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Electronics => Electronics => Topic started by: zabuza™ on March 02, 2010, 07:04:16 AM

Title: Sensor to computer
Post by: zabuza™ on March 02, 2010, 07:04:16 AM
hi i was wondering if this would work.

i want to connect sensors to computer without going through a micro controller. i did some research and i need an a/d converter but i don't know what else to use.
Title: Re: Sensor to computer
Post by: Hewhowalk on March 02, 2010, 07:21:19 AM
You need some sort of logic that is responsible for transmitting the data in a way that the computer can interpret (protocol). But I would recommend you to make it easy and buy a interfacecard of some sort with all tha logic and circuit ready-made. Google "the namn of your sensor +computer interface" and you shouldd find something useful.
Title: Re: Sensor to computer
Post by: waltr on March 02, 2010, 09:38:48 AM
A micro controller really is the easiest way to do this. I would use a PIC that has analog inputs (ADC ) and a UART. Axon and many other processors have this capability.
Title: Re: Sensor to computer
Post by: Hewhowalk on March 02, 2010, 11:12:59 AM
I would recommend using a Arduino Duemilanove. Extremly easy to use, and would work with most analog sensors.
Title: Re: Sensor to computer
Post by: zabuza™ on March 02, 2010, 12:26:22 PM
A micro controller really is the easiest way to do this. I would use a PIC that has analog inputs (ADC ) and a UART. Axon and many other processors have this capability.

true but i don't want to use a micro controller
Title: Re: Sensor to computer
Post by: zabuza™ on March 02, 2010, 12:35:50 PM
You need some sort of logic that is responsible for transmitting the data in a way that the computer can interpret (protocol). But I would recommend you to make it easy and buy a interfacecard of some sort with all tha logic and circuit ready-made. Google "the namn of your sensor +computer interface" and you shouldd find something useful.

iam using a photocell as my sensor. http://www.societyofrobots.com/schematics_photoresistor.shtml (http://www.societyofrobots.com/schematics_photoresistor.shtml)
Title: Re: Sensor to computer
Post by: chelmi on March 02, 2010, 12:57:21 PM
A micro controller really is the easiest way to do this. I would use a PIC that has analog inputs (ADC ) and a UART. Axon and many other processors have this capability.

true but i don't want to use a micro controller

Why?
Title: Re: Sensor to computer
Post by: waltr on March 02, 2010, 01:03:00 PM
A micro controller really is the easiest way to do this. I would use a PIC that has analog inputs (ADC ) and a UART. Axon and many other processors have this capability.

true but i don't want to use a micro controller

Ok, then the next option is a data acquisition card to plug into your PC's bus.
Here are some examples:
http://www.omega.com/literature/transactions/volume2/dataacq2.html (http://www.omega.com/literature/transactions/volume2/dataacq2.html)
http://www.dataq.com/news_releases/di410nr.htm (http://www.dataq.com/news_releases/di410nr.htm)
http://www.ni.com/dataacquisition/ (http://www.ni.com/dataacquisition/)

And this thread is asking the same question:
http://www.societyofrobots.com/robotforum/index.php?topic=10490.0 (http://www.societyofrobots.com/robotforum/index.php?topic=10490.0)
Title: Re: Sensor to computer
Post by: chelmi on March 02, 2010, 01:25:02 PM
Ok, then the next option is a data acquisition card to plug into your PC's bus.

You should mention the price of these babies (the cheapest is probably around 300 bucks), I'm pretty sure the OP will reconsider
the micro-controller solution. The phidget solution I quite expensive as well IMO.
Title: Re: Sensor to computer
Post by: waltr on March 02, 2010, 02:28:48 PM
Yep, but that's the alternative to using a microprocessor and programming it yourself.

Off the shelve solutions are faster to get running but do cost more. The OP wanted fast and not to build anything.

The Dataq device I linked to is only $24.95. Very cheap for what it does.
Title: Re: Sensor to computer
Post by: chelmi on March 02, 2010, 02:33:24 PM
The Dataq device I linked to is only $24.95. Very cheap for what it does.

