Controller question

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81

For board soldering you’re after two things: low wattage, and a small tip. At work we pretty much only use Weller irons. I’ve got a non-Weller at home, and like it a lot, too. (I think that company is out of business, though, and I can’t remember the name off the top of my head.) Here’s a discussion on various soldering irons on Make:

makezine.com/blog/archive/20 … ing_i.html

A couple of points get mentioned in that article that I’ll repeat here: Keep your tip clean! I use a wet sponge, which is pretty universal. Someone on that thread mentioned a brass shavings tip cleaner. I can see that would work well, but I haven’t felt the need to go that route.

When shopping for a new iron, get the best one you can afford. I’ve had mine for over fifteen years. It’s not one of those tools that tends to wear out (unless the heating element goes.) Get a fine tip. Get low power, or better yet a temperature controlled iron. Get one from a company that will be around when you need to replace the heating element or the handpiece. And by all means get good, fine solder for doing board soldering. The thick stuff that’s sold at hardware stores is ok for plumbing, terrible for board soldering.

Congratulations on your project. Great to see stuff move like it’s supposed to.

Tom

82

Tom is absolutely correct about spending money up front on a good iron! For years I was terrible at soldering, then I found out that I wasn’t really all that bad, I was just using terrible soldering irons! Especially when you’re just starting out, you really need a good iron to get really good at soldering, and good irons usually cost good money!

Adjustable temperature is a big help, and keeping your tip sponge-cleaned and coated with solder helps a lot! I’m partial to a very thin silver-bearing solder from Radio Shack. It flows and coats better than any rosin solder I’ve ever used, and it comes in very very thin strands, so its easy to control how much solder you apply. As a rule of thumb I look for things that call themselves a “soldering stations” rather than just a “soldering iron,” and a really nice temperature controlled soldering station that you can use for the rest of your life is going to run you $80-$100 at least. At work we use mostly Weller and Hakko brand irons, but there are plenty of good brands out there.

My personal favorite iron is the Weller WES51:

It can be had for about $100, and it takes a variety of tips, including this one little flat-tip that I use for almost everything!

If you want a medium-okay iron for very very cheap, you might consider the Velleman VTSS5U

It can be had for ~$20, and has a single kind of tip which you can replace for a dollar or two. I wouldn’t want to try soldering surface-mount components with it, but its good enough for header pins and wires.

Glad you got your servos moving, let us know how you are progressing!

-Adam

83

A good soldering iron is definitely crucial, but I disagree with the “spend all you can” approach. I was disappointed by a $500 Weller unit, and my favorite soldering stations are the cheap Chinese ones from MPJA (http://www.mpja.com/prodinfo.asp?number=15845+TL for general stuff, http://www.mpja.com/prodinfo.asp?number=15141+TL for SMT stuff) and other sources. Adjustable temperature and digital readout for under $50! (Plus how useful is a USB port on your soldering iron if it doesn’t solder that well?)

So, I think the brand and individual model really matter more than price, so if possible, try one out before buying one, or at least get one that someone specifically recommends.

- Jan

84

Good info! Thanks, Jan. The one I have at home isn’t adjustable, aside from a high-temp low-temp switch, so that’s seriously tempting.

But I have to ask… errr… Which Weller had a USB port on it? Was it for data logging on temp or something? I’ve come up with some seriously goofy ideas for sticking micros into something but that one has me scratching my head.

Tom.

85

I have a soldering iron looking pretty alike as the ones you have reccomended, i dont really know what type it is (its not written on it and i dont have the package anymore) It’s basicly just a soldering iron and spiral tingy to put it in. So i was wondering, what is the advanteges of having possibility to change the degrees?

86

I didn’t look into what all it was for. Among other things, I think the idea is that you can set up various settings that assemblers can’t mess with, giving you more process control.

http://www.cooperhandtools.com/PDFs/550517_WD_Series.pdf

- Jan

87

From the looks of it the USB port can control its temp and do data-logging. ISO certification is what they’re aiming it for, so my guess is you’re right on the money, Jan.

Mmmmm, the other ones you posted have a lot more appeal. My shop isn’t ISO9001 certified. (Cripes, my shop at home is an OSHA disaster area.)

Tom

88

The main advantage of temperature control is being able to turn the temperature down low, but not too low, just a little more than enough to melt your solder immediately on contact. I usually stick around 550F-600F. I find that single temperature soldering irons are usually either way too hot (which will damage electronics and melt wire insulation) or not hot enough, which makes it difficult for the solder to really soak in (leading to big chunks of bad solder joints, like I think you were talking about).

Irons with temperature feedback are nice too, because you can keep a very small tip at the right temperature, without it getting cold as you work with it.

If you haven’t soldered before, you might want to get a piece of prototyping board (with metal plated through holes) and some bargain bin components, and practice soldering a bit, without fear of messing anything up.

-Adam

89

Well, they think unmarked bottles of water and high-quality extension cords plugged in for more than four hours make for a disaster area, so it’s not saying much.

- Jan

90

When the window where i can control the servos with the keyboard appears. Is there a way to make the servos change its position further then just 1 degree? Anything i can change in the code?

91

Are you still using some form the code I posted?
(If not, remind me what code you’re using)

If so, you can change the step variable in the code, which controls how much a servo moves in response to a single key press:

To double how much a servo moves, set step=100, etc…

How’s your project going?

