There is way too much power in your iron! Replace it soon. Don’t use that tool of torture on your poor robot!
Even worse: your soldering tip is probably a mess after melting all that led. A proper electronics tip will ce cleaned after every user (that means every other joint you solder!). And retinned before you switch it off. All this to prevent corrosion/oxidation of the coating on the tip.
Don’t bother to get experienced with a glazers iron, unless you are glazing. Buy the proper tool. Some generic electronics iron will do. Probably between 20 and 40 Watt. This is the one I use. Don’t spend more money than that, unless you are sure to spend hours every day using it.
So, I tried spinning the wheels by hand. The faster motor seems to be slightly more difficult to spin. There is not a huge difference though, in fact, I had to get a second opinion. The person I asked said the same thing… but are not certain. From what I gather from your comment is, if they are different ratios, the difference will be very noticable. So… I am not certain now.
I have not tried the PWM thing yet.
My robot works perfect other than the motors with different speeds, it reacts properly when I simulate obstacles while it is sitting on a “match box”.
I have posted the requested pictures, a video of my robot going in circles when it is supposed to go straight, and a pic of the receipt. I am not sure what you need to know about the kit… I do know one thing, the shrink tube that was included was way too big for the wires as you can see in the picture. They wouldn’t get any smaller no matter how long I heated them. I can’t take pictures of all the parts included in the kit because I have already assembled the robot. There is a number at the top of the receipt that says GST #885910364 and receipt number is 106048. I also got some nice LMR Stickers!
Couldn’t get the video to imbed, so here is the link:
Ok, I’ve played around with a few things and have some more data.
Sometimes, after I send new code out to the robot, and set him down on the ground, sometimes the turn is not as pronounced. Now, I have been careful not to let any of the parts move, so my results aren’t skewed. Sometimes he makes a tight 1 and a half foot diameter circle, sometimes he makes a five foot circle. The five foot circle is almost bare-able. But now that I reprogrammed again with the full code, it’s doing the tight circle again. It seems to do it at random, no matter what code I am using
Other things I have tried have included switching which output it is connected to (ie. moved the slower engine to A and the faster to B). I have tried adjusting the wheel base to try to account for the slower wheel.
I suppose I should try the PWM thing now. Hope it is not too complicated.
this may sound stupid but, have you tried glueing the wheels onto the axles? I remember having a similar problem and it was one of the wheels slipping on its axle.
Yeah, thanks for the suggestion, but it is not slipping. The mount for the wheel is specifically designed for the motor. The mounting bracket is not circular, it’s like a beveled edged rectangle and they snap right on snug. I have also tried taking the screw off both wheels, because I thought maybe the slow one was screwed too tight. None of the wheels are rubbing against anything either.But, it still runs slow.
As for now, I am rebuilding. Because I think I can construct it more solidly. Then I am gonna try the PVM suggestion by fritsl.
Well, I completely rebuilt the robot from the ground up on my own. Did a few things differently this time. Resoldered all the wires again too. Found some sturdier double-sided tape. Now my robot is Sturdy. I used the bigger battery pack this time, as the kit includes a 3 x AA and a 4 x AA. The 3 x AA I used originally just wasn’t enough space. The Robot goes much straighter now. It still goes in a circle kinda, but it’s only slight now.
One problem I am running into now, sometimes the left motor stops completely and I have to manually turn it with my hand to get it to start up again. I think I am going to order some parts and change some things. I want to try and get better and much faster motors. These ones are slow and kinda cheap. And maybe get a better sensor. While I am waiting for parts I am going to play with programming some more. Any suggestions on a better sensor and motors for a beginner like me?
Oh, I just wrote a mail to you, to get this answer, sorry, did not see it was a seperate post. Sorry.
Thanks for posting this. I will make sure the heat shrink will be better - and the video is very informative; There is something TOTALLY wrong here! Forget all about PWM!
Please, try to just give the motors power right from a battery. You can let the robot stay assambled, but power it from battery alone, to motors, one way or the other.
If it still goes in a circle like that, you need to get replacement parts.
If not, then we are closer to finding what is wrong here. But forget about PWM, this is something way worse, I thought you where talking about a litle drift to one side- do not understand all the talks about feet, I am metric
If you want fast, accurate help, please post videos next time as well, saves us much time!
Thanks for the help! My robot is functioning properly now. It goes almost perfectly straight now after a complete rebuild. Sometimes one of the motors completely stops functioning now though, to get it started again, I have to manually turn it. I don’t know if a connection is loose, which I doubt, because when I play around with the wire it doesn’t effect it. I think I may have damaged the motor somehow after resoldering so many times(I kept breaking my welds).
I have since tweaked the programming to suit the “intricacies” of my build and added some conditions that cause the robot to go in reverse if it gets stuck in a three walled corner. I’m going to add more when I get home from work to account for other situations.
