View Full Version : Help a newb get started

09-29-2008, 02:40 PM
Hey guys, great forum you got here. I have been lurking for quite a while and am finally to the point I want to purchase some equipement to start learning and eventually build a rover. Just to give you guys a little background on my experience or lack of, I am a C# developer by trade but have almost no electronics experience. I stumbled across Microsofts Robotics Studio and was fascinated that I could potentially write robotics software in a language I already knew. I have never even met anyone who did robotics programming so I guess it never occured to me that it would be something I could get into.

So anyways, I have decided to build a rover as my first project and trying to decide on what components I need to buy to get started. I have a general idea of what I need but I am having trouble undeerstanding what the pluses and minuses of the different hardware is.

A couple of things I would like to make clear is first of all I would rather buy higher end equipement that I can use on a fairly robust rover down the road and not have to go out in a few months and buy better equipment. Also I don't necessarily need to have API's to program against as I have no problem learning serial port programming but certainly not opposed to using a third party library. And Lastly I would like to first learn to program against these components just hooked up to a pc but eventually have the pc on the rover itself but that is way down the road.

So the 3 options I am looking at so far are...
1)SSC-32 Servo Controller, Sabertooth dual 10A motor driver
2)Serializer WL with Zigbee

I would really like to not worry as much about money as oppsose to what is really the least limiting way to go.

Now I still dont know what motors to use but I would want them to be robust enough to handle a 25-30 pound load. Also I am having trouble figuring out what to buy for the encoder/encoder readers also.

Sorry, I know it is alot of questions but I feel I need to buy some of this stuff to continue learning about it and just dont want to make a costly mistake. Any help would be greatly appreciated.

09-29-2008, 02:52 PM
Welcome to the TRC!

#1 and #2 are not exclusive. Actually - none of what you've listed is exclusive of the other.

The Serializer doesn't have much in the servo control department. The Serializer doesn't have as much in the motor-control department. (It will only drive 4A x 2 and six servos). But it's awesome for sensors and has great libraries - and sometimes, 4A/channel is just enough - it also has external H-Bridge headers for driving beefier motor controllers.

If you went with the larger sabertooth, you could future-proof yourself more.

Phidgets is a broad line, from sensors to controllers and so-on. I tend to avoid it where other options are available - I find that for the more experienced, it's overpriced and there are better individual components, imho.

So, my advice? 1+2 = 3: Serializer, SSC-32, Sabertooth. :)

09-29-2008, 02:59 PM
I would highly recommend the Serializer platform, I've been playing with it a bit lately and must say I am quite impressed.

There is a ServoWizard coming soon from Robotics Connection capable of controlling up to 25 servos, or you could use an SSC-32.

09-29-2008, 03:03 PM
The more I think about it, the more I think I could drive this year's entire competition robot with the Serializer on the robot-end, and an Arduino on the human-end...

09-29-2008, 03:04 PM
first of all welcome...

Now, a rover is a great first project, and if you are looking at the 30 lb point either at present or for future, then might I suggest the parallax motors, potentially an SSC-32 controller. Now at 30 lbs you can probably mount a laptop on your robot for control/brains. A phidget 8/8/8 is a great start for sensor input. Oh...and make some way of lifting your robot off of the ground for testing. Nothing worse than having your 30 lb robot go crazy and destroy things around the house...

Motors (http://www.trossenrobotics.com/store/p/5761-Motor-Mount-Wheel-Kit-with-Position-Controller.aspx)

Servo Controller (http://www.trossenrobotics.com/store/p/3191-SSC-32-Servo-Controller.aspx)

Interface (http://www.trossenrobotics.com/store/p/5341-InterfaceKit-8-8-8.aspx)

Sensors (http://www.trossenrobotics.com/store/p/5438-GP2Y0A02YK-IR-Sensor-Kit-8-60-inches-1-sensor.aspx)

Electronic Speed Controller (http://www.robotmarketplace.com/products/VT-RDFR21.html)


09-29-2008, 03:13 PM
I respectfully disagree on the Phidgets 8/8/8: I'd contend that it's way to slow in the processing department - and doesn't have enough I/O to qualify it for the pricetag. At $25 it'd be worth looking again at...

