Project Logs

Collapse

• Post LayerOne

  charliex • 06/01/2014 at 16:48 • 0 comments

  Well layerone has been and gone, and apparently it was great, i don't know since i was in the back room getting a couple of hours sleep coding, while the others around me soldered boards together. I'm usually one to write up logs as they happen or just after, but this was a serious drain ( as well as the fact i have to delveop multiple hardware systems at work by siggraph), we're still building out badges. 

  Did the board work ?, yes it did, I missed one mosi line to the OLED so that was a kynar fix, but beyond that so far everything has worked, we read tags.

  terribly grainy video

  The HF/LF add on.

• Finally all the PCB's in one place

  charliex • 05/21/2014 at 17:07 • 0 comments

  left side, LF antenna, middle HF antenna, right badge board, top combined HF/LF antenna.

  The late nights/early mornings have started. The HF antenna is marginal right now so we just need to get the right caps/inductors added, but it did read. The LF of the combined card is working fine, HF side needs more inductors. RF is black magic.

  There are tables strewn with parts as the kits are made, and we inventory everything for that last order for the bits that are missing or forgotten.

  Hopefully tonight we'll get board built out.. Unfortunately our big laser is still in bits after the move, and the bits for the CNC mill aren't with the CNC..

• Badge PCB's Arrived

  charliex • 05/20/2014 at 18:44 • 0 comments

  After delays, e-test errors, shipping problems, wild fires and 6 revisions. These completely untested hopefully 4 layer PCBs have arrived. I'm probably just being paranoid but they sure look like 2 layer.

  Also Arrow decided that I didn't want overnight shipping for the CPU's even though we had a conversation about ground vs air and i didn't want to take the risk, so they chose to "upgrade" me to ground shipping from Reno, NV. Shipped last Friday, haven't yet arrived..

  Thanks Arrow ! One of our family works at Arrow too, tsk!

  Updated: The man from Extech says "Beep beep beep", coincidentally this is only piece of test equipment I have with me, and I saw it the other day thinking it was something else, then thinking whenever would i need that.. Few days later came in very handy..

  Let the builds begin!

• fedex and wildfires

  charliex • 05/19/2014 at 17:47 • 0 comments

  It's wildfire season, but Fedex managed to get our boards from Malaysia to us in good time, unfortunately there was a cock up in the ordering department and they shipped to the billing address, we'd left there about 15 minutes before they showed up with the package. So I signed for it online and it'll be left at the door tomorrow. I don't want to reroute it or go to the distribution centre, since Murphy's Law might kick in. The actual badges should arrive tomorrow at the right address, I did go and check. I also looked back on my order and it listed the shipping/billing address clearly four times, but they use paypal and paypal helpfully sends out another address.

  Also Verical finally got back to me about my locked out, currently unknown password account, three days after I figured out how to get into myself and place the order. Same with Arrow, gave up and called in, have yet to see a tracking ID from them though.  I have to say Digikey always impresses me on speed, sometimes they're just too fast, I've ordered something then 10 minutes later thought about another part to add, and too late its in the warehouse. Arrow/Verical do tend have some parts a lot cheaper though, often its parity with mouser/digikey but farnell/element14/arrow and verical sometimes have really good deals. Especially element14's part sales. 

  Allied are good too, Allied for Europeans like myself, are RS Components, my uncle used to work for them in the UK and he'd get me the giant paper catalogue that you normally needed to be a proper actual business at the time to get, it was the greatest thing ever. Now the paper books are mostly doorstops if they even exist. RS was this amazing thing in the sky that had all these neat impossibly expensive things, so Maplins it'd usually be. RS is Radio Spares, not tied to Radio Shack, or Tandy as it was in the UK.

  Anyway we placed the hopefully final parts order from Digikey, Arrow and Verical. Parts we'd started off with had gone out of production or just not available, so a last minute late night dash to find replacements. Luckily it was just the MCP100T reset controller, so that is an easy move to the MCP800 series, the 16 MHz 2-SMD Xtal had a newer version, and a couple of other parts.  I added each of the new parts in as OEM_ALT DIGIKEY_ALT etc in the attributes and checked in a new svn revision for each, that way we can see them in the log's clearly.

  On Saturday i swapped out the STM32F1 chip for the STM32F4 on a 95% built prototype board,  rather than scratch build a new one on the quick turn PCB's i'd gotten. All i had to do was carefully cut a couple of traces and put two 2.2uF caps on, i used a microscope and small knife to score away the traces. It's tougher than it seems, there are tools i've seen specific to that task, i've tried drills and snips etc, but this one was right a the leg of the IC.

