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TandyMan100
February 5th, 2009, 05:48 AM
I'm looking for a good, under $50 DIY computer kit. I know about N8VEM, but the price for that came out at arount $150 at digikey. If anyone knows a cheap place to get parts PM me.

NobodyIsHere
February 5th, 2009, 08:47 AM
I'm looking for a good, under $50 DIY computer kit. I know about N8VEM, but the price for that came out at arount $150 at digikey. If anyone knows a cheap place to get parts PM me.

Hi! If you recall, James posted a parts list for less than $50 for the mini-N8VEM SBC. One could do similar for the regular N8VEM SBC using the "minimal" suggested parts list. I know the Jameco parts list is significantly less than the Digikey version. Neither parts list is $150 though.

http://n8vem-sbc.pbwiki.com/Least-expensive-but-still-functional-N8VEM-SBC

The part list you are referring to is a specific parts list a builder used for a particular system with specific requirements. It is not a general statement.

If cost is an issue, your time is better spent investigating other means of procuring the parts such as reuse of scrap electronics, electronics surplus stores, eBay, etc.

Thanks and have a nice day!

Andrew Lynch

carlsson
February 5th, 2009, 09:20 AM
I've begun to pick up bits here and there (read: various eBay sellers) for my N8VEMs, but will probably need to throw in an order at some overseas electronics reseller like Jameco. The hardest part so far to source appears to the 16550 or similar UART, whether it is required or not. I saw the minimum order value for international orders at Jameco is $30 which I easily will reach when ordering parts for five boards. Even with airmail shipping and possible 25% VAT added on arrival, it'd be cheaper than domestic suppliers.

channelmaniac
February 5th, 2009, 10:59 AM
Wow... a 16550 can be found on many cheap serial ports for the PC. I can pick those cards up for between $1 to $3 at the flea market.

If you want to build something old that needs odd chips like a 6532 RIOT (RAM, I/O, and Timer) then you should know that you can find those very close by. They are in every Atari 2600. ;)

RJ

carlsson
February 5th, 2009, 01:02 PM
I am a bit too lazy and unskilled (?) to desolder up to 5 x 40 pins without damaging anything.

jh1523
February 5th, 2009, 02:10 PM
You can get free samples of TL16C550 from Texas Instruments. You have to register with them, but it's a quick and painless process. I'm pretty sure they send samples overseas too. Or else find someone in the US to pick them up and ship them for you.

http://focus.ti.com/docs/prod/folders/print/tl16c550d.html

tezza
February 5th, 2009, 02:20 PM
I am a bit too lazy and unskilled (?) to desolder up to 5 x 40 pins without damaging anything.

Me too, but I have to say this "built-you-own-micro" project is having more and more appeal the longer I tinker around with (and understand) vintage hardware.

I'm probably not at the level of knowledge and skill required yet though.

Tez

Dr_Acula
February 5th, 2009, 09:26 PM
I got the N8VEM down to $50 by getting most of the parts from futurlec, and getting the "hard to get" ones on ebay. The last batch of 16C550s for instance were from the Czech Republic and were only a few dollars each. You can use either 16450 or 16550. I did leave out the real time clock though, but it isn't needed in my application with a wireless network because one board can act as timekeeper for all of them. Oh, and I included the board at $6 because that is what it cost on average for a batch, though one-off's are a bit more ($20). Life comes full circle - my very first computer was a CP/M one that my dad and I built together when I was a kid. (ok, he built it, and I watched). Search ebay every few days - bargains come up regularly, though you sometimes have to wait up to a month. When I see a bargain, I buy 10 and put them in a drawer. I'm still working through a batch of 2000 0.1uFs bought when I was a kid for 1c each.

NobodyIsHere
February 6th, 2009, 03:49 AM
Me too, but I have to say this "built-you-own-micro" project is having more and more appeal the longer I tinker around with (and understand) vintage hardware.

I'm probably not at the level of knowledge and skill required yet though.

Tez

Hi Tez! Thanks! If you can tell which is the hot end of a soldering iron you probably have enough basic skills to build one of the N8VEM SBCs. If not, this is a good place to start. Please don't sit on the sidelines watching when you could participate and have a lot of fun. I correspond by email with many builders of all skill levels from senior technical expert all the way to brand new hobbyists. However I think your best approach would be to just join the mailing list and ask questions. Tell us what you want to do and myself and the other builders will help you.

The N8VEM project is about home brew computing *not* kit building so it is a bit different than some of the other projects. Some builders have specific purposes in mind and things can get a lot more customized and "free form" in their implementations. That's great however there are also some tried and true methods to building your own system that are much lower risk and may be more suitable for the new hobbyist. The key to success with either approach is communication! Say what you want to do and ask the questions as to whether it will work or how to best approach it.