I missed this one in your list! nice find.
Title: Re: Sensor to computer
Post by: Soeren on March 02, 2010, 04:01:11 PM
Hi,

iam using a photocell as my sensor. http://www.societyofrobots.com/schematics_photoresistor.shtml (http://www.societyofrobots.com/schematics_photoresistor.shtml)
You don't need an A/D-C if you just wanna detect if there's a certain amount of light or not (like in a line follower).
If you have a parallel port it could hook up to that and with a few extra components, a serial port could be used.
Title: Re: Sensor to computer
Post by: zabuza™ on March 02, 2010, 04:09:34 PM
Hi,

iam using a photocell as my sensor. http://www.societyofrobots.com/schematics_photoresistor.shtml (http://www.societyofrobots.com/schematics_photoresistor.shtml)
You don't need an A/D-C if you just wanna detect if there's a certain amount of light or not (like in a line follower).
If you have a parallel port it could hook up to that and with a few extra components, a serial port could be used.



just a serial port? surely u would need a/d converter to analyse the signal.

my idea is to send signals from the light sensors to the computer which sends signals by analyzing that data to motors to decide whether to move left right forward.









Title: Re: Sensor to computer
Post by: zabuza™ on March 02, 2010, 04:14:17 PM
A micro controller really is the easiest way to do this. I would use a PIC that has analog inputs (ADC ) and a UART. Axon and many other processors have this capability.

true but i don't want to use a micro controller

Ok, then the next option is a data acquisition card to plug into your PC's bus.
Here are some examples:
http://www.omega.com/literature/transactions/volume2/dataacq2.html (http://www.omega.com/literature/transactions/volume2/dataacq2.html)
http://www.dataq.com/news_releases/di410nr.htm (http://www.dataq.com/news_releases/di410nr.htm)
http://www.ni.com/dataacquisition/ (http://www.ni.com/dataacquisition/)

And this thread is asking the same question:
http://www.societyofrobots.com/robotforum/index.php?topic=10490.0 (http://www.societyofrobots.com/robotforum/index.php?topic=10490.0)

how would the wires physically fit into these daqs, would you have to modify the wires? so it would fit into their ports?
Title: Re: Sensor to computer
Post by: Soeren on March 02, 2010, 04:40:07 PM
Hi,

just a serial port? surely u would need a/d converter to analyse the signal.
Oh well, if you know better, then don't listen to me.
What is it you wanna get from analyzing it?


my idea is to send signals from the light sensors to the computer which sends signals by analyzing that data to motors to decide whether to move left right forward.
If you want to decide whether you're over a white or black area, you only need to see if you have more than so-and-so-much light reflectance - using an A/D-C for that is bordering the downright silly and it adds a huge amount of overhead.
Title: Re: Sensor to computer
Post by: zabuza™ on March 02, 2010, 06:17:15 PM
Hi,

just a serial port? surely u would need a/d converter to analyse the signal.
Oh well, if you know better, then don't listen to me.
What is it you wanna get from analyzing it?


my idea is to send signals from the light sensors to the computer which sends signals by analyzing that data to motors to decide whether to move left right forward.

xd iam just saying lol

If you want to decide whether you're over a white or black area, you only need to see if you have more than so-and-so-much light reflectance - using an A/D-C for that is bordering the downright silly and it adds a huge amount of overhead.


yeh tats pretty  much what i want to do. a line following robot following white line over black area without using a micro controller
Title: Re: Sensor to computer
Post by: Soeren on March 03, 2010, 07:08:21 PM
Hi,

yeh tats pretty  much what i want to do. a line following robot following white line over black area without using a micro controller
Then this circuit (http://That.Homepage.dk/PDF/LDR2PC.pdf) should do.
Title: Re: Sensor to computer
Post by: waltr on March 03, 2010, 09:36:48 PM
Or this one:
http://www.societyofrobots.com/member_tutorials/node/62 (http://www.societyofrobots.com/member_tutorials/node/62)
Title: Re: Sensor to computer
Post by: Soeren on March 04, 2010, 04:14:14 AM
Hi,

Or this one:
To stay within specs for the EIA/TIA-232, the signal has to stay within +/-3V minimum at the receiving end, with -V being "mark" or "1" and +V being "space" or "0".
How would you accomplish that with the circuit you point to?
Title: Re: Sensor to computer
Post by: waltr on March 04, 2010, 08:32:47 AM
Quote
a line following robot following white line over black area without using a micro controller

It'll do that. Scroll down to the second schematic.
Title: Re: Sensor to computer
Post by: Soeren on March 04, 2010, 08:41:16 AM
Hi,

Quote
a line following robot following white line over black area without using a micro controller

It'll do that. Scroll down to the second schematic.

You did see the
Quote
[...] i want to connect sensors to computer [...]
?
The circuit you point to is just an H-bridge with LDRs, no PC connection like the OP wanted.