  After cutting away the traces I added the two caps the STM32F4 needs, and some kynar wire, and booted it up, the JTAG didn't see it at first,  but seemed to be mostly an issue with the software side of things. A few unplugs and it worked fine.

  It ain't pretty but it worked. The blue kynar wires are going to the caps. The Red wire is because we hadn't built out the battery charger circuit on this board, since we weren't sure about the values, it was built on a separate PCB

  This is the battery test board, on the other side is a 5mm blue LED, we just let it charge and discharge daily. I'll try to add more details about this one, mmca is the one that put the circuit together, I believe its an iteration of the blinky ball. The chips used for the battery controller though might be getting tough to source, so might need to be revised in future.

  Here is krs putting something on something, I don't recall what it is, but the blinding light from the scope is obscuring it

  I think it was the antenna boards. For these we had to match the capacitors to get the best voltage at 125khz, so i pulled off the ones from...

  Read more »

• anticipation, neoden, parts ordering, BOM.

  charliex • 05/17/2014 at 00:10 • 0 comments

  we're still waiting on a tracking number for the PCB's, the conference is in just over a week!  and i can't finish the code til we get the first one made... oddly enough this hasn't been the closest we've cut it, but its getting there.

  since there is a huge disparity  between vendors ( and findchips.com is so useful ) i've been trying to get parts from arrow for a while, they have my old address in there and only they can update it, i started requested that three weeks ago  (and yes thanks Arko, i did try calling ) . Today I  gave up and asked them to let me order it over the phone, of course the parts weren't in stock, even though they show up as in stock .

  They found them on cut tape vs reel, and gave me reel pricing, so that was nice. I also picked up some SAM7 32KB's for people who just want a basic badge that does something. As with the last few L1's i'll probably spend most of the con writing code or building badges, my neoden TM220A is reeled up ready to go, ( don't buy the 220, get the 240 i didn't follow my own rule on this and it definitely wasn't a good idea.

  Neoden are coming out with a new model as well, i'm guessing around June, but I'm also guessing it'd be a higher price, if you do buy from Neoden, don't accept the first quote, they'll drop the price.

  I like the Neoden, its pretty straight forward, we have our Juki conversion as well, but that's at Null Space again and not in my garage, and its unlikely we'll get it set up in time, the TM220A I keep at home.

  One of the problems I find we run into is that its easy to get into the mindset of buying parts from places like DIgikey who'll ship out a few hours after you order sometimes, so you think , yeah plenty of time!  Since we're rev'ing the design as we go its been tough to order ahead, parts get forgotten about,. We use Google Docs Spreadsheet with a modified version of bom-xs.ulp to handle parts and ordering.

  We set attributes in the schematic for each PART

  MPN/PARTNO manufacturer part number (some BOM scripts use others)

  DIGIKEY digikey part number, i'm going to change this next revision, and add DIGIKEY-REEL or something to specify reels etc for Jellybean parts.

  OEM manufacturer

  Here's an example of a part

  I fill in the part number from mouser/newark etc ( you can see here MF is set to the wrong thing!)

  It can also be exported to a database that you can share with others.

  bom-xs.ulp creates an order, or parts list and then we can paste it into digikey, or arrows BOM managers and they'll quote it, as well as show parts that are duplicated or not available, expect that a lot!

  Shown by Values

  Also useful for handing kits, BOMs and just general checking. Document and update the attributes as you go along, consider ALT's as well. We've gone through a couple of BOM managers, but bom-xs has worked out the best for me so far, i even wrote a digikey scraper that pulled in parts to a local SQL database to get better matching than the website offers. But I didn't have time to finish it.

  It can also query Digikey for pricing, but it needs some love on that side of things.

  I've thought about trying to get this working with findchips to get the lowest price/quantity from whomever, but it isn't setup for that yet. I'm just glas it works as well as it does at the moment.

  If you take enough care with the attributes and parts, you can pass on the list to other people, the more you do upfront and just as important, getting people to use computers to do the work, versus how we typically do it and end up doing all the slug work ourselves.  Eagle does  hard code some values into the part when you make it, so think about that, like a CPU that can be 32/128/256 variants, use the variants, all it does is change the name/value.

  I wish eagle had more interactivity when its in a ULP, typically changes you do in the ULP , you generate a script, and run that on exit of the script, I also wish it was non blocking so i could keep working in Eagle while the BOM is open.

  Another...

  Read more »

• Oh yeah I forgot.

  charliex • 05/12/2014 at 16:51 • 0 comments

  Not only does this badge have an FPGA, but there is also a breakout and chip pads for a BitFury BTC ASIC

• LF Antennas arrived from PCB house

  charliex • 05/12/2014 at 16:43 • 0 comments

  Just took them out of the box, need to test them and see if they've worked, RF is black magic.

