New products you already know

Yesterday I released two “new” products. They are both revisions of projects you’ve seen on the blog before.

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They are both the second revisions. They are the Attiny85 Programmer & Breakout Board and the Atmega328p Breakout Board. They’ve both been completely redesigned (ie. manually routed this time) with new features!

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Remember this clunky old thing? This is the original Attiny85 Programmer & Breakout. I really wanted to go for something more compact and breadboardable.

1I really like how the new one turned out because my measurements worked out! The board can sit on the edge of an 830-point breadboard so that the programming and breakout pins fit into the prototyping area, with the input power pins fitting nicely on the side power rails.

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To the right is the old Atmega328p Breakout. There’s not much change to the way it looks but the new board does have a few nice changes to it.

1The new board now breaks out the reset pin so that you can add an external reset.

Both boards now have LED power indicators, SMD components, and 6-pin ISP headers.

Head on over to my Tindie store to check them out!

So that’s what’s been going on. I’ve been meaning to do a new light show (possibly sans fountains for now). I mostly just want to use my new shift register boards with the PWM control it now allows… Stay tuned and thanks for visiting!

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Eye on the power

I added in the battery level code from https://code.google.com/p/tinkerit/wiki/SecretVoltmeter into my ESP8266 program and it works like a charm. The code uses a reference voltage in the Atmega328p microcontroller to get a reading of Vcc going into the ATmega328p. For the ESP8266 project, that would be the 5v output of the AMS1117 board. In my testing with the dead-ish battery yesterday, I found that the system started to fall apart once it dropped below 5v. The LCD backlight would start flickering and the sending of data seemed to fail more often.

I already have the system sending me emails if it gets bad values from the DHT22 sensor or the ESP8266 fails at sending to both ThingSpeak and my webhost in the same cycle. It was easy enough to add a little more code so it would send me emails at certain voltage levels. I’ve got it sending emails to me when it drops to 5, 4.8, 4.6, and 4.4 volts.

Screenshot_2015-01-24-00-02-03I got this email when I retried the battery for the third time after bringing it in from outside in yesterdays outdoor trial. If I give the battery a rest, it’ll be able to power up the system again but it’ll die after a short period. The lowest threshold email I got was for 4.6v before the battery died again.

I don’t expect this project to go battery powered again but this is definitely something I’m glad I found and I hope it finds a place in other projects.

At this point, I feel like the project is over. It’s been a great learning experience working with two programming languages, my custom PCBs, and seeing the community that has gathered around the ESP8266. It doesn’t have to be over though… Solar power, anyone? Perhaps in the future.

Like I mentioned a couple posts ago, I have other projects coming up, including some experiments with some RF transmitter and receivers, and my custom shift register PCBs that should come in next week if the postal service is consistent with the last two times I ordered from Dirty PCBs.

 Thanks for reading!

ATmega328p Breakout Test Results

In my last post, I talked about the tests I did with the AMS1117 Board. Now it’s over to the ATmega328p Breakout Board. The testing was a lot simpler, and included the AMS1117 board.IMG_20140919_121331This was it. The test was just to run a sketch on the ATmega328 microcontroller, uploaded using an Arduino Uno. The sketch was some patterns that used all 17 outputs (the 11 (not using RX or TX), plus the analog in pins used as digital outputs). The chasing patterns made sure that that the pads were connected in order. Here’s a video:

IMG_20140919_154612I used my multimeter to do some other tests. I tested the other pads on the board (RX/0, TX/1, and the Vcc and GND pads) with the multimeter. I also measured the curent flowing between the AMS1117 and the ATmega328 board. The reading in the picture above is from when all of the LEDs are on.

One thing I realized is that the 1A fuse for the uA and mA setting on my multimeter is blown. I went looking for them and the cheapest I can find is a 20 pack for ~$5… The A setting works just fine so I can live with it. The fuse on the A setting is 10A so it should last a while and would be the one I’m more willing to replace if it does blow someday.

Anyways, thanks for reading! I’m still planning out some projects so stay tuned!