09-29-2008, 05:19 PM
wow, thanks for all the quick responses. I may just go with the Serializer to start with so I dont overwhelm myself and then once I am comfortable with it get the SSC-32 controller and sabertooth motor controller.

Does anyone have a recommendation for a motor I could run using the Serializer. I think I would run the motors without the H-Bridge controller since I most likely go with the SSC-32/SaberTooth eventually.


09-29-2008, 05:32 PM

These should push a few pound robot around pretty well.

Alas, you're not going to get a 30lb robot going very well (ie. other than dog slow) with 4A...

09-29-2008, 05:47 PM
Good point, I guess to prevent having to buy more powerful motors I guess I better start with the SSC-32/SaberTooth and build the drive train.

Adrenalynn, would you have a recommendation for more powerful motors. I really dont understand anything about the specs on the motors. Thanks for your patience.

09-29-2008, 05:59 PM
No worries!

You're thinking 30lbs over-all?

I think DarkBack's recommendation for the Parallax motors is a good one - but you'll want the larger Sabertooth.

09-29-2008, 06:17 PM
I have the Parallax motor kit and it is awesome Xero, This will be used in one of my next rovers, I am also using the HB25 motor controller from Parallax. 25amp. Also Welcome to TRC.

09-30-2008, 05:13 PM
I have been furiously searching on all the products you guys have suggested including the parallax wheel kit. I am not sure the parallax wheel kit would work for me because I had hoped to put the motor and the encoder in the chassis of the rover to protect it from the elements. With the motor and encoder that close to the wheels I am afraid even in wet grass I could have some problems.

I have decided to go with the SSC-32/SaberTooth 25a and was looking at what kind of encoder to use and after watching the servo/motor controller video on this site I liked the look of the encoder they used, which Alex told me over the phone is probably the us digital e2 encoder. Have any of you guys used this encoder? I also am looking at getting the phidget high speed encoder reader they used in the video so any feedback would be greatly appreciated. Thanks!

09-30-2008, 07:34 PM
Just as a side note: If you're not planning on submerging it, I wouldn't worry too much about the motor used in the parallax. They're designed for use in cars for power seats, and for rear windshield wipers. They're made to take a beating, and the motor itself is well sealed.

If you're planning on submerging it, all bets are off, and we probably need to know that before we speculate on what might drive your load.

09-30-2008, 08:00 PM
Well, I imagined the rover being able to handle all sorts of outdoors environmental conditions by water proofing all the electronics in a pelican case using baffels that are sold specifically for that application. Now, I know nothing practical about what it would take to build something like that so I am probably over reaching what is achivable at my basic skill level. I thought I would start just trying to build a very basic indoor rover and then slowly graduate to increasing levels of outdoor prowess and complexity. Even if I fall short of my goal I am sure I will be infinitely more knowledgable about robotics then I am at this point.

Thanks for all your time answering my questions Adrenalynn.

09-30-2008, 08:45 PM
I think you can certainly seal something to make it environmentally resistant. I think submerging is a heck of a lot tougher than "splash-resistance". Splash resistance, I'd trust the motors that Parallax is using pretty far, but I don't think I'd submerge them. The motor is sectioned from the gearhead with a gasket, but internally I don't know that the shaft penetration is water-proofed.

10-03-2008, 08:00 PM
Hey Xero, are you going to manufacture your own chassis?

10-06-2008, 03:47 PM
BMoscato, I am definetly researching chassis design but I have realized in the last few days that I need to start slow and not try and tackle a chassis that is impervious to the elements for my first project.

I have decided to take the sage like advice of the forum elders and go with the parallax wheel motor kit which will enable me to get something working quickly. I am still hopeful though that at some point I will be able to build a rover like what I have in mind. Just won't be my first project.

I think for this first project I will try something simple like a lexan base. I am spending lots of time in the mechanics / construction sub forum and getting lots of good ideas.

10-06-2008, 04:30 PM
Just a thought, check out the tramp project (http://forums.trossenrobotics.com/showthread.php?t=2173&highlight=tramp). It basically uses the set up you are interested in, and you can get up and running pretty quickly. As for water proofing, unless you plan on completely submerging your robot you should be find for pretty much anything except salt water if you just sheild the electronics. Also, just because your not doing something right away doesn't mean it isn't going to happen at some point.


