View Full Version : Is Propeller suitable for this?

05-18-2008, 05:41 AM
I need a chip to control the sending of a rather strong electrical current to some terminals. Ideally, there would be 24 or more of these terminals, but I can build multiple of these units so it's not such a big problem, but it would start to be cost prohibitive any lower. The current I need to control is 12v @ 100+ amps, basically a car battery.

Obviously, the Propeller chip is not suited to this directly, but is there some way I can control it regardless? I need the following:
1) By default, each terminal will have a low current applied at something like 10mA and it will complete a circuit. There's a possibility that the terminal may not make a complete circuit, and I need to be able to detect whether or not a complete circuit is made, and I should be able to return a yes or no to the telnet.
2) On command, I need to be able to send a full current to one or multiple terminals at the same time.
3) I need to be able to use PropTCP at the same time as doing all of the above.

Forgive me if the answer is obvious, but I'm not all that familiar with microcontrollers, myself, only basic circuits. I'm hoping to learn through this project.

Ken Peterson
05-18-2008, 10:10 AM
Seems like if you drive a MOSFET with the Prop, and have that switch a heavy-duty relay, it should work. Sensing the small current might be tricky.

Perhaps if you could show some schematics, we might come up with some better ideas.


05-18-2008, 10:13 AM
it sounds like this is for a fireworks display.
I could be wrong

05-18-2008, 08:53 PM

i took a short look into the PropTCP-Object from the object-exchange (obex)

my knowledge about TCP is just that is is a connection-orientated protocol mostly used for transfering webpage-data.
i know almost nothing about inner details of the protocol except that there are datapackets with a header - not more.

So i have some questions to forummembers that are specialists about TCP/IP.

LuckyBambu wants to use the propeller with telnet.

Is telnet based on TCP/IP ?

To me the PropTCP-object seems to be just delivering the lowlevel-commands that where used to establish a TCP-connection
and manage the datatransfer. But i guess there are some more rules HOW to use these basic commands.

Does anybody know a link to a tutorial that explains that?
The object itself has no democode. Has anybody an examplecode for this?

How much effort is it to develop a software that is able to do datatransfer via TCP/IP

I mean something that gives an API as simple as

1.) PUB-Method connect(parameter IP-Adress)
everything else about details is done inside the method

2.) PUB-Method sendData(pointer to Data)
everything else about details is done inside the method

3.) PUB-Method ReceiveData(pointer to Data)
everything else about details is done inside the method

4.) disconnect

is this:
a.) very easy: 10 lines of code and everything is working based on PropTCP

b.) needs some programming-knowledge but then it will be done in 2-10 hours of testing/debugging

c.) quite complicated but with patience for debugging and passion for programming it can be done within 2-4 weeks

d.) oh my god if you are not an REAL EXPERT about TCP/IP keep away from trying this and buy any kind of TCP/IP to RS232 adapter



05-19-2008, 12:25 AM
You're pretty quick, FireHopper! Did you see my post elsewhere?

Ken, I'll try and draw up some schematics today if work can spare me the time, if not, I'll get them up soon.

Stefan, I'm going to be quite honest and say I don't know the inner workings of Propeller, however, looking at what PropTCP has done, I did notice that their Telnet implementation seems to be only able to process Basic. Maybe someone here has worked closely with it?

05-19-2008, 01:08 AM
I spent a large amount of time making the PropTCP Sockets code easy to use. The code on the objects exchange is just the low level driver that is released under a more open (MIT) license. The actual tcp stack code is released under GPL, so it has to be hosted elsewhere (proptcp.googlecode.com/ (http://proptcp.googlecode.com/)). Make sure you download the beta code.

There is an object named 'api_telnet_serial.spin' that provides an interface almost identical to FullDuplexSerial.spin. The only difference is you have to call a .connect(...) method or a .listen(...) method to establish the initial connection. It should be a drop in replacement for most apps that use FullDuplexSerial (take a look at the dongle basic example).

The stack takes a lot of time to write and debug, hence why there is so little documentation. The only documentation that exists is at code.google.com/p/proptcp/wiki/TelnetServer (http://code.google.com/p/proptcp/wiki/TelnetServer). An older api for the object can be seen at the bottom of that page.


Ken Peterson
05-19-2008, 01:25 AM
@StefanL38: Yes, Telnet works over TCP/IP as do many internet-related protocols including HTTP, FTP, POP, SMTP, etc.