Those adapters often have a capacitor across the output pins to filter some of the ripple in the DC that is left after rectifying the AC. A capacitor with hold a charge for a bit of time after the unit is unplugged from the wall if it has nothing attached to the load side.

Now you have some more things to study - capacitors and rectifiers. Keep this up and you will have the stuff I paid good money to learn in my first semester when I was in college.

Don't feel too bad about being snowed under by all the terminology, you can look on wikipedia and other places on the web and you should be able to learn what all this means. Not knowing your background, but it shouldn't take too long if you want to learn it.

And don't feel too bad, some of the old timers manage to mess it up and have to go back to class to remember some of this fundamental stuff that makes up the basics for all these electrical toys we play with.

 

Depending on the value of the potentiometer it will have minimal effect on the circuit. 5V and 1k doesn't make for much current, and a larger value pot will draw even less current - you are using the pot more as a voltage sense than for current anyway...

The seven segment display will be more of a source of current draw. Though you will have to limit the current (to limit the voltage across the segments) with a resistor going to each Arduino pin.

I have a little shield that I made to play with analog and LEDs that has 2 pots and 7 LEDs that all work at the same time from the same 5 V on the Arduino. As long as you don't try to run too much current through any pin and you are drawing less current than the 5V pin can supply you should be fine.

You can use your Arduino board as an ISP by loading the ArdunoISP sketch (You want to use Arduino 0.22 rather than 1.0 to load the ArduinoISP Sketch) and then you can program other ATMel chips. You might want to search using the phrase - Arduino as ISP and you can see what others have done.

I made a small board that I can attach to my Arduino and with it I can program a variety of 8, 20 and 28 pin ATMel chips.

You want to get ArduinoIDE 0.22 and use it to load the ArduinoISP sketch into your Arduino board. There is a problem with loading the ArduinoISP sketch from Arduino-1.0 as something was changed in one of the libraries and it doesn't work at 19200, but at 9600 and there are other files that would have to be changed also.

I have used the ArduinoISP to program several ATMega328 and ATTIny2313 and it works just fine.

You can easily make a programming board that you can attach to your Arduino for programming your board or 328P chips. Or you can use jumpers and do it without any additional hardware. I made a board so I can

Get a copy of Arduino 0.22 and from that IDE load the ArduinoISP sketch into the Arduino.
 (there is a small bug with ArduinoISP and ver 1.0 that keeps it from working properly)
Once you get the ArduinoISP sketch loaded from V0.22 you canuse either that version or 1.0 to load the Bootloader.

Disconnect your arduino from power
Connect arduino and your new board
Arduino   New Board
 D10         Reset
 D11         pin 17
 D12         Pin 18
 D13         Pin 19
 Gnd         Pins 8 & 22
 5V           Pins 7 & 20

and on the Arduino connect 5V to Reset with a 120 ohm resistor.

Hook things back up and under Tools/Programmer select Arduino as ISP and then select Tools/Burn Bootloader.

There is a possibility that the chip you are using returns a different ID code than the 328P on the arduino and if so youwill need to use AVRDude from the command line. If you have to do that yuo might want to install a copy of WinAVR(it sets up the path and such so it works smoother) and go that route. If you need to do that I can get you that info and the command line commands to configure you chip. Once you get the 328 on your board programmed you should be good to go.

I have added a couple pictures of my ArduinoISP board that will work with 8, 20 and 28 pin devices.

Yeah. That's where I'm heading now. Gonna get an ISP, go barebones and low power. My first real Italian Arduino was a great start for me.

You don't need to get an ISP. You already have an Arduino and that works just great as an ISP. The Arduino ISP Sketch that comes with 1.0 has to be changed to 9600 baud, or you use .22 and you can run it at 19200. 6 wires and a 120Ohm resistor and you can program chips all day long.

do a search for  - Arduino ISP

It is not readily available, but -

There is another way of accessing I/O that has some potential for problems...

Search for PORTB and DDRB and PINB (and PIRTC, DDRC, PORTD and DDRD

These are ways of accessing a port directly so that you can read or write multiple pins at one time.

