complete a curcuit with two pins?

[orko007]

I am new to using picaxe chips and am currently just starting a project. my electrical knowledge is limited so forgive me if my terms are incorrect. I have read through the tutorials and did not see an answer of what i would like to do so i thought i would ask if it is possible.

I am using an 08M chip and would like to have it setup so that when a button is pushed a connection is made between two of the output pins. from what i have read this does not seem possible and i will need to use an separate switching device such as an optocoupler. but if i could do it within the chip that would be great.

Thanks for any help.

 

[jonphenry]

Could you elaborate more on what your trying to do please?

 

[BeanieBots]

It's not possible to make a PICAXE have "volt-free" contacts but it may well be possible to do what you want. Please give more details about what needs to be switched. Otherwise, as you mention, an optocoupler or similar will be required.

PICAXE outputs can be made tri-state but they will still be bound by Vcc & 0v.

 

[orko007]

I am working with an xbox 360 controller which uses a separate circuit for each button X,Y,A,B. it is not like the original controller when i could simply pull the connection for one of the buttons to 0v and get a reaction.

image of a 360 pcb http://orko007.phpwebhosting.com/360.jpg
With the 360 you cannot just pull one side of the circuit to ground. In the picture you there is a button soldered to the two connections to operate the 'X' button.

hopefully this explains a little better.

But it sounds like with what beaniebot said, if outputs are bound to vcc & 0v then what i want to do is not possible within the picaxe chip.

Another question which i have not searched on yet. is it possible to use the ser in on an 08M and an input or output?

Edited by - orko007 on 06/08/2007 22:44:48

Edited by - orko007 on 06/08/2007 22:45:14

 

[Tom2000]

Ah! You want to drive the button circuits with dry contact closures. While you can't do so directly with Picaxe pins, you can use the Picaxe to drive either reed or solid-state relays, then use the relay contacts to "press" the buttons.

You can drive a 5 volt reed directly if its coil resistance is above 300 ohms. You can find a suitable relay here: <A href='http://www.goldmine-elec-products.com/prodinfo.asp?number=G4194' Target=_Blank>External Web Link</a>

If you use one or more reed relays, add a suppressor diode across the coil. You can use any small signal diode for this. Make sure that you connect the diode correctly, with its anode wired to the Picaxe side of the coil.

A better solution, if you can find it, is one of the dual Form A solid-state relays packaged in an 8-pin DIP, such as the CP Clare LAA110 or PAA110. Panasonic and International Rectifier make pin-compatible equivalents. With these, wire a 1.8 k resistor between the Picaxe and each relay's &quot;coil.&quot;

For information on the use of serial communication, look up the 'serin' 'serout' and 'sertxd' commands in Picaxe manual 2.

Tom

 

[hippy]

Plus there's the 74HC4066 etc analogue switches which can be used like solid state relays.

 

[Tom2000]

Thanks, Hippy. And those are more readily available, too, I'm sure.

Filed for future reference!

Tom

 

[orko007]

thanks for the input guys I will look into these options. i will need something fairly small as space is limited. but im sure most of these items are available in SMT as well as DIP package.