10-07-2008, 10:24 AM
DarkBack2, thanks for the encouraging words and the heads up on that thread. That really does give me alot of ideas for building something relatively quick.

10-07-2008, 12:45 PM
I use a lot of Lexan or poly carbonate sheet and this works fine for me for a robot base, Whatever you choose you will have fun building it, and good choice on the Parallax motor kit, You won't be disappointed Xero.

10-07-2008, 01:45 PM
Another question for you guys. I am wondering if I can run a sabertooth 25a motor controller from the serializer or do I need to get a scc32 or the servo wizard which should be coming out soon?

10-07-2008, 01:47 PM
You can run it from the Serializer as long as you can spare two of the limited servo channels on it. Just another PWM device.

10-07-2008, 02:05 PM
Thats good news. It will only be for a little while to get up and running. I will eventually either buy the new servo wizard or an ssc32 but want to wait till other more experienced people have a chance to test out the servo wizard and see how it compares to the ssc32. Thanks

10-07-2008, 02:28 PM
I'm thinking I can run this year's competition 'bot from the Serializer, with an Arduino or Axon sending the processed controller data to it over an XBee link...

Oh, you know what - there's a snag that effects you too...

Make sure you read page 17 of the Serializer manual carefully: http://www.roboticsconnection.com/multimedia/docs/SerializerWL_UserGuide_v2.1.pdf

I hate crappy documentation that doesn't give *actual* specs.

10-07-2008, 03:35 PM
Can you guys help me intrepit this message I got from robotics connections concerning using the sabertooth 25a and the serializer? I posted the same question on there but they just got back to me. This was his their response to my question....

"...if you want to use it in Servo mode it will work, but the built in PID controls will not. They are designed to use the PWM and dir controls which are not included in this controller."

I really am pretty lost so any help would be appreciated.

10-07-2008, 03:44 PM
Summary: Use the Sabertooth in servo mode and life's good. :)

10-07-2008, 03:49 PM
Sounds good to me :)

10-07-2008, 04:00 PM
It's looking like a 3A regulator and a 1.5A regulator from specsheets I've found online. Make sure you use the jumper on page 17, and split-up the big servos from the smaller ones. And don't try to run any motors from it at the same time. Bonus points for heat-sinks.

10-07-2008, 04:14 PM
Thanks for the advice Adrenalynn.

10-11-2008, 03:14 PM
Hey guys, I am going to pull the trigger and get the parallax wheel/motor kit and the caster wheel and wanted to know is there any hardware I should order at the same time like nuts/bolts to connect to the chassis, so I don't have to pay shipping later.


I am going to be making another order from Trossen later this week or next to get the electronics so if they have better hardware then I can just order from them when I get the electronics. Thanks for your guys help so far. Makes me alot more confident spending this much money knowing your guys opinion.

10-11-2008, 04:30 PM
Nuts, bolts, that kinda stuff is generally the domain of your local home improvement store, unless you get down under #4 which you shouldn't need to in this case.

Worth ordering some servo extension cables whilst you're there - they add almost nothing to shipping cost, and if you don't end up needing them at some point, you're a freak. ;)

10-12-2008, 12:48 PM
My local ACE stopped selling in bulk, so you can only get nuts and bolts in little plastic envelopes with counts less than 10 each (and weird multiples so that you can't get matching numbers of bolts and nuts). I go through machine screws like pretzels so I like Bolt Depot (http://www.boltdepot.com/). Even for a relatively small order the cost of shipping boxes of bolts is a lot less than buying hundreds of tiny packets.

10-12-2008, 01:21 PM
I'd believe that. The local Lowes here still sells bulk.

10-13-2008, 01:46 AM
I just realized I don't know if I will be using metric or standard bolt sizes? I am use too metric just from working on japanese bikes and cars but I am fine with standard also. Which one do you guys use?

10-13-2008, 12:03 PM
I do everything in metric - except nuts-and-bolts. Go figger.

Meta - I hate you. I just spent like $200 at that site. A hundred of everything - woot!

Great price on nylocks which are almost impossible to find in 4-40 everywhere else...