  The other boards are also out for manufacturing. They should be here this week , hopefully since we have to pre-build a bunch!

• added a larger OLED

  charliex • 03/05/2014 at 17:58 • 3 comments

  Terrible cell phone pic, the 1.3" 128x96 OLED SSD1306 is a direct drop in replacement for the 0.96". 

  Though it is $5.00 vs $2.57 , I do like the bigger display . I'll hopefully take a better pic of it, certainly couldn't take  a worse one. It still has the plastic cover on it.

  Compared to the 0.96" 

  These are remarkably easy to solder and desolder, lay a small line of paste over the pads and drag solder, then run the iron parallel to the edge connectors for each pad to clear up any bridges or excess solder , don't go nuts on the amount of paste.

  To desolder all i did was gently lift one side at the right of the connect and slowly move the iron right to left over the pads and it just lifts off. i am using leaded solder.

• timelapse of power and arm/fpga soldering up

  charliex • 03/03/2014 at 03:56 • 3 comments

  we did a timelapse of arko hand assembling the first couple of rev3 boards since we can't pick and place them and test as we go along.

• power....

  charliex • 03/02/2014 at 19:18 • 0 comments

  Arko started putting the rev3 board together last night, we usually build the power section first and measure how it looks, make sure none of the power is shorted in the PCB ( it happens). This board has one always on regulator, its a 3.3V LDO  that one didn't show up, the 5V in from the USB was there.  But nothing else, hmm. did we not jumper the battery boost ICs since they're not yet populated ? Nope that was ok... I had the schematic open and sure enough... I see a problem, i highlight it on  the board image in Eagle and Arko spots it next, we have friends over at the time and they're looking at us wondering we w're going 'uh oh' 

  Funny how everything looks obvious when you're looking for a fault ( the airwire I added after we found it, it just hasn't been routed yet, which in itself is also going to be a bit of a hassle, since technically unless i route it, its not a 2 layer board! )

  The post boost 5V line isn't connected to the VDD, and i'm also thinking why does 5V still exist as a name ?

  Well the reason is simple, and its caught me out a few times , even during this board.

  I'd renamed 5V to VDD, but I did not change the "Change Name of" option from "this Segment" to "all Segments on all Sheets", simple as that. Once that OK button is clicked i severed the link between VDD and 5V  and the board no longer had power, even though we all go over it a few times, no one spotted it. The worst part of this is that it casts doubt everywhere else, and maybe that signal that runs all over the place that just has a default eagle name of n$7 has been severed and it'll be really hard to spot. So i've never liked that particular option, Eagle doesn't remember what I last choose and there probably is a good reason they choose  this way.

  So we jumper from the VUSB in to a big pad of one of the caps and we're off, the 3.3V turns up, current draw looks fine.

  Tektronics software is awful by the way, i will tell you this boy, capturing a screenshot across the USB instead of the actual signal ? Madness, there is more data in the crappy image than there is in the waveform, i just don't understand the point of a screen capture transfer.. The best part is that on the scope if you use the save to disk option, it also captures the save to disk menu instead of the say for instance, much more useful measure screen. Of course you can use the other tek/visa software to download the waveforms instead, it'll install 10 or so background services that run all the time, and chew up a bunch of resources, then it'll transfer waveforms  at the speed of mud, so much "scientific/test instrument" software is as clunky as this. The waveform Data Capture mode is equally slow but provides a much better image, but also much less data, wheres the useful measurements the scope provides, no axis levels, and for some reason a large white border? Wouldn't I rather have that are as screen real estate for the graph (or axis labels/measurements). again the other software does all this, but its just a royal PITA to use properly.

  
  

  So screenshot has more information, crappier waveform and 1980's CGA bitmap stylings, waveform has less helper data, and a much nicer rendering with a giant border. Open Choice Desktop, thats my choice, poor processing vs a dozen installed services that do nothing 95% of the time my computer is running, it's become a real problem that software relies on background services that always run, so you just get bogged down with every updater app, or licensing daemon, its just not needed and poor design style.

  Anyway, the FPGA and ARM are added next, ARM doesn't power up, this time I know what it is since we did this on the last board, there is a ferrite on VDDA that is missing and the ARM won't do anything without it, sure enough add it and the JTAG boots up and sees the chip, i flash in the rev2 software since the power on line is still the same and the FPGA jumps into life, it doesn't over heat so that's a good start.

  I add a define...

  Read more »

View all 11 project logs