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CALCnet2.2 Hub Parts List

This is just a post for organization and info. The discussion topic and others are here: Part discussion and hub schematic announcement.

With the big discussion going on, I decided to create this post for the CALCnet2.2 hub part list. Basically, it lists the parts and where to get them.

Here they are! Smile

(1) Perfboard
(X) 2.5 mm sockets, stereo, solder to attach
Mouser
(2) 330-ohm resistors, 1/4 watt
(2) ~2.1V LEDs of your choice
(4) 10K-ohm resistors, 1/4 watt
(2) 1K-ohm resistors, 1/4 watt
(4) 2N3904 NPN bipolar transistors
(-) +5V supply
==> AA battery
-------->

And as always, you can get most (if not all) of these parts at your neighborhood friendly RadioShack (??), or your local electronic components store.

Schematic:


Alternate Schematic:


Prototype:


(Images from http://www.cemetech.net/forum/viewtopic.php?t=5064)

Feel free to add on! (Edit it if you are an admin - if not, just post the suggestion in the part discussion topic.)

Strangely enough, this thing looks so much like the OTZ80 topics...
Awesome! I see that you've chosen to go with the 4x NPN design rather than the proposed 2x PNP alternative that Ben suggested?
KermMartian wrote:
Awesome! I see that you've chosen to go with the 4x NPN design rather than the proposed 2x PNP alternative that Ben suggested?


I'd love to go with the 2x PNP transistor alternative... but I suck at prototyping as-is (I used to do this kind of stuff, but you forget after a while Razz). If you could draft up another schematic for me to use, I can update the topic with the new parts update and schematic. Smile Sometime this week, perhaps?
alberthrocks wrote:
KermMartian wrote:
Awesome! I see that you've chosen to go with the 4x NPN design rather than the proposed 2x PNP alternative that Ben suggested?


I'd love to go with the 2x PNP transistor alternative... but I suck at prototyping as-is (I used to do this kind of stuff, but you forget after a while Razz). If you could draft up another schematic for me to use, I can update the topic with the new parts update and schematic. Smile Sometime this week, perhaps?
Sure, I'll try to get to it. Smile I'm trying to source a few more calculators from eBay so I can continue to expand my network prototoype.
In an earlier thread you mention that there is no need for external power. Is the +5V just for the LEDs? If not, will 4.5V do?
merthsoft wrote:
In an earlier thread you mention that there is no need for external power. Is the +5V just for the LEDs? If not, will 4.5V do?
Yup, the only power necessary is for the link activity LEDs. If you're building a hub with no LEDs, no power is necessary at all. I would think that 4.5V would be fine for the LEDs.
In that case I would imagine 1.5 volts would be plenty!
merthsoft wrote:
In that case I would imagine 1.5 volts would be plenty!
No. The base-emitter turnon threshold of the transistors is 0.7V, the minimum voltage across the LEDs is 2.1V, assuming about 4mA of current through each, you drop at least a volt on the resistor for each, so even 3V is pushing towards very dim LEDs.
Hmm, well, ok. I've got 3xAA holders out the wazoo so I'll just use those, then. Also, I'm still not 100% sure on how to set everything up. For instance, how do I hook the calcs up, etc.? I'm not seeing that by your schematic.
merthsoft wrote:
Hmm, well, ok. I've got 3xAA holders out the wazoo so I'll just use those, then. Also, I'm still not 100% sure on how to set everything up. For instance, how do I hook the calcs up, etc.? I'm not seeing that by your schematic.
That's for two reasons, first that that schematic is just for the link activity LEDs, and second that it's so trivial I didn't think it needed mentioning. You just connect all the base/grounds of all the sockets or plugs together, you connect all the tips together, and you connect all the rings together.
It needs mentioning because there's no way to know it's so trivial without you saying so!
And thanks. That is simple.
merthsoft wrote:
It needs mentioning because there's no way to know it's so trivial without you saying so!
And thanks. That is simple.
Sure, glad to hear it. I've also edited Alberthro's original post starting this topic to include the alternate PNP schematic.
Ok, so I've got it set up! Here are some pics. Let me know if something looks off:


The amber light is just a power light. And at the time of this writing, I've ordered a bunch of calc<->calc cables, and another calc so I can test it. Should happen sometime next week.
That looks completely epic to me! Have you had a chance to give it a test yet? Even if you have a single calculator and link cable, you can still either use the TI-OS to try to transmit something, or run the NetPong intro screen, and both will try to probe the network and hence trigger both LEDs.
Unfortunately I don't have a calc to calc cable right now. I have plugged it into my silver link, though, and the lights turn on as it plugs in, at least. And when I run TI DeviceExplorer, they strobe slowly back and forth.
merthsoft wrote:
Unfortunately I don't have a calc to calc cable right now. I have plugged it into my silver link, though, and the lights turn on as it plugs in, at least. And when I run TI DeviceExplorer, they strobe slowly back and forth.
That's good to hear. Just the fact that the LEDs are off with nothing connected and flickered on with a connection means that that untested schematic I posted is indeed correct (as, of course, I had assumed Wink). So what's next, an enclosure?

Edit: And I just noticed that you color-coded Clock, Data, and Ground! Nice job.
KermMartian wrote:
So what's next, an enclosure?

Edit: And I just noticed that you color-coded Clock, Data, and Ground! Nice job.
An enclosure eventually. For now I'll be working on software until I get some calcs to test with. As for the color-coding, I know what I'm doing Wink. The one thing that isn't consistent are the orange jumpers coming from the HI into the transistors, they're orange instead of red. This is because the little red jumpers I have are too little, and I didn't feel like cutting up some at the time.
That makes perfect sense. You ended up getting the jumper kit from RadioShack as well? Would you mind enumerating your purchases from RS and their associated prices for the general edification of other people looking to build CALCnet devices?
I tossed the receipt, and it actually took two different radio shacks, but I got the PNPs in a packet of 15, and I got the 2.5mm (3/32) jacks in packets of 2 (there were only two packets, or I would've bought more). I also bought a jumper kit. Everything else I already had left over from my senior research. The total cost for everything was $15.50 (after tax), which is a little high, but to be expected from Radio Shack. It turns out my roommate has plenty of PNPs that I could've used, but oh well.
Just a quick question: how are the lights supposed to blink?
Are they router style (all lights on, blinks in random pattern when link activity passes through), or do they just turn on and blink when they sense activity?
  
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