Wow... that's a pretty big one to screw up. You could put a 10K resistor in parallel with the pot and that would make the total resistance always less than 10K. But, yes, it should have came with the proper pot.

You are trying to create a zero crossing detector? Check this out:

http://e2e.ti.com/support/amplifiers/precision_amplifiers/f/14/t/184352.aspx

You can use a decade counter to reduce the 500hz to 50Hz. It should work with a sine wave, but the output will be an integrated squarewave.

When you say ZCD, you are talking about a Zero Crossing Detector, and this is what is confusing. The Zero Crossing Detector is a function, not an input. Please post a detailed explanation of what you are trying to do from beginning to what you want as a result. That will better help people to help you.

LM565/567 or CD4046 Tone decoders?

You can play simple audio samples from the Arduino. Limited by storage space. An external serial eeprom would give you a bit more space for this.

The rest is fairly simple and well within the capabilities of the Arduino. You *could* bypass the tone decoders and use the arduino as the tone decoder. I have seen examples of this all around the web, but I have always been more partial to hardware than code since I am not an excellent programmer.

I just see no usefulness to this at all.

When the device was designed, decades ago, there was some usefulness.
I gave the reasons behind the inclusion of this capability two months ago, in the second paragraph of reply # 6.

Don

*Shrug*

No offense, but write it yourself, then. lol

I did not feel that it was useful enough to spend my time writing it, testing it, debugging it, refining it and maintaining it regardless of your reasons. If you do, then write it...

I didn't. Got pretty far, but simply couldn't convince myself that it was useful at all.

What you are describing could be handled with a simple text buffer. Since you are already in control of what is displayed on the screen, just manipulate it in memory and update or write to external memory.

If you put 'A' in row 1, column 1, you already know what is going to be in row 1, column 1.

I just see no usefulness to this at all.

Do you have the equivalent of the "PicBasic Bridge Program" for the arduino? Based on that guide, there is a program that is run on the basic stamp which is used to connect between the stamp and the module. If you don't have that on the arduino, then I would imagine it would complain.

I think the problem is trying to run things off of 5V on the external jack. While current will pass through the 5V regulator, there will be some voltage drop which is probably causing a Brown Out reset. Plugging in the USB cable maybe gets the current flowing enough. Seems odd, but then microcontrollers do some odd things when the voltage gets a bit too low.

Take a voltage measurement at the 5V line while trying to power it this way.

Ideally, you need at least 1V higher than the regulator to work properly, so 6V minimum. The Arduino site says 7.5V

The simplest way is to use the servo library and just use servos to push the buttons if you cannot modify the fan to just connect to the buttons directly.

It came from the web interface. On the Atmel site, you just select Product Search. But I find that clumsy, so I just downloaded the data to excel and got rid of fields that were not relevant and rearranged the columns by what was most important to me (and probably most people.)

So I didn't really do anything special. If you are able to put it into a web interface, go for it.

Nothing magic. But I downloaded the ATMEL parametric search for both the Mega and Tiny AVRs and converted them to Excel with filtering and ease of viewing.

I also broke out into another sheet just the devices available in DIP packages for most hobbyist prototyping.

Thought I would share...

 

Consider the use of RFID temperature sensors. Each one would have a unique ID, completely wireless, no power needed. And they would follow the frames around regardless of where you put them. You pretty much just encapsulate them and drop them wherever you want.

You may need a RFID reader per box, though because the range of RFID is generally limited (however, there are ways around that.)

http://www.phaseivengr.com/p4main/Sensors/WirelessTemperatureSensors.aspx

Based on my parametric search, the ATTiny43U is probably the best processor for this. It operates .7v and 5.5v, and is one of the picopower processors (very low current)

The only real drawbacks are that it has only 256 bytes of RAM , so you may have to write assembly (your code is so simple, I don't think you would have trouble with that), and it doesn't come in a DIP package (but does come in a SOIC package.)

Also, as a tip, the slower your clock frequency, the less power the AVR will consume. And make use of the sleep() function as much as possible.

All in all, the Arduino core is not ideal for this application, really. You might use it for development, but for a final application, I would look at writing assembly code.

It's not a good idea to just supply a bit more power than you need. Overestimate then double that and your PS will live longer. Same with a PC, always get extra power supply.

But then on the flip side of that, when something goes disasterously wrong having a huge supply of current available, your circuit will turn to bacon long before the power supply trips whatever protection it has or blows open itself. I guess it depends on whether you want to replace the supply or replace your entire circuit. GoForSmoke indeed!

(Just teasing... it is a very good rule of thumb -- but consideration above is real.)

A bone regarding soldering?

You will need a soldering iron and some solder at a minimum. The solder is made of a metal that will melt at relatively low temperatures (relatively for metal). To get a good solder joint, make sure that you are heating both surfaces equally and apply the solder to the point where your two surfaces touch. The solder will melt and will flow along the metal. The reason for making sure that both surfaces are fully heated is that solder flows on hot surfaces, but puddles on cold surfaces. So, you would have a weak connection (called a cold solder joint.)

Generally, don't apply more solder than you need and only use solder meant for electronics (not plumbing or 'electrical' solder for eaxmple.)

Obviously the iron will get hot, so either buy a stand or an iron with a stand, and keep your fingers out of the way.

If you have the cash, get a good soldering station that has a temperature control. This is a tool that you will end up using quite often if you are getting into electronics as a hobby.

You may not agree with that approach, but at the end of the day it is up to me to decide what advice or help I give, and you must do the same.

Absolutely. I apologize for getting snippy earlier. In general I was irritated with that sort of attitude (and I still stand by it) but looking at it later, I don't think your post was a good example of what irritated me. So, my apologies, Peter. I just managed to get my knickers in a bunch, that's all.