I have also added a power switch, which is extremely helpful. It is very hard to fumble with pulling a battery out when you want it to stop. I broke my robot at least a couple times this way. Maybe that’ll be something to think about adding to the tutorial.
Thank you frits for the great tutorial and thanks everyone for your help. Thus was a very rewarding experience. Not overwhelming at all and it makes me want to build more robots. I can’t wait to get home from work and start tweaking it some more.
Do you own a multimeter yet? It is worth ten times any part you could buy for the same money. Always tools before parts!
Your slow motor could be diagnosed with a meter. Compare resistance of the coils of the two motors. Measure voltage given by batteries. Measure current of motors under power. Etcetera.
Yes, I have a multimeter. I Yes, I have a multimeter. I guess I should check it out when I get off of work. Thanks for the idea. I have purchased a New soldering iron too, with adjustable temperature. I also got some styrene, so I can give him a proper chassis. Any other recommended tools for a beginner?
My Recommended Tools (roughly in order of usefullness to me):
Decent (not expensive) wire strippers
Small and medium sized needle nose pliers
Small and medium sized diagonal cutters (dikes)
Utility knife with sharp blade (available in a couple of blade edge thicknesses, I like the smallest)
“Helping hands” (wieghted based with two adjustabel aligator clips, sometimes with a magnifying glass)
Bright worklight to save your eyes while squinting at tiny parts
Jewelers screwdriver set
Useful Materials (no particular order):
Several small and medium breadboards
Several small and medium proto boards (solderable)
Electrical tape
Stranded electrical wire in several colors (I think I use 16 gauge)
Solid electrical wires in several colors (16 gauge again. This is for your breadboards.)
Stock of a wide variety of bulk 1/8 and 1/4 watt resistors (you can usually find a bunch for cheap in quantity)
Stock of a wide variety of bulk electrolitic and ceramic capacitory (you can usually find a bunch for cheap in quantity)
Stock of a general NPN and PNP transistors (the pn2n2222a is my fav for a general NPN. Some NPN and PNP transistors are identified as complementary pairs, which work well in a circuit together.)
Stock of a a few NPN and PNP power transistors for things like driving motors (TIP120 series includes NPN and PNP transistors are identified as complementary pairs, which work well in a circuit together.)
Stock of a general diodes.
Stock of a variety of LEDs (different colors, multicolor, flashing, high brightness, etc)
Stock of actuator switches (pushbuttons, switches, momentary bump switches, etc)
Stock of paired gear motors
Stock of different sized wheels
Stock of your choice of processor and supporting boards/chips
an oscilloscope is very useful, a used analogue model from ebay should be fairly cheap. Buy one with the highest bandwidth you can afford, something around 100-200mhz would be perfect, but if you cant afford that even a 10mhz model would be useful.
So, I recently decided to rebuild my starter robot for the third time. This time with a body. I have constructed the body and so far, I am pretty proud of my work. I have also added an LED that turns on when he is evaluating obstacles and an on/off switch.
I have new issue now. I had a bad motor, sometimes the left wheel would not turn unless I started the rotation process by manually spinning it with my hand. So, I did some troubleshooting, it does this even when connected to batteries by itself. So, I know the motor is bad. Anyway, I destroyed my solder joint again and now the copper mount is broken, so that motor is in the trash. So, I bought two new motors from the local hobby shop. They are clearly faster, even though they were the slowest and cheapest In the store. Anyway, I hook them up and they clearly need a little more juice than the old motors. They work fine with four double AA’s. Problem is, i am worried that, if I hook up the sharp ir, it will fry. So, I guess my question is, how can I get either reduced power to the sharp IR? Or maybe, is there someway to get a separate power source to just the wheels and still be able to control them with the picaxe?
Am I getting into something that is too advanced for my skill level? Should I just reorder a new set of the gm9 motor that comes with the kit?
Guess I should have RTFM. I see that the picaxe board has a two power supply option. It’s still a little fuzzy for me though. How do i know which devices are getting power from which supply? I suppose that would be what the multimeter is for. But can anyone tell me off the top of their head?
thanks,
Ps, sorry about the double post, 3G been acting up and I didn’t think the first one went out.
NVM, I get it now. The pins NVM, I get it now. The pins go v1, v2, G. This explains why I got kinda confused when trying to hook up my LED. Sorry, I’ll try not to post a question until I am certain I either can’t find it in docs or until I don’t understand the docs.
Now, I do not expect you to read that page now, because I have promised you that you will building building the robot as fast as possible However, it is important that you read that page at some point, to learn about the board, and the microcontroller. Promise me to get back to that, make a bookmark for next step
You can delete a post that no one has yet commented on. I just logged in as admin and did it for you.
i need alternatives for picaxe-28 project board … cause i havent that in my country…also i still wait the bundle that i need… but till now it not deliverd to me …
so if there are an alternatives for picaxe-28 project board i need its to playing with this robot …
However, it is important that you read that page at some point, to learn about the board, and the microcontroller. Promise me to get back to that, make a bookmark for next step 