Let's Make Robots!

Volts and Amps... For Dummies

Well Folks,

It seems that I might be turning into the lay-person lingo translator around here so I thought I would use my new-found position to start posting some basic concepts...

I have noticed a lot of posts about running motors, motor drivers and the like so I thought I would do a post about one simple thing, there may be more to come.

Today's lesson is volts, amps and logic signals.

Here we go...

Volts are water-pressure and amps are the diameter of the pipe.

I need to build a BIG motor controller

Simple question,

I need to run a motor drawing between 7 and 10 amps at about 18 volts. (I think a similar question has come up reciently)

I am looking a these which is a big brother to the L293D. It says it will handle 2 amps per channel.

Question: Is it as simple as ganging up in 5 of these units in paralell to get my 10 amps? 


Question IRIN Command Picaxe

I am using the irin command right now and am running into a really simple problem...

It goes: irin [timeout,address],pin,var 

The timeout is how long you want it to wait before skipping ahead to the address and the pin and variable are pretty self-explanitory. What I want to know is, what address do I use if I want it to just go to the next line of code? I don't need it to go to a whole other place in the code, just the next line. --Any thoughts?

IR Distance Sensor Placement

Well folks,

I have now upgraded to a total of 4 Sharp IR distance sensors on a single robot (in addiition to a sonar sensor in the middle on a servo). I want this bot to drive entirely off the IR sensors leaving the sonar to simply find "interesting" things to drive toward.  In the past, using only 2, I have tried many different placements... I have tried:

One on each corner, shooting straight forward

From the middle shooting out to the corners

On each corner shooting to the opposite corner (crossfire)

Help with Variables in Basic

This is a chunk of code I am using for my big tracks bot. I am using a irin command to accept inputs from a tv remote i.e. 2 is fwd, 4 is left, 6 is right etc. I am using #5 to goto my write command to enter the number of times I have hit each button onto my EEPROM chip. The Problem I am having is that the variable changes!! I have no idea why. Here is the code with some notes as to the problem. Any ideas?


EEPROM Addresses, Blocks, Nooks and Crannies

This is a general post to discuss the in's and out's of how much and where data is stored in an EEPROM.

My first question is with a 24LC16B. I am led to belive that, using the slave code and switching through the "blocks", I should have 8 blocks and 256 spaces per block to stick data. I am open to any ideas, explainations or tutorials.

i2c new to me...

Allright Folks,

One of you all's gunna need to explain this whole i2c thing to me. I have done a wiki (which confused me even more) and a few google searches. What I have got so far is it is an extra little storage space that a pic can talk to. I guess there are "packets" of bits and addresses or something like that but really, I have no idea.

 Can someone explain this whole i2c thing and include some basic, pratical uses (and how to do it) when being used with a picaxe. --Explain it as if you would explain it to a 4-year-old.

Help with smoking pot(s)

Well, I thought this would be simple, I'm a bit embarrassed really. I was hooking up a simple 5k potentiometer to one of the ADC inputs of a picaxe28. I had +5v to one terminal gnd to the other outside terminal and signal to the center pin. I used readadc and a debug and the set-up worked and did what I needed, however after about 20 seconds came the evil blue smoke. What did I miss? Man, I feel like an idiot -such a simple thing to hook up. Any ideas?

Help with a charging circut...

Hey guys,

I have been playing with a LM386 amplifer chip. It's a great little simple chip and takes very little power. I soldered together a little stereo amp and added some crappy little speakers for an iPod speaker system that I can use in the kitchen while I cook. Here's the deal, I was wanting to run it off of solar PV cells as there is a perfect window just above the sink. I am guessing that I would be charging between 4 and 6 AA's for it's little battery pack.

So here's the question:

GM3's and a 9V

Has anyone run any of the GM motors (GM3 GM9 etc) off of a 9v battery? I was thinking that after the 1.5v drop that the motor driver takes, the motor will only be getting 7.5v. --That's only a little tiny bit above the 6v specs. Anyone tried this? Or does anyone have a idea of how bigga resistor to use to drop that last volt and a half? --Any thoughts you got, folks.