Let's Make Robots!

driving motor with bjt

i want to thank every body here for this usefull forum and the great answers i have found.

I want to run applications with PIC MCU but PIC can not sink them(like DC motor).so i need transistor.

but as i look to for example C945 datasheet,the betaof transistor is not specified!!!!!!
only a range is specified for beta.

so how can i have precise design to let my transistor work with the exact CE current I want????? 



what is wrong with my code?!

i dont know what's wrong with my code!

i made a simple code that should make my robot simply avoid walls, stuff etc.

i placed SC-QR-1 (my robot's name) upside-down and pressed [F5] (the "run" shortcut) and watched him move his cute little robot legs..     WTF?

the new code seemed to work untill the walk part was over and he started to turn..    ..left.        and then again left and again and again..    etc.

he is suposed to keep walking!!!

dumb question about capacitors

Hi all,

I recently added a 0.01uf capacitor across one of my ICs ("decoupling"). Thanks for the advice guys.

It works great at supressing electronic noise, but I don't understand HOW. It would seem to me that connecting the positive right to the negative would shut the whole thing down. But obviously it didn't. So what does a capacitor's uF value mean?

How much current is allowed to pass through it?

Or how much current it stores at any given time?

Begineer here help me

 I am doing my B.E in Automobile engineering ,I am intrested in robotics , so i need help to do some projects that is very basic

Using eeproms with picaxe MCU

I'm new to programming picaxe microcontrollers, I've only made and programmed one device so far which was a programmable drillstop for work using a 14M. This is why I'm building Junior, so I can experiment with the programming. I'm now using a 40X1 with an i2c bus and an eeprom expansion board. After reading through all the picaxe manuals and the i2c tutorial it seems to me that while I can store data on the eeproms, eg. maps of the rooms my robot has made as it explores, the system won't let me store additional subroutines that might not fit in the 40X1's flash memory.

Help with 555 circuit.

Well, I have got the 38khz distance sensor working in picaxe form.



Now I am trying to wire-up a stand-alone unit with a 556. Now I know this is a RTF(data sheet) moment and I know the resistor/resistor*cap/2 (or whatever) equation, but the final circuit is still above my head. Are there any of you circuit guys out there that can do a little drawing for me? Maybe with a couple pots for fine adjustment? I plan on the final output going into a picaxe using the pulse-in command.

Thanks in advance.

picaxe or arduino automated ball pick up?

I have a picaxe and an Arduino, I'm trying to make a robot that scans for a golf ball, picks it up, then returns it to me, I found the CMUcam, but it is very expensive, is there an easy way to do this task? Am I overthinking this?



thanks :)

Beginner Here, Need Some Advice...


My Greeting to all of you part of this site, its awesome.

So, I am a student of Diploma in Electronics & Instrumentation in India, & I would very much like to make a robot myself but i am a novice here & don't know where to start.

I have the following knowledge

1) Good Grip on C & some knowledge on C++

2) Knowledge on Basic Electronics, Analog & Digital

Do I qualify the necessary knowledge to understand & build a robot ?

Moreover, how much it will cost to build a primary robot ?


hacking toys

hey all,

i'm trying to take apart a bunch of toys and other small electronics. They all have a push-button that mashes down on the PCB to operate. the spot underneath the button looks like this: (forgive the hasty visual):delete-me.gif

I think that the push of the button connects the two. So my question, then:

What's the best way to get "electronic-ize" this so my IC can do it?


-solder them together and turn the power on/off via my IC?

Picaxe programming, problem with head turning and scanning.


Picaxe programming, problem with head turning and scanning.


For some time now i have been playing around with my code to get it just right, but i have hit a snag that i cant seem to fix.


If you are good at programming you will see the mistake