New PCBs! (AMS1117 regulators & ATmega328p breakout)

I’m excited to finally have my second round of PCBs here! The designs are an AMS1117 regulator board and an ATmega328p breakout. I already have notes to share from soldering one of each to start testing them. The notes in this post are just from assembling them. I will have a separate post that goes into detail about my tests with them.IMG_20140918_193548This is how the boards were designed. They are meant to split apart easily with the tab between them. I got a little excited and went for it without scoring it first, so I destroyed one ATmega328 breakout since the weakest points in that area are the pin pads 2-4. No worries though, I got a few extras in this batch of PCBs, probably because they don’t take up the complete 5x5cm area I have to work with. I tried splitting another board by scoring both sides with a knife and they split cleanly without damage to either design.IMG_20140918_193021This is the AMS1117 board that has two fixed voltage AMS1117 voltage regulators. One produces 5v, the other produces 3.3v. It is a tight squeeze because the capacitor footprint is smaller than the actual capacitors, but it doesn’t seem like it’s an issue. On the back side is a note, written in text that’s a bit too small, that the dropout is 1.3v so you have to supply it with at least 4.6v for 3.3v or at least 6.3v for 5v. I forgot to include the drop of the diode which should be 0.7v, but most applications would probably use a 9v battery as the input to this board. It will be part of the testing, though 1.3v is the maximum dropout so results may vary between the regulators. We’ll see how the tests go.

It was fun placing the SMDs and trying to align them properly. It bugs me when my components end up in some awkward position so I feel the pressure with these small SMDs. I got to solder SMDs back in school where we used a flux pen, solder paste, and a toaster oven. I have none of those things so it’s hand soldering for me.
IMG_20140918_192836This is the ATmega328p breakout board. (The crooked oscillator is bugging me.) I really bumped my head with that terminal block for the power input. The terminal block I used on the board is 3.5mm while I’m sitting here with 5mm (0.2″) terminal blocks, which are the ones found on my Attiny85 board. It’s not a big deal as I can always go and buy them, or I can just solder wires like I did with this one.

The boards have proven to be functional, together no less. Again, full test results will be coming up shortly. Stay tuned! Thanks for reading!

Back to PCBs

With the first fountain show complete, I’m taking some time to consider my next plans for it. I have a few ideas but I don’t have the motivation yet to go through with any of them. I feel like switching gears back to my PCB designs because I had projects going on that had stopped because of the fountain project.
2This is the next board that I’m working on sending out to get manufactured. The main design is the ASM1117 voltage regulator board because I’d like to try working with SMT parts again. I already bought the ASM1117 regulators so I kind of have to get this board made eventually. I’m just a little worried that they won’t work like the shift register boards. I’m still trying to figure that out…

The other design is an Atmega328p breakout. Pretty straight forward.

I hope to send this board out by the end of the week to get made.

AMS1117 + Atmega328p PCB update

combinedI’ve combined the two designs I was working on. The top is the Atmega328p breakout and the bottom is the ASM1117 voltage regulator that outputs 5v and 3.3v. I ordered some parts for this board as there is a sale on at Dipmicro. I’m excited to try SMT soldering with my iron. I need to do some last minute checks on the board to make sure the connections are correct. I’m also waiting for my first boards to come in so I can make adjustments based on those if necessary.

This board includes some things I don’t think I did right in my first PCB. The board has rounded corners, which is not really fixing a problem but it is something new I’m trying. I also went with a small tab between the two boards with some small drilled holes to help make the break a little easier. I’m not sure how the first boards are going to turn out but I’m fairly certain the slot I made in it is not going to be what I was hoping for. Anyways, the last thing is that I didn’t make the top and bottom layers that cover the board part of the ground plane. I’m not sure if that’s really a mistake or not but I know it does help manufacture the board faster (instead of scrapping off everything but the traces) and takes away some traces, as well as some good electrical side effects like helping with interference and noise.

I will be receiving the parts for the boards in this post so expect a mailbag post soon!

Eagle PCB Experiments: Regulator and ATmega328p

As I wait for my first PCBs to come in, I’ve been trying to keep busy in Eagle. As I said before, the first PCBs that come in will teach me a lot, mostly about sizing and spacing. I hope I’m not being mislead too much with the design blown up on my screen.

Anyways, I’ve been working on two designs that will fit on one 5x5cm board. These designs are meant to work together but will be separate, much like my first PCBs.

1The first design is a voltage regulator that will produce fixed 5v and 3.3v outputs. This design uses SMT parts to keep it small, instead of using LM7805 through-hole voltage regulators. I did do it a couple of times in college but we used actual solder paste (no stencil) and a toaster oven. I will have to use my soldering iron this time which may or may not turn out to be a complete disaster. We’ll see.

Quick note, it’s actually AMS1117. I keep mixing it those letters. It’s since been fixed on the board.1Anyways, the regulator is to be used with this ATmega328p breakout board. Using the same terminal block components for 5v out on the ASM1117 board and the Vin for the ATmega328p board, you could solder them together with a male/male header if you chose to use the regulator for the ATmega328p board. I kind of want to add 5v out pins on the ATmega328p breakout board but I want to keep it small. The space beside Vin is so the other half of the regular board has somewhere to go and possibly some text so I can’t really put it there. Again, we’ll see. These designs are still in the making and won’t be sent off until I can see how the first ones turned out.