never had very good luck with continuous rotation servos, so I’m sticking to dedicated motors and controllers for now. I haven’t tried the ones that Lynxmotion sells, but all that I have used have destroyed themselves by grinding gears and overheating. The same place that I bought my S05’s from also sells a compact motor driver that fits in the servo case itself. I’ve used those controllers combined with the S05’s in the past to great effect.
Hi Maniac05,
Jim has warned that the GW Standard Servo is bigger than the Futaba and Hitec Standard Servos.
From looking at the dimensions of the GW Standard Servo, it looks like the length and width of their servo is the same as the Futaba/Hitec standard servo it is just that the depth of the GW Standard Servo is slightly deeper than that of the Futaba/Hitec standard servo.
Is this assumption correct?
If it is, then the GW Standard Servo should fit in the Futaba/Hitec mounting outline. I have plenty of depth available, so the GW Standard Servo being somewhat deeper will not be a problem.
Regards,
TCIII
I would go with hitec digital servos and modify them for continuos rotation. Digital servos will be much easier to control.
Hi spacejunk,
Thanks for the suggestion, but I am trying to do this project on a budget and the GW S05 modified servos are around $15 each plus shipping. Also, I do not need real fine control of the speed of the servos. I am actually looking for the kind of beefy servo that the GW S05 is with around 100 oz-in of torque.
Regards,
TCIII
A digital servo dosen’t need it’s pulses updated constantly though.
Hi spacejunk,
I am using a Blue Bell Design Co-processor with my ABB that relieves the microcontroller from having to control the servos directly. All I have to do is send the Co-Processor a servo pulse width value and it does the rest.
Regards,
TCIII
The S05’s are actually slightly wider and longer than standard servo cases-- not enough to make them unusable I think. They are, however, definitely taller than standard servos. They’ll fit in the SES brackets but only barely. Hope this helps.
Hi Maniac05,
Thanks for the response. Much appreciated.
After measuring a stock Futaba Standard Servo, it looks like the GW Standard Servo is slightly deeper as you have said, but should definitely fit a Standard Servo O & M mounting pattern.
Regards,
TCIII
GW Standard Servo
I was wondering if GW servo… are they noisy…compare to futaba…?
thank
Hey guys,
I have a Mattracked Boe bot with the standard parallax servo,s and since
the tracks gear it down to 1/3 normal speed it has plenty of power(it,ll climb the wall and sit on its tail and drag shoes around with a gripper) my problem is speed ,and the towerpros on ebay will probly fit but the horn maybe diff ,i would keep it as is for the moment then later go for gearhead motors ,what kinda electronics and sensors u gonna put on it
heres my babyhttp://img407.imageshack.us/img407/3715/dscf0115um9.jpg
Thats Humungous hecka-cool! 
I like espcially like the nightvision camera 8)
Hi cbradsmith,
Nice adaptation of the Mattracks to the BOEBOT!
Did you do the adaptation yourself?
I got my Mattrack equipped BOEBOT off of eBay from T0m who is very active on the Parallax Robotics forum.
T0m is a very accomplished machinist and you can view his work here: forums.parallax.com/forums/default.aspx?f=10&m=181523
I have a Lynxmotion 6 volt/2800mA battery sitting under the BOE, which is actually on top of a Blue Bell Design Co-Processor, for extended running time.
I have purchased two of the GW Servo S05 CRS servos to replace the stock Parallax Futaba servos. The GW Servo S05 CRS servos have around double the torque of the Futabas.
I considered using the dc motor only version of the GW Servo S05 servo, but it only has the same torque of the Parallax Standard Servo. Since speed is not an issue with this BOEBOT and robustness is, the 50 rpm S05 servos will suffice. Besides, I do not need a motor speed controller and can use the Blue Bell Co-processor to handle the servos without burdening the BOE Stamp.
I won a Radio Shack Hummer, complete with four Mattracks, on eBay to be sure that I would not lack for replacements.
I plan to use the Mattrack BOEBOT for backyard surviellance. It will periodically run an autonomous backyard course until it needs manual guidance. I have A7 Engineering Bluetooth transreceivers so I can communicate with the BOEBOT from my home PC.
The BOEBOT is also equipped with a 2.4 GHz wireless camera on a pan and tilt mount that came with the BOEBOT. The P&T is okay, but not nearly as robust as the Lynxmotion version.
I also have a 4WD1 with a Lynxmotion P&T and it is presently being controlled by a Lynxmotion PS2 wireless controller for wheeled vehicle experimental purposes for backyard surveillance.
My main going is get one of Jim’s 6WD Rovers, when they become available, as I feel that the 6WD Rover will be the most robust design for backyard surveillance and defense.
Regards,
TCIII
