Attiny85 PCB Rev B Preview

Moving along with some revisions to my first two PCB designs, I’m working on some changes to the Attiny85 programmer & breakout board. The following is sort of a mock up as I’m just trying to figure out the form of the board right now.

1So the first thing that you’ll notice is that it’s not a square. It has rounded corners this time! But really, the form of the board has changed a lot. I want to design it so that you can break off the programming area when you’re ready to use the board in your project. The benefit to that is the breakout takes up less space in your project… and it’s kind of neat, IMO.

Something else I did new this time is that this board is actually completely manually routed. I’ve relied mostly on the autorouter up to this point. The Design Rule Check isn’t coming up with any errors so that’s positive.

Some parts should be coming in any day now that will let me assemble and sell the first version of the Attiny85 Programmer & Breakout on eBay, along with the other things I’m currently selling. People buying them will show me how much interest there is in this kind of thing. I really like this design I’m going for so hopefully there’s enough interest to get the new version manufactured when it’s ready (Rev A buyers may get a discount). Stay tuned! Thanks for visiting!

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74HC595 Breakout PCB Small Update

In my previous post, I talked about how I assembled my first PCB that came in and that the Attiny85 programmer/breakout design works great. Unfortunately, the 74HC595 shift register breakout does not. I haven’t found the source of the problem yet but I wanted to leave a few notes on what I’ve looked at so far.

I went through the schematic again in Eagle and it looks fine. All of the connections appear to be made properly. I do not think the circuit design is the problem.

Some ideas I’ve had on what could be wrong are burnt shift registers during soldering, programming errors, or something wrong with the traces (shorted or opened). I do not believe the shift registers are burned out, nor do I believe there is an issue with programming. If I disconnect Vcc and Ground and poke both with the Ground wire, the pattern will run once and then stop. I’ve also noticed that when I touch an area on the back of the board, all of the LEDs will latch on. That makes me believe there’s an issue with a trace somewhere.

I plan on soldering another shift register board later today, reusing the parts I used on this board. I’ll try with just one shift register first and then add a second one if it works. I’ll post the results when that’s done!

1st PCB assembled!

Earlier today, I received my first PCBs in the mail. I assembled one of the boards so I can finally see what they look like put together and to see if they work.IMG_20140805_165250~2The size of the boards are actually smaller than I envisioned them. I was worried about the text being too small and/or unreadable but even the smallest text on the board is perfectly fine.
IMG_20140805_203120The green LED is a power indicator. This is what it looks like connected to an Arduino Uno to program the Attiny85 microcontroller. It worked just fine after setting up the Uno for programming the Attiny85. Those extra steps are the reason I printed a URL on the board so I have a place to put the instructions if and when the boards end up in the hands of someone else.
IMG_20140805_203727I was incredibly happy to see that the breakout side also works.

Unfortunately, at this point, the 74HC595 shift register breakout doesn’t work. Some poking around causes weird effects. I’ll spend some time debugging it tomorrow. I really hope it’s just this board and not all the others too. We’ll see what happens.

Thanks for reading! As always, stay tuned for more. I have more packages incoming for more fun!

My 1st PCBs in the house!

The boards that I designed a while ago have arrived! See the other post I just made about the service from DirtyPCBs where these are from.4At this point, I’m just excited to show off the PCBs to you. I haven’t actually soldered anything yet because I’m still making observations. One thing I’m extremely relieved about is the slot in between the two designs. I was asking around and never really got a firm answer from anyone so I just tried what I thought made sense and it turns out it does!
5The slot left tabs small enough that were easy to break just by bending it over a straight edge of a table.

Thanks so much for reading! Stay tuned for more!

My first attempt at Eagle

I never have things manufactured custom for my projects. It’s all put together using my own two hands. I haven’t had any good projects on deck for a while and I wanted to learn something new so I ended up with some motivation to try and pick up Eagle. I used it just once in college. I tried several times on my own after but I never took it seriously so it never went anywhere. Yesterday I sat through a YouTube tutorial series (Here’s Part 1) that guided me through it. I understand a lot more about Eagle than I ever have.

With the tutorial complete, I wanted to make my own design. I wanted it to be a revisit of a circuit I had done before so I have a good understanding of the circuit, and also something practical since I’d probably end up with 10 of these if and when I get them manufactured. In the end, I chose to redo the Attiny85 programmer shield I made a while back. It won’t be a shield that sits on top of the Arduino but it will still make programming easy and will break out the pins so I don’t have to keep looking it up.

schematicThe schematic is kind of a mess but I think it’s all good. I’ll need to take a non-lazy final look through it before I finalize any PCB layout.pcbThis is what it looks like at the time of this post. Things are bound to change though. I literally just added the Power On LED and resistor (R) because I had that space left. I’m a little skeptical this is the right size for a 5cmx5cm board because it seems like I’ve fit so much on it…3dI’ve been looking at different gerber file viewers and I came across ZofzPCB which renders the board in 3D. It’s pretty cool to look at since I have yet to have a PCB manufactured.  I tried a few normal 3D gerber viewers and my favorite is ViewMate. One thing that viewers made me realize is that I had to use vector fonts because the default font would show up bigger in the viewer and trail off of the board. It did not appear like this in Eagle so I learned the importance of checking it in a viewer.

Once I send it off to be manufactured, I’ll post up all of the files. Thanks for reading!