kenemon 29 Posted September 2, 2011 Share Posted September 2, 2011 Hi All, I broke down and had some PCB's made for the LS Research TiWi-R2 module. I dont see myself using all ten, so let me know if you are interested in some kind of deal. The chip itself is pretty cool. It has 802.11 and Bluetooth onboard. Just a little too small to solder wires to :!!!: http://www.lsr.com/products/radio_modules/802.11_BGN_BT/tiwi-r2.aspx Nothing complicated this time, just your basic breadboard and butter pin access. Quote Link to post Share on other sites
HylianSavior 37 Posted September 2, 2011 Share Posted September 2, 2011 I am interested in purchasing one. Quote Link to post Share on other sites
kenemon 29 Posted September 2, 2011 Author Share Posted September 2, 2011 I will let anyone who replies know when they arrive. Thanks for your interest. Quote Link to post Share on other sites
AaronInSpace 4 Posted September 25, 2011 Share Posted September 25, 2011 I'd take one off your hands too, please. Quote Link to post Share on other sites
kenemon 29 Posted September 26, 2011 Author Share Posted September 26, 2011 I finally got the boards. They appeared beautiful, and i received two extra. I immediately noticed that the spacing was off for the module. I verified my Gerbers, and tried to make it work anyhow. Managed to fry a hell of a nice module due to my frustration. It seems like something happened in translation. When I checked the spacing with some standard .1in headers, they also had some drift. I contacted LSR, and they proclaim the footprint is correct. I feel bad that I failed on this one. I am going to try to rework the board, and get a new mod when I stop crying. I think if I make the pads a little smaller of ovals it would work fine. Any ideas what went wrong? Quote Link to post Share on other sites
bluehash 1,581 Posted September 26, 2011 Share Posted September 26, 2011 Learn from your mistake. For a first job, it come out well. kenemon 1 Quote Link to post Share on other sites
zeke 693 Posted September 27, 2011 Share Posted September 27, 2011 Don't feel bad! Making mistakes is perfectly normal and they are perfectly acceptable. Anyone who criticizes you for making a mistake deserves to be knocked to the ground! Making mistakes means that you're that much closer to achieving your goal! The first thing that I would recommend is that you go to your local tool store (Harbour Freight, Princess Auto) and buy a set of digital calipers. Use them to measure all the important mechanical dimensions of your parts. Compare them to the datasheet. If they agree then create the component footprint yourself. When it comes to datasheets, they LIE sometimes. Engineers are not known for their love of documentation. They hope no one notices. The second thing to do would be to have someone you trust to take a look at your schematic and layout. Ask them to be objective and act as an Editor. Give them permission to question your design decisions. They just might save your bacon with a simple question "Does this look right?" In the future, I would be willing to take a look at the pcb layout and offer comments if you think you might benefit from that. And that offer stands for anyone else doing pcb layouts. nuetron and kenemon 2 Quote Link to post Share on other sites
kenemon 29 Posted September 27, 2011 Author Share Posted September 27, 2011 Thanks Zeke, I appreciate the support. I will definitely let you know next time before i leap. I have been putting off the caliper, but I am sure it will save in the long run. KB Quote Link to post Share on other sites
RobG 1,892 Posted September 27, 2011 Share Posted September 27, 2011 What did you use to create your layout? I bet it's the rounding error when converting between mm and inches. Quote Link to post Share on other sites
kenemon 29 Posted September 27, 2011 Author Share Posted September 27, 2011 I used designspark. When I inquired about the spans, they reported .89 and 2.63mm where I measure 1.00 and 2.5mm on my design. You would think that a rounding error would have been considered by the programmer way in the beginning.... Quote Link to post Share on other sites
kenemon 29 Posted September 27, 2011 Author Share Posted September 27, 2011 I used designspark. When I inquired about the spans, they reported .89 and 2.63mm where I measure 1.00 and 2.5mm on my design. You would think that a rounding error would have been considered by the programmer way in the beginning.... update: when I started a discourse with Seeed they were as helpful as humanly possible. Unfortunately, it was my fault ($ :cry: $), It appears I was using mil ruler at the start and something was lost in translation. The design matched my numbers, but gerber files had inappropriate scaling. Quote Link to post Share on other sites
kenemon 29 Posted October 19, 2011 Author Share Posted October 19, 2011 Hey Zeke, I finally worked up the beans to get a new wifi mod and have been working on a new board. Would you mind giving it a lookover? Thanks. KB I changed their elaborate heatsink to work with two layers, I dont think my ideas are going to heat up the board much... Quote Link to post Share on other sites
zeke 693 Posted October 20, 2011 Share Posted October 20, 2011 Ah nuts. I'm 200 miles away from home and all I have is my iPod touch. It's useless for checking layouts. I'll be back home tomorrow and I'll check it out then. Hopefully Designspark is easy to work with. I can also work with gerber files too. Actually that might be better. Can you post a link to them for me? We'll make sure this is right. kenemon 1 Quote Link to post Share on other sites
kenemon 29 Posted October 20, 2011 Author Share Posted October 20, 2011 Thanks Zeke, That would be great. I linked the gerber files in the previous message. KB Quote Link to post Share on other sites
zeke 693 Posted October 21, 2011 Share Posted October 21, 2011 All righty then. The footprint for the TiWi module matches the data sheet (pg 28) exactly. Good job! The only gotcha that I can see is the ground plane. On page 28 of the datasheet, Layout Notes #1 & #2 are the gotchas. Gotcha #1: The manufacturer is expecting the user to create a 4 layer pcb where the second layer is a ground plane. I believe you're making a 2 layer board. Resolution: You create a ground pour on your bottom layer underneath the device on the top and the bottom layers. Gotcha #2: The manufacturer is expecting the user to create a solid ground connection between top, bottom and inner layer 2 (GND) using Ample Vias. Resolution: You add in zillions of vias to connect the top and the bottom ground pours. Pick a standard sized via. Datasheet says 0.4mm diameter. Space them 1mm apart in a grid pattern. That's going to be a lot of vias but don't sweat it. If you ground the H. E. double hockey sticks out of the board then it will work well. Does that help? kenemon 1 Quote Link to post Share on other sites
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