10-14-2008, 10:32 AM
I usually get my stuff from www.mcmaster.com. They have everything you could ever want.

11-06-2008, 10:56 AM
Hey guys, been busy but I have recieved my parallex wheel/motor kit and rear matching caster. I am now looking at creating a inexpensive chassis to begin testing. The reason I am deciding to go with an inexpensive chassis to start with is so I can put my financial resources into my electronics. also I will be using a dell mini pc initially for the brain which will eventually be replaced by a much smaller pc in the future. I don't even think I will bother mounting the pc on the chassis but rather just have the chassis suspended on a platform with the electronics and battery and have the pc next to it.

So anyways I was thinking of just using the aluminum tubing you can buy at lowes for building something to attach to the mounting blocks that came with the parallax kit to clear the motors. Then just use some ply wood as a base which I could play with and modify easily. Once I am further down then road I could invest in building a proper aluminum/lexan chassis but for a while I assume I will just be messing with the software.

what do you guys think? Is there any major downsides to using plywood initially for a base other then being heavy? Could I have grounding issues? Again I am total newb to electronics so don't assume I even know the basics. :)

Again I really appreciate the help.

11-06-2008, 11:04 AM
if i were you i would avoid controlling it with a micro pc to begin with... start with a widely used microcontroller like the atmega(arduino and clones) or a pic and a wooden chassis would be fine if you use 1/4 inch or smaller.:cool:

11-06-2008, 11:29 AM
Now see, I would totally disagree with Bobtheclam here. There's no reason to base an entire robot design on an underpowered, "under-memoried" platform. Why have the torque of those motors if you're not going to put a real brain on the 'bot?

The Arduino or, even better, the Axon make fine data acquisition and preprocessing interfaces to a real computer. But this isn't the 1980's and 8-20mhz is absolutely not the way to move robotics forward...

[And before my bias is examined, I would like to point-out that I've been doing microcontroller and embedded device engineering professionally since the 80's. . .]

I've yet to see the Arduino that can handle stereoscopic vision, or map a point-cloud of a few million plus points in realtime (or at all without hacking a lot of memory on it, and even then you don't have the address space).

Micro-PCs are inexpensive, reliable, consume very little power, and deliver a _tremendous_ amount of processing. One couldn't put 500 Arduino's on a 'bot and touch what you can get from a $300 PC.


You know the most inexpensive bases I've built? Old PC cases. All that nicely formed light-weight metal.

11-06-2008, 11:54 AM
Thanks for the feedback.

Bobtheclam, thats good to know I can work with wood to start with since I just don't have the tools or knowledge to do anything else to start with. As far as not using a pc you have to understand I am already taking a leap to just attempt building a robot at this point in my understanding of robots building. It is really the only way for me to put something together in a reasonable amount of time. Also almost all of my experience with programming and technology has been on a microsoft platform. I know alot of people scoff at this put they pay me way to much money progrmaming on a .net platform to even consider dabling with programming on another platform. I absolutely love the .net progrmming environment but will try to be open to using others in the future.

Adrenalynn, am I making too big a deal of working with lexan for a base or do you think my plan is ok?

11-06-2008, 11:55 AM
"You know the most inexpensive bases I've built? Old PC cases. All that nicely formed light-weight metal."

Sorry, missed your last comment thinking it was part of your sig. I think that may be worth me looking around for an old case or modifying my current dell mini pc. Thanks for the advice.

11-06-2008, 12:28 PM
Being a .net programmer myself xero, I can certainly understand. I've been in robotics for several years now, and I still have yet to build a non pc-based robot. Don't get me wrong, I've been wanting to learn more about microcontrollers and programming in C. I just get too side tracked by all the incredible things (some of which Jodie had already mentioned) that only make sense to do with a pc-based robotics solution (vision, navigation, speech, networking, etc.).

11-06-2008, 01:00 PM
Sorry, Xero, I should have made it more obvious.

You know, modifying a mini-ITX would be interesting. Basically just motorizing the case. The mounts should bolt-up to it pretty easily, and then the case top would be the platform to build whatever task-based stuff you need on top of it.