Certainly you and anyone else here are welcome to participate in the N8VEM project. I am very happy so many builders are having success and enjoying their systems. We've had many successes and a few problems along the way but to my knowledge every builder who has started building their own system has *eventually* gotten it working. I know of no "dead" systems out in the field and I poll the mailing list occasionally for builders to bring out their broken systems. Most have success on the first try, others it may take a little bit more work but so far everyone has gotten there. If and when a truly "dead" systems appears, I am willing and have offered several times to take it into my workshop to help. I'll find out the problem and fix it if it is possible/practical. So far no one has taken me up on the offer.

There are a few exceptional builders like James who is not only extremely talented in making new systems and adapting the existing parts for new purposes he is also extremely prolific in terms of system building. I recall James is literally pumping out working systems in *minutes* which boggles my mind because it takes longer than that for me to clear off my bench sufficiently to even start making something. His successes are exceptional and are probably not applicable to everybody but it does show what is possible with some effort and the willingness to give it a try.

Thanks and have a nice day!

Andrew Lynch

NobodyIsHere
February 6th, 2009, 03:59 AM
Wow... a 16550 can be found on many cheap serial ports for the PC. I can pick those cards up for between $1 to $3 at the flea market.

If you want to build something old that needs odd chips like a 6532 RIOT (RAM, I/O, and Timer) then you should know that you can find those very close by. They are in every Atari 2600. ;)

RJ

Hi! Thanks! That is an excellent point. I designed the N8VEM SBC with a couple of things in mind to keep costs low. The use of commonly available parts from electronic scrap such as the 16550 you mentioned can dramatically lower the cost of your build. The same applies to all the parts and the SBC uses PC style components in many areas because they are a good source of salvage components.

All the connectors, glue logic, passive components, etc are generic commonly available stuff. It can be ordered from suppliers, surplus stores, or desoldered out of old junk. Much of the SBC IO is optional and can be phased in as needed or not at all.

If you are willing you can even use parts from salvaged and/or "dead" PC or other electronic scrap. However in that case I recommend using sockets because you'll probably be doing some "swaptronics" or diagnosing parts to sort out the working from the broken. Reuse of old stuff is your friend in obtaining low cost materials.

Thanks and have a nice day!

Andrew Lynch

TandyMan100
February 6th, 2009, 05:40 AM
Hi Tez! Thanks! If you can tell which is the hot end of a soldering iron you probably have enough basic skills to build one of the N8VEM SBCs.

Crap. I once burned my whole hand by grabbing the wrong end of a 100amp soldering iron. Didn't hurt cause it just fryed the nerves.

tezza
February 6th, 2009, 12:38 PM
Hi Tez! Thanks! If you can tell which is the hot end of a soldering iron you probably have enough basic skills to build one of the N8VEM SBCs. If not, this is a good place to start. Please don't sit on the sidelines watching when you could participate and have a lot of fun. I correspond by email with many builders of all skill levels from senior technical expert all the way to brand new hobbyists. However I think your best approach would be to just join the mailing list and ask questions. Tell us what you want to do and myself and the other builders will help you.


Hi Andrew,

Thanks for the post. Your enthusiasm is compelling. I must admit when I started this hobby about 18 months ago, even contempating building an 8-bit micro would have been way off the wall. However I've learned that if I want to have working old micros there really is no alternative than to get down to the hardware level. For a non-techie like me, at first that was extremely daunting but the more I've tinkered and fixed, the more I've enjoyed this aspect of the hobby.

If I did get into a N8VEM project, it would be to learn. What is lacking and what I need is knowlege of how digital computers work at the IC/circuit level. I know more than I did, but I still can't join the dots. I've glanced at a few books but I really think "doing" is the best way to learn with something like this. Some day soon I'll need to bite the bullet and get some test equipment too.

One fear I have is that it will be far too MUCH fun. I do tend to become very focussed on project work I enjoy and I have to make a concious effort to balance that with relationships (family and friends) and my REAL work, which although not in electronics or IT, is of a professional nature and requires after-hours attention also. I struggle to maintain this balance sometimes but it's important that I do.

Anyway, I've had a good look at the website and getting involved in a N8VEM project is something I'll keep in mind. At the moment there are still a few hardware-related things I need to do with my present collection (...a few old apple drives that need fixing....some more cases which need de-yellowing...an Osborne with a capacitor that's buzzing somewhere...) to keep me going for a while. I also want to catalogue and catergorise what I've got for insurance purposes and figure out what software I have and what I might need as exemplars of the era/machine. Not as much fun as the hardware stuff but if I don't make a concious effort to do it, it won't get done. (-:

Tez

Terry Yager
February 6th, 2009, 01:03 PM
Crap. I once burned my whole hand by grabbing the wrong end of a 100amp soldering iron. Didn't hurt cause it just fryed the nerves.

Well, now that you've figgered that out, you should be ready to start the project.


--T