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Forum Member
 
Group: Forum Members
Last Login: Saturday, August 14, 2010 12:06 PM
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Greetings,
I'm very new in the robotics realm but not to electronics. I'm a senior at my university and am working on projects towards my BSEE degree, as well as being a part of the NATCAR competition project and most recently micromouse.
I have done a considerable amount of research into finding the right platform for my "line follower" robot that will be used in my MCU design course. I have considerable MCU programming and hardware experience (compared to academic ideals) and am looking to challenge myself this semester. I chose the Traxster for a number of reasons over the competition. First, how amazing does this guy look?! Very nice design. Secondly, I needed something with differential steering that used something besides the el-cheapo servos that Parallax is providing with BOE-BOTs. This stems from my NATCAR team's goal of using BLDC motors--the Traxster is a compromise between a jerky stepper motor option and a BLDC optical servo configuration (expensive). I have to build all of the drive circuitry (H-bridge, etc.) and I will have to use the standard Atmel 8051 variant for the brains of the line-follower bot. I did not purchase the "serializer" circuit and will have to provide my own quadrature encoder/PID motor control algorithms. With this in mind, I have a number of options.
I enjoy the PIC line of microcontrollers and have a number of variants and boards. One such combo is the dsPIC motor controller family on a demo board. I don't think time will permit but I expect the Traxster II to be with me beyond this one class (hopefully I can expand on it and use it as a research bot, etc., for my senior design project). I think the dsPIC option is overkill for this project and it would be a steep learning curve as my DSP experience is only theoretical. Another option I have for programming the PID and quadrature motor control is a HC12 board that's very fast with tons of memory (I can use the memory to "map" the route which would guarantee me an A+++ in the class). I don't have any issues with interfacing the 8051 routine with those to handle motor control, etc. My concern here is that your "serializer" seems to be a moderatly powerful development platform and I'd like to not bog myself or my processor down performing what seems like a simple task of motor movement (I know I'm going to regret saying that).
That said, I seem to be obsessed with this stuff now (robotics was a field I never thought I would enjoy) and am less afraid of the mechanical interfaces thanks to this terrific development platform.
I am looking forward to learning more on the subject and can't wait for the Traxster to arrive so I can start building it. Please accept my thanks and congratulations for what I think is one of the best platforms available--and for exactly the right price that allowed me to pick one up.
Regards,
--Scott
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Supreme Being
Group: Administrators
Last Login: Monday, October 31, 2011 9:18 PM
Posts: 640,
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| Electronguy, First of all, thank you very much for the compliments!  The Serializer uses a PIC18F452 onboard, and I don't know if you realize it or not, but we have a PID algorithm built into the firmware which reads the quadrature encoder inputs on the Serializer, and controls distance and velocity very accurately. So, you don't have to use a DSPIC. Ringo and I took a TI/DSP course a month or so ago, and if the DSPIC is anything similar (with a DSP + PIC CPU), then you will have a pretty steep learning curve, mostly from the DSP side of things. Of course, it would be very cool and satisfying to get it working. But it would probably be overkill. If you were doing a balancing bot, then the DSPIC *might* be better suited for PID algorithms/Kalman filters, etc. I've built an electronic fuel injection system based on Motorola HC16s, so I like that architecture pretty well. The HC12s are very similar, and fairly fast. The input captures and output compares are nice to use for timing various things, and they're pretty easy to interface. The Serializer is pretty darn powerful, and we've yet to have anybody complain about it's performance. Good luck with your project, and keep us posted. You might also want to post it in the 'Projects' section of the forum when you get it up and running. Best Regards!
Jason Summerour
President,
Summerour Robotics Corporation
www.roboticsconnection.com
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Forum Member
Group: Forum Members
Last Login: Saturday, August 14, 2010 12:06 PM
Posts: 44,
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Thanks for the clarification. I think I'll end up ordering a serializer as soon as I have some more $$$, as long as I can interface it with the 8051 (it's a requirement to use the 8051, but I can use the serializer to perform the motor functions). Otherwise, I'll have to write my own routines, but that should help out when I translate the code to the NATCAR and Micromouse projects.
Shucks, the price is right, too, for the serializer board--I really wasn't sure about the .NET programming, though, so I didn't get it. I looked briefly at the MSDN-style documentation and it looks uber cool. I'll try to find the formal "Serializer" document so that I can look at interfacing that particular board with my not-as-intelligent-as-my-PC-based control system
I see my 'bot has shipped. I'm confident that I will enjoy a long standing relationship with Robotics Connection (and subsequently you'll be getting a significant portion of my allowance). It's worth it.
Darn luck to me I spent hours yesterday looking for suitable discrete components to build an H-bridge, and I spent about 1/3 the cost of a serializer board already just on the parts. Hrmmm.
Do you know anything about the AOP607? It's an 8-pin complementary trenchFET that's rated at 60V and 4.7A/3.4A (N/P) with nominal RDSon values of 0.056 ohms and 0.105 ohms, respectively. The repetitive pulse current is listed at 20A. I've never heard of this company before and it seems strange that they came up with such an exceptional P-FET over and above the major competitors. Still, I ordered 40 of the half bridges 'cause they look pretty useful. Other options are the Infineon TLE5205-2 and BTS7810K--maybe an SGS-Thompson L6205.
Well, it's a good learning experience...I appreciate your feedback and will try to get plenty of rest before all the parts and pieces start to arrive 
Best,
--Scott
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Forum Member
Group: Forum Members
Last Login: Saturday, August 14, 2010 12:06 PM
Posts: 44,
Visits: 70
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Printed and read the Serializer docs. Slick. Just placed an order...
OT: I looked for the "Customer Projects" forum and found a link burried in one of the top-level forums but didn't see any activity there. Is it like yet?
I'll check the Serializer forum for questions/FAQs before I start asking...
Thanks again,
--Scott
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Supreme Being
Group: Administrators
Last Login: Monday, October 31, 2011 9:18 PM
Posts: 640,
Visits: 819
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Yeah, people don't really realize what a deal the Serializer is until they start buying all the parts to make up what's included in the Serializer.  The Serializer saves you time and money for sure... I guess we could do a better job of advertising it, but we're engineers, not marketing people, and we don't have a huge marketing budget.  I've never used the AOP607 before. Best Regards!
Jason Summerour
President,
Summerour Robotics Corporation
www.roboticsconnection.com
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