11-06-2008, 02:34 PM
this pc I have to start with is actually a micro-atx and I am not actually familier with what mini-ITX cases look like. I actually traded my dell fullsize desktop to a freind for this one because of its size. This case is roughly 11x11 but is pretty heavy. I figure for what I am using it for will work until I can afford to buy a mini-ITX and a solid state hard drive.

11-06-2008, 02:38 PM
A micro atx? Doesn't that need multi-voltage high-amp power, like from an ATX power supply?

11-06-2008, 06:26 PM
I believe so although I am lost when it comes to the terminology. I have been researching on http://www.mp3car.com/ how to run pc's off a 12v battery. Here is what I would use between the that zeus battery trossen sells and the pc. http://www.opussolutions.com/index.php?p=product&id=49. Will that not work?

Edit: Also just for clearification I can always leave the pc plugged into wall with the power supply provided by dell right?

11-06-2008, 09:46 PM
Yup - that Opus should work. Plan on needing lots of battery power.

11-06-2008, 10:57 PM
will the zeus with a trickle charger work ok? Simplicity is my MO.

11-06-2008, 11:44 PM
If you don't put too much load on the PC, keep the weight down on the platform, and don't put the motors under a lot of load, you should get twenty or thirty minutes out of it...

11-07-2008, 02:39 PM
You know the more I think about it I am not going to power the micro-atx pc by battery to start with anyway. I will be doing the initial testing with the robot on some sort of base with the wheels off the ground so it won't be mobile at first. I will just use the battery to power the motor controller but have the pc plugged into the wall.

Once I switch to a mini-itx then I will go ahead and power that pc with the battery. I think. ;)

11-07-2008, 05:34 PM
Just to jump in, I've made some pretty good PC based robots using laptops. Different than a pico ITX in that with a pico you have a motherboard, but still have to add , a way to mount it, a harddrive, usb ports and so on. You then have to find some way to remote interface with it, or plug it into a screen, keyboard and mouse.

Laptops that work reasonably well can be gotten for really cheap...I for a while had 10 running in my classroom each of which was purchased on Ebay for under $50. A couple needed replacement batteries, but even that was only about $50 making it a laptop for under $100. Sure they were older, but at this point older may be close to 1ghz, which puts you in range of a pico ITX.

If size is what your after, I have, and currently use a sony vgn-180ux micro or UMPC. It was $2000 when I got it, but they can be gotten for as little as $600 on ebay. Here you get something small light, and as fast as a pico ITX for only a few hundred more, but it comes with a screen, keyboard, mouse, and even 2 built in webcams and a cellular modem.

Finally, my wife just ordered me a wibrain for my birthday. It's a via based UMPC. Its 7.5 inches long, 3 inches high, and 1.1 inches deep. weighs just over a pound, and has all of the above except for the cellular modem. She payed just over $500 for it including shipping from Australia.

Not sure, you would have to check with 4mem8 and Tyberious, but that puts it in range of what they probably put into mounting a pico ITX on their johnny 5s.

Hope this helps.


11-07-2008, 06:18 PM
Of course, all of that is answered with a $30 case and a free copy of VNC...

I'm not seeing any running 1Ghz laptops for $50 yet - do you know of someplace to find 'em? The 1Ghz laptops I see tend to be up in the $300 neighborhood still on eBay and the used sellers.

11-07-2008, 10:02 PM
Of course, all of that is answered with a $30 case and a free copy of VNC...

I'm not seeing any running 1Ghz laptops for $50 yet - do you know of someplace to find 'em? The 1Ghz laptops I see tend to be up in the $300 neighborhood still on eBay and the used sellers.

Ok...I got a dell latitude d505 running 1.6 ghz for under 100. It took a lot of time and patience, and taking a risk on a computer that was listed as not working...forget what this one needed...but I think it may have been a hard drive problem. So it may be a bit more for someone who doesn't want to take the risk. I've gotten a bunch that were slower...600 mhz or so pretty easily. for students it doesn't really matter that much.


11-07-2008, 10:03 PM
Adrenalynn, do you know roughly how much longer that zeus battery would last with a mini-itx as opposed to the micro-atx? Also I just noticed you can slap a pretty decent size dual core on the mini-itx intel boards. I would assume using a 3 GHz dual core though would probably use alot more juice then a 1.6 GHz atom chip but I really don't know much about the new atom chips.

