THere is a requirement to generate hi level,lo level and open position.
the simplest way is with spdt switches, power line and ground.

there is curiosity to automate it..

is there a simple automation with electronic switches?

let me know if you have seen products already in market..

jis

 

Too vague to give a useful answer can you give more details?
Max.

 

What will these switches drive? Is it an input to a digital signal? What will drive these electronic switches? A digital output? Do you have a schematic?

Have you considered analog switches, in the 4016 or 4066 family? Do they satisfy your requirements?

 

Some of the Digital inputs are pulled up to Vcc and some are pulled down to ground.

Digital inputs pulled up to Vcc are normally active lo and ones pulled down to ground are active hi.

For test purposes,

Active lo signals are connected to ground thru a switch.
Active hi signals are connected to Vcc thru a switch.

But switches are manual switches. Can i convert this to software controlled switches without an additional micro?

thanks,
jis

 

...
But switches are manual switches. Can i convert this to software controlled switches without an additional micro...

What would this software run on?

Ken

 

I am trying to do with a computer and communicate over rs232/usb..

 

Then you're going to need an external relay board/box that communicates via USB, and appropriate control software. Such as: http://www.google.com/imgres?imgurl=http://www.denkovi.com/ebay/EBAY_NEW_update/USB%25208%2520Relay%2520Board%2520-%252012V/HTML/12V_2.JPG&imgrefurl=http://www.denkovi.com/page/22/usb-eight-channel-relay-board-software.html&h=972&w=1200&sz=390&tbnid=0Yo-XX12dQHmoM:&tbnh=84&tbnw=104&prev=/search%3Fq%3Dusb%2Brelay%2Bboard%26tbm%3Disch%26tbo%3Du&zoom=1&q=usb+relay+board&usg=__ACIHZgL_I1r875tabMepyiTQM7E=&sa=X&ei=9R5AUoXKBaLbyQHopYCQAw&ved=0CDIQ9QEwAA

Google: USB relay board

Ken

 

The scope of the project is still not all that clear, for example if it requires no operator input then there is a project already out there called a Smart Relay.
Made and relabeled by several manuf, Seimens, Omron, Idec etc.
Max.

 

Smart relays are costly ..

My budget is only 100 USD..

Scope: the device i make will be used for software testing! we can simulate real conditions with a switch.. I want to automate these switches and make it generic..for multiple programs..

thanks,
jis

 

4066 quad bilatteral switch. Inputs, ouyputs & control are all logic levels.
Dashed line is control. Output, pin 10, is Hi if top control, A, pin 11, is Hi & bottom control, B, pin 12, is Hi.
Output Lo if A is Lo & B is HI.
Output Open if B is Lo.

 

So, you need X number of tri-state (hi-open-lo) logic-level signals individually switched by a USB or serial signals form a computer. How many? What type of logic are these driving...TTL?...CMOS?...???

Ken

 

@KMoffettAs : as many as 32 IOs are required .
My high could be varying in the range 8-15V

 

32 I/O's? Or do you mean 32 "outputs" from you automated signal generator? The signal outputs must be variable?...all simultaneously or individually? And they must be tri-state? And they must be able to provide how much drive current?

The devil's in the details!

Ken

 

1. yes, 32 outputs.
2. if i hook up a 12V supply, I need a 12 V output, a 15V input should give me 15V output ( Not necessarily variable output)
3. Tristate is only to simulate open condition - not pulled up to high and not pulled down to ground,
4. 100mA per channel will be great!

 

Do you see the difference between post #14 and your first post? It's hard to help when you don't provide all the details. What are you driving that needs 100mA? Resistive or inductive loads?

Maybe you can explain exactly what you're trying to do...the overall project.

Ken

 

@KMoffett : attached is a simple example of a high and a low with manual switches. There are 3 possible combination altogether., high,low and open.
I want to automate these switches from my computer.

I will have like a maximum of 32 hi or lo switches..

hope this is clear

 

OK, you need to address 64 different states. Hi/Lo logic for 32 the outputs, and Logic/Open for the 32 outputs. Can you serially change each of the 64 states, and then do whatever the purpose (might help to state that) of this operation is? Like you do manually with the the switches. Or, do all the new states have to be presented at the outputs simultaneously?

Ken

 

It will be either hi state or lo state or open. not all of them simulatenously.
All 32 outputs can be in one of the states hi,lo or open. Practically all outputs can be in hi OR lo OR open state.

 

It will be either hi state or lo state or open. not all of them simulatenously.
All 32 outputs can be in one of the states hi,lo or open. Practically all outputs can be in hi OR lo OR open state.

I don't understand! Can you explain what you are doing. What's the circuit/system/project that this is to control?

Ken

 

All of your combinations, I believe, can be implemented with 4066, or we still do not understand your question.