The basic stamp board doesnt work

PeterJiang

I use several hall sensors on the bs2 board.When I test one sensor,it can run on the debug screen
,but when I connect several hall sensors,and run the program,my computer told me that NO BASIC STAMP FOUND,then I go back to test single sensor,and it cant run,either!!
I'm sure that the circuit connection is correct,and the battery is enough,and change the com port,change resistor,change the wire....etc,and even change another bs2 board,but still no use.
But after one day,I do the same test,without changing any circuit connection yesterday,and it can run! But after I test multiple sensors,NO BASIC STAMP FOUND,too!!
Is that the bs2 board too old?Or other reasons?Could someone tell me what is the problem??

Mike Green

I doubt there is anything wrong with your Basic Stamp Board, but you've provided insufficient data to be able to give more specific advice. You need to make up a schematic drawing for your setup as it is really wired, not what you think it should be. There's often a difference between the two. Tell us what Stamp board you're using. You also need to post your code. Use the [ code ] and [ /code ] tags as described here:



Often this sort of thing is a power problem. With the additional drain of multiple sensors, there's not enough power for the Stamp to operate and the Stamp interpreter on the chip has to be running for the PC to see it.

PeterJiang

The code is just like this

Main:
DO
DEBUG BIN12 INS,CR
LOOP
END

And the circuit connection: http://www.floridaame.org/Plans/Kamran Nili/rpm/tachometer.html
the Diagram #7 and 8

And the board is the same on the diagram 7

Mike Green

You've posted a description and pictures of how to wire up a tachometer. That's fine as long as it works the way the article describes. That's not the case for you. It works sometimes and doesn't work if you modify the circuit. That suggests that something else is wrong. Usually this is a power problem. The display uses a lot of LEDs which use quite a bit of current. If you're using a battery, it may be exhausted. Leaving everything off for some hours, may allow the battery to "bounce back" enough to run things for a short time. When I ask for a schematic, it's important to supply one that's based on how the device is actually wired, not instructions on how to wire it. These are often different and that may be a reason for an intermittent problem or high current drain on the battery or whatever.

As I said, it is very very unlikely that there is any problem with the BS2 Board. You have to look at what you've added and any assumptions you've made in putting it all together. The assumption that batteries last forever is one of those ... actually 9V batteries have very little capacity and their output voltage can drop quickly under load.

PeterJiang

I just do the test on diagram 7 and 8,not including the LEDs test on that website.
So I just using only several hall sensors on bs2,no other device! Do only the several hall sensors need so many voltage?

Mike Green

Hall-effect sensors usually don't draw much current. Without an accurate schematic, I can't give you any suggestions other than use a new battery or an AC operated supply for testing.

PeterJiang

I eliminate the capacitance on the circuit,is that the reason it doesnt work?

Mike Green

What capacitance? Which circuit? The capacitance is probably necessary. Use a fresh battery.

playinmyblues_nscc

This is meant in a nice way although these comments often seem to not be so. The request for a schematic is usually a very good thing to ask for and when needed, to supply. Making sure you have done a schematic of the whole setup means that you have done your work. Not only that, by the time you have taken to draw up the schematic of the whole thing, you have usually taken the time to examine your device. This allows you to determine if there might be other problems with the device as it exists and sometimes to solve those problems on your own.

Providing the schematic also means that you will have taken the time to make sure that you understand all of the part symbols that are used and have gained further knowledge on how they are used and how they operate. There are a number of resources that can really help you with understanding electronics and microcontrollers. I recently posted a project I am working on and it pretty much explains the whole thing step-by-step while allowing the person taking on the project to work their own ideas into their own build.

I realize that this might seem like a thread hijack but I am trying to help. If you do not find this to be of help, then I apologize and you can continue along working. You can check out the project by looking up the term "Luna Mod Looper Basic Stamp 2 Version" on the Web. There is an Instructable.

Other great resources are:
1) Forest M. Mims books on electronics although I have never read one. He comes highly recommended and you can check out some current stuff in Make magazine,
2) Make magazine - and website,
3) Parallax's books - "What's a Microcontroller" and "StampWorks" among lots of other titles available for free as PDFs but also from the Parallax store as parts of kits. The "What's a Microcontroller" PDF is an excellent place to start when new to the BS2.
4) any Dummies, Idiot's Guide, or Evil Genius series or anything along those lines, and
5) Electronics_101 on Yahoo Groups - suggested reading is their FAQ or their equivalent on using the Forum/email group.

There are a number of other sites on the Web.

The StampWorks book is great for becoming well oriented with the BS2. There is even an experiment on how to use an MC14489. You can probably find out how to use a Hall Effect sensor somewhere on the Parallax website and make sure to check out the Nuts and Volts columns involving the BS2.

Two more things about micrcontrollers:
1) Every electronic device has limits. Make sure to examine the "Basic Stamp Syntax and Reference Manual" for current sink and supply limitations for the different versions of the BS2.
2) I had a project that had multiple devices connected to the same input. The readings taken from mutliple ADCs seemed to be a little buggy. It will probably take some time to figure out all the issues if you are using something like this. I used the StampWorks experiment #28 as the basis for this. Working out the issues would have taken a full schematic to ensure proper documentation and a full understanding of the situation.