Also now that I am getting stuff together I think I grossly over estimated the total weight of this robot. I am thinking now it will initially be around 10-15 pounds but hopefully I can get it down to 8-10. I guess it comes down to how muich money I end up wanting to spend on it. I have a feeling this is going to turn into another expensive hobby. :p

11-10-2008, 03:50 PM
Hey guys, I about to put in a order questions about what cabling is needed to make everythinig work. Below is a list of what I am getting.
- zeus 12v battery
- Robotics Connection Serializer WL
- USB Communication Connector
- Sabertooth dual 25A motor driver
- SSC-32 Servo Controller
Already have...
- parallax wheel and motor kit
I am not sure of what cables I need to connect the motor controller to the motors and what cables to use for connecting the battery to the motor controller. I think I understand what I need for everything else but to be sure I included a simple diagram so you guys can look at what I am doing.


11-10-2008, 07:39 PM
The battery to motor controller is just two pieces of fairly heavy gauge wire (speaker wire, zip cord, stranded house wire, etc) raw on one side, with lug connectors on the other (from your automotive supply, Walmart, Lowes/home depot/etc.)

I actually don't know that I know what kind of connectors come on the Parallax motors. Wanna shoot a photo and post it? From the motor controller to the motors on the motor controller side is also just bare wire. 2 pairs of wire like your battery wire above.

Bonus points for picking up a blade fuse holder and some blade fuses whilst you're getting your crimp-on lug connectors. Put the fuse on the positive wire coming from the battery, as close to the battery as you can reasonably get it. Pick up some "quick splices" or wire-nuts while you're at it too. Good for spicing in things like that blade fuse holder.

11-11-2008, 09:23 PM
Adrenalynn, I have attached 2 pictures of the wiring from the parallax motor. It has 2 wires coming from the motor into a plug and then one wire coming out of the plug with a connector.

Also, thanks for the tip on the fuse. I found a nice water proof blade fuse holder online. I assume 10 amps is fine for this battery? Thanks



11-13-2008, 10:48 AM
ok, tehehe. I feel kind of stupid. So those wires from the motor just go to the motor controller and the battery hooks up to the motor controller. I told you guys I am electrically impaired. :p

11-13-2008, 11:22 AM
Sorry I missed your post!

That's correct. Battery goes to the battery terminal, each motor goes to the motor controller. I generally slap mine across a battery first so I can make sure I match-up rotation direction (on unknown motors), but you can always just reverse the wires later (or reverse the control channel). You can find that Molex connector if you want to be all spiffy and stuff, but for space constraints (and price), mine end-up on the floor looking up mournfully at a pair of edge nippers. ;)

11-14-2008, 10:09 PM
Thanks for all the hand holding so far. I am a little nervous about making newb mistakes with electronics as this stuff isn't exactly cheap. I have ordered a ssc-32, serializer, motor controller, battery and a bunch of odds and ends so I am anxiously awaiting there arrival. In the mean time I am going to start looking at getting familier with serial port programming and reading up on the ssc-32 so hopefullly I can hit the ground running.

12-29-2009, 08:01 PM
Hey guys, it has been forever since I have had the chance to work on this project but I have been practically working 2 jobs for the last year so I am just now getting back to it. I ended up using the parallax motor/wheel kit which I mounted to a simple chassis made of 3/4" aluminum tubing and lexan. Currently I plan powering most things from ac wall adaptors except the motor controller but I will be slowly be working on getting it mobile. I have included a simple diagram of the components and how I am planning to hook them up. I would really appreciate any feedback since this is the first time I have ever messed with electronics.

One question I have is how do I actually connect the ssc-32 to the sabertooth 25a? The only picture I have found of connecting the ssc-32 to a motor controller is on lynxmotions site and they show connecting the #14 and #15 channel to 3 pin connectors on the motor controller. Since the Sabertooth 25a doesn't have those 3 pin connectors on it do I just hook up the pulse pin for channel #14 to S1 and then the pulse wire from channel #15 to S2?

Also, do these dipswitch settings look right for running the sabertooth in analog.
1 up
2 down
3 down
4 up
5 up
6 down

Any feedback you guys have would be greatly appreciated. I am very nervous about hooking all this stuff up. Thanks