You can still set up the pins in the normal method and then use PORTB to read them.
If you look at the Arduino pinouts you will notice that they have notoation like this
328    Arduino
PB0    D8
PB1    D9
PB2    D10
PB3    D11

so you could do a quick read of pins d8 through d11

   MyVar = PORTB and 15
if myvar = 1 then track 1 was tripped
= 2 then track 2, 4 tehn track 4 and 8 would be track 4.
Combinations would mean that there was a tie.

you could then loop waiting for finisher 1, another loop for finisher 2, another loop for finisher 3 and then assume that finisher 4 was whoever is left.

When you check each bit individually you are increasing the chance that you will miss a car if they are close.

Pulling the reset pin to ground will reset your program. It will work and cause no problems.

Most folks like the more elegant method of having another input that resets your counter to 0 and any other initial conditions that you need to set.

Thanks.  So, basically you should usually set the signal first, then turn on power.  This application involves 100-2000 servos, of which only about 5% are in use at any point in time.  So really my issue is power - I don't have enough power to control them all at once, so when I go "attach all servos; set all servo angles to init angle; power on all servos" they all just get stuck because none have enough power to move.

I'm initially just doing about 80 servos, so if I just got a bigger power supply then I could go with your suggestion and avoid the transistors.  The power supply I have at the moment is 1A, which can move about 20 at once, so 10A should cover it easily.  Might do that for the moment thanks.

Sounds like you need to look into multiple power supplies. I am assuming that these servos are distributed around some structure and multiple supplies would make for more reliability.

Commercial source would be Boston Gear.

You might also check and see if you have a local bearing and power distribution distributor as they often carry timing belt drive parts, sprockets and chain and gears. And they are often very competitive on pricing.

Get yourself a copy of the data books for the ATMega 328 and whatever chip is in your nano and you should be able to figure what pins are available to be programmed.

The Uno is an excellent starting point because just about everyone working with these devices knows what one is and what to expect from it. If you get into these devices it even makes a good programmer (with the ISP Sketch) for other chips in the ATMel stable. I have used my Arduino Uno to program the ATMega328 and the ATTiny2313 devices and there are others in the family that would be just as easy to program and use.

But the Arduino is a good starting point to learn from.

Now I feel more at home; thank you for your reply. Now if I could only spell "Termonology"
[/quote]

If you could spell you would be a stuffy english major.

As is you are an inquisitive and adventurous geek-to-be... Beats an english major any day. (small 'e' was deliberate.)

You probably won't get rid of servo glitches on startup. What you are most likely seeing is that the H-Bridge that drives the motor, along with other circuitry inside the servo is not turning on cleanly and this is what causes the servo to jump. In many applications this is not a problem because, if the transmitter is on the servos quickly respond to the current control positions. You are going to get some twitch, it just depends how quickly teh control signal is there to move them where you want them.

You might also look into a small relay. Would handle power to all you servos with one device.

Yep -

You might need to hook up a capacitor to the lead going to the base of the transistor (arduino pin 5 to ground). What you are hearing is the PWM signal in the motor. PWM Is not quite analog, but does have some of the properties (most of the time...)

You might have a problem - the motor might be designed to run in a certain speed range and won't perform well outside this range. If you want slow rotation you would be better off with a gear motor or a stepper motor.

Try starting the motor at PWM of 255 and slowly reducing that number. You need enough torque to get the motor started and then it will require less torque once it is moving.

What is this motor conected to?

Angrily (tired at this point), I picked up my mini vice and with a well aimed (all be it accidental) shot, managed to put a rather large dent in my guitar!! LOL.

Sounds like someone needs to grow up or get some anger management classes... Sure wasn't worth the mark in the guitar and didn't help the vise any...

How far was it turning? Was it repeatable. Those 2 will give you quite a bit of the answer of whether it is working. Next is - How fast are you stepping? If you are stepping too fast you WILL miss steps. Could just about drive this one directly from the Arduino - just add diodes across the windings. (Diodes won't conduct when the Arduino is at 5 V.)