-Adam

92

Its going just fine :wink:. Me and a clann m8 just finished it up for a school project tomorrow. We met some problems but handled them perfectly =). Its looking kinda cool 2. I dident get the robot working connected to my wireless computer, so we captured it on tape and made a powerpoint of it. Even tough we will bring it to school tomorrow, it wont be able to move. Maybe now i’ll try experimenting with the code a little, i found that to risky to do after just having a working time on 2 days. Hope to stay in touch at the forum, i might send u some pictures of the masterpiece xD CyA

93

Great, I’m looking forward to seeing the pictures!

-Adam

94

[quote=“nexisnet”]Great, I’m looking forward to seeing the pictures!

-Adam[/quote]

I just posted a reply but dunno where it went :S

Anyway, heres the pictures of the robot i made (on my own website) i guess u will be able to find the pictures yourself :wink:

http://www.rson.no

You know where i can buy a microcontroller that can control both motors and servos at the same time, as well as having a section to input a RC reciever (im making it RC) - You know of any cheap packages of RC transmitter and reciever?

Thnx

95

I would like to summ up some over the last posts, to get the information straight:

This is a microcontroller: https://www.pololu.com/catalog/product/215
A microcontroller is like a computer on a robot. It uses the information/codes gathered from the computer to control the robot, knowing how to handle different situations, like what to do if it meets a wall if it has a sensor built onto the robot. This can control both (a few) servos, and sensors and stuff.

A servo controller: Like the Micro Serial Servo Controller
Is a circuit card, controlling servos (ONLY servos) giving the servos electrical pulses all controled by the codes sent over USB cable to the servo controller.

A USB to Serial Adapter:
Is needed for both the microcontrollers and the servo controllers to:

-For the microcontrollers it is needed to send the code from the computer to the microcontroller so it can be stored the the micocontroller and run there as many times as you want without having to be plugged into the computer at all time. If you want to change the code, simply plug it back in and add what you want

-For the servo controller, to send the code directly over USB cable from the computer to the servo controller, running the code ONE time at the servo controller before it needs to be sent again for the servos to do the code one more time. No sensors or anything else then Servos/motors can be added to this servo controller?

Sensors: Like the https://www.pololu.com/catalog/product/136

Can be added to microcontrollers to to different tasks, like obstacle avoidance. But for theese features to work, it needs to be coded in the code that will be sent from the computer to the microcontroller.

Codes:

An example on a code language is C/C+. Codes is needed for the features added on the controller to work.

If you have time to check theese facts i picked up from this topic and correct me it would be great :wink:

On the other forum i mentioned, the admin made this micrcontroller: http://www.societyofrobots.com/axon/ Is this all features needed built-in? All you need is to add sensors/sevos and all of that?..Thnx

96

For the most part you’re correct, but there are a couple of things I should add.

In general, Microcontrollers need programmers (like this one for example) to download compiled programs to them. Some microcontroller boards come pre-programmed with a particular type of program called a bootloader, which lets you download compiled code to the microcontroller over just a serial connection, so you don’t need to buy your own programmer. The Axon microcontroller board you linked to comes pre-programmed with a bootloader, as do the [arduino.cc/]Arduino[/url] line of AVR microcontroller boards. The Pololu Orangutan line of microcontroller boards do not currently come pre-programmed with bootloaders.

As you noted, you can’t just connect a computer’s RS-232 serial port directly to a microcontroller, you’ll need to use either a USB to TTL-level serial adapter, or an RS-232 serial port to TTL-level serial adapter.

All of the Pololu servo controllers can be commanded directly from a microcontroller, without a computer. The USB servo controller can be plugged directly into a computer USB port, and all of the serial servo controllers can be connected directly to RS-232 computer serial ports without any extra adapters. You do need to be careful to connect the controllers properly, as the RS-232 signal voltages can damage the servo controller if they are applied to the wrong pins.

A separate servo controller is very nice if you need something easy to use or to control a lot of servos, but you can also program a microcontroller to generate servo control signals directly. After all, a servo controller is really just a microcontroller running a servo-control program!

The Axon controller you link to looks pretty neat, but it’s also quite expensive, and you will not be able to use it directly control DC motors. If you don’t need all of those I/O pins, you might want to use one of the Pololu Baby Orangutans instead, which include a dual H-bridge chip that can drive two DC motors. Even with a programmer, it will come out a lot cheaper.

Nice work on your dancing robot! Any chance of posting a video?

-Adam

97

Ive updated the webpage, it includes videos now :wink:

But as you can see the robot just slide right off the floor, but i think that if i attach some kind of cupping glass or something else that attached itself to the floor a bit. Or you got any other idea?

-Sotu

98

Love the music video!

It looks like a plastic cup just shorter than the robot’s legs would be the perfect thing to keep it from falling over.

-Adam

99

You mean to thread a plastic cup on the outside of the leg?

And i dont get bothered by the falling part, its steady because of the support wheel, but it wont actually WALK. Or move fowards, as you see on video #2, it just stays on the same part of the floor, so i thought if something where attached on the underside of the carton, to make it attach slightly to the floor before the oposite legg hits the floor, making it kinda “dragging” itself over the floor.
It cant be to stitchy either, cuz then it will effect the movements. :wink:

100

I would also start to learn basic techniques of making my own circuit board for robots.
Can i make a board similar to the one in this guide: http://www.societyofrobots.com/member_tutorials/node/63
and use it in a robot? And learn techniques here? Or do you need different boards to different robots (i do understand that you need to modify the board, depending on what you want the robot to do)

I also wondered if it was ok for you that i used the robot code you gave me as my own in the robot contest im entering with the iBB robot?
Thnx