Let's Make Robots!

Making an variable strength magnet

I am in need of magnets where the strength of the magnet can be varied. Specifically I need 3 "settings", off, low and high. Low would be where the magnets have enough strength to connect but not more strength than they can be pulled apart. High would be where they connect but can't be pulled apart.

A long time ago, in a galaxy far, far away...

Quite a while ago, Fritsl suggested another LMR Skype weekend. Either that already happened, and a spammer brought the forum up a few months ago, or it lost interest.

Anyone feel like having a Skype weekend anytime soon? I have a microphone now, so I can finally participate!

RC RF directional beacon

I am still wondering if it is possible to create a simple, cheap, fairly accurate, directional beacon for outdoor use. And I keep thinking I should try to re-purpose an RC transmitter. So here it goes:

Would you deem it possible to create a directional antenna for an RC transmitter?

Would this antenna be able to rotate? Fully continous, or just 360 CW followed by 360 CCW?

Which RC system would you consider? There are so many frequencies in use. And modulation types.

LDR problem

Hey i plan to make a robot that has no brains at all. but the LDR's are not working! they were working in the previous appliance (outdoor light) but not now with a battery,motor and an LDR and it won't work! here is the schematic for my robot.


My Schematic                                                                        Can you please tell me what is wrong!

Robot that connects to the internet?

I have seen loads of robots that are controlled via the internet, but I wonder if anyone has ever made a robot that actually gathers information from the internet?

Such as...Looking at an object, and then by you "tagging" certain sites, like Photobucket or Dictionary.com, it would find a picture that looks relatively similar to the object it found, and then it would "read" the keywords to see what that object is. (So it would say "Oh. The majority of people on the website say that this object is a tissue box, so I am seeing a tissue box.)

28x2 Board --Your Wish List

Well, with all this Walter work going on, I find myself sorta longing for a small, fun tabletop robot --just to play with. I was looking at the standard picaxe 28x board and again, I remember how much it really sucks. No EEPROM space, ADC's have the data pin in the center, no HPWM output to the motor driver etc. etc. I know I have asked this in the past, but my PCB designing skills have gotten a lot better sense then. So, I ask again...

What pisses you off about the current 28x picaxe board and what would you want if you could have anything?


Getting the right reed switches and magnets

I have a setup in mind, which involves a magnet put next to a reed switch, times 2. So it should work so that a reed switch is only activated when two magnets are stuck together and next to a reed switch, and deactivate once there's only one magnet next to it.

So I have found a couple of products from this at Sparkfun:


School project tank robot


To finish my education i have decided to make a tank robot as my project. But i cant afford it to cost to much, as i am not sure how much time i will use on it when i am done. And if i decide to spend more time on my robot, i realy want it to be able to drive around outside. (more fun)

First problem i have runed into is, damm tracked based chassis cost alot. And most of them can only be used indoors. Any1 know some good cheap track based chassis that dont cost to much? And some motors/gearbox.


Just saw this posted, scheduled for January 7th. Hope I can get some toys here :



how to build a manual combat robot within 3kg lmit

i have participated at a tech fest and hav 2 build a combat robo help me