Hey, what is going on my beautiful, nice, and smart readers. I am quite sorry that I have not been posting as often as I would like to lately. My last post was in January, and ever since then I have not done much with the website. I will have a general update in regards to what has been going on in my life, as well as with the project coming soon. I have not been writing or making videos mostly because school, work and other activities have been keeping me busy. All I can say is that there is a lot of very interesting stuff coming soon.
What were we talking about again? oh yeah the Tiny slammer. The Tiny Slammer is one of the projects that I really wanted to write about but never could due to lack of time. As a matter of fact, I was not able to do the final testing and assembly until a couple of days ago, which is crazy because I did the design and manufacturing months ago.
Overview
The Tiny Slammer is a very simple breakout board designed for easy prototyping with the ATTiny 25/45/85 DIP-8 micro-controllers. It gives you easy access to all the pins on the micro-controller, as well as other features. These features include:
- On board LED (Connected to PB0)
- Separate connector for supplying power (Batteries or Power Supply)
- Separate pins for easy programming
- DIP-8 socket for easy removal of micro-controller
There were two main reasons as to why I decided to design this PCB. First, I always liked how simple yet powerful the ATTiny micro-controllers were, but did not like how hard (more like unconfortable) it is to prototype with them on bread-boards, or to program them. I wanted a solid package in which you could do all your prototyping in, and then just remove the chip and put it on a PCB. Second, I always wanted to design a PCB and have it manufactured. It had to be a small PCB which would not cost a lot of money to have manufactured, but at the same it had to be somewhat useful. Luckly, the guys at OSH Park helped me out with the project by giving me some coupons to have the PCBs manufactured by them. In the end it, I ended up “paying” about $9 for 6 PCBs, with free shipping, which is not bad at all. Though the first batch was not lucky enough and got lost in the mail (RIP in peace first batch). After hearing about the fate of the first batch, OSH Park responded quickly and had the PCBs remade and shipped in less than 4 days. Big props to OSH Park for being such a great company. 10/10.
The PCB was designed on KiCad, the open source PCB design software. It took me about 6 hours on a Sunday to design this PCB and to be honest, it was not even that hard to do. It could have taken much less time if I was proficient with Kicad but oh well, it was a good design to practice with. The board is completely open source and eventually I’ll be adding the files to a Github repository, where you will be able to download it, and do whatever you want with it. I would recommend having the PCBs made with OSH Park and sourcing the parts from Digikey.
As stated before, the Tiny Slammer allows you to have easy access to all the pins on the micro-controller. On the left side of the board you will find the sockets for PB5, PB3, PB4 and GND. On the right side you will find VCC, PB2, PB1, PB0. These socketed pins allow you to have easy access to the I/O and power of the micro-controller. You can use male jumper wires to connect devices and other circuitry to them. At the top right you will find easy access to the power pins of the micro-controller. You can either solder sockets, wires or any other type of connector in order to supply power to the micro-controller. During the test of the PCB I used these sockets to provide power to the Tiny Slammer with my variable power supply. The Tiny slammer also has some programming pins located at the top right of the PCB. These pins make the Tiny Slammer pin compatible with those programmer sold on Ebay which you can pick up for a couple of dollars in order to flash code into the ATTiny. With one of those programmmers it is as easy as just connecting it there and you should be good to go. At the bottom of the PCB we have an LED and a 220Ω resistor for current limiting. These two are connected to PB0 and ground. The two are also 1206 parts which are the smallest parts of the build and the harder ones to solder in place. This LED is a testing tool, which allows you to make sure that your micro-controller is working properly or to be implemented in your projects. Lastly, in the center of the PCB we have a DIP-8 socket for easy removal of the micro-controller.
Now that we have discussed the reasons as to why I made this PCB, along with the parts that comprise it, why don’t we just assemble it? sounds good? okay.
Assembly
In order to fully populate the Tiny Slammer, here it’s what you’re going to need:
- 1 x Tiny Slammer PCB
- 1 x ATTiny 25/45/85 (DIP 8)
- 2 x 4 Pin Sockets
- 1 x DIP 8 Socket
- 2 x 3 Male Header Pin
- 1 x 1206 LED
- 1 x 1206 220Ω Resistor
Note: The links to parts are examples of ones that you could buy. You could buy them from different sources or use different parts, such as different color LEDs, switch female sockets for male ones, etc.
Note 2: For the battery, you can either solder the wires directly, add a 2 pin female socket or 2 pin male. In my case I went for the 2 pin female socket and male jumper wires connected to them to power the micro-controller.
Step 1: Soldering the LED and Resistor
For this step, we will need:
- 1 x 1206 LED
- 1 x 1206 220Ω Resistor
This step is one of the trickiest ones, that’s the reason why we will do it first. If you do not do this step first, it will become very hard to do once there are other parts around them. SMD parts are very small, and can be hard to solder as well. Be sure to not sneeze while soldering the SMD parts or you will send them flying away.
So, how do we solder these SMD components you ask? well, first you need to place a blob of solder in one of the pads. Take your SMD part and then hold it next to the blob of solder on the pad with tweezers. Heat up the blob of solder with your soldering iron until the solder flows towards the metallic end of the SMD part. Wait for the solder to cool down and you will notice that the part is held in place by the solder now.
For the second solder joint, you can do it like any other solder joint, use your soldering iron to heat up the pad and the metallic end of the part and then melt your solder. This will join metallic end of the part and the pad, creating a nice conductive path.
For soldering the LED it is slightly different, because LED’s have to be soldered in a specific way due to their polarity. Here it’s a diagram on how to tell what is the polarity of an SMD LED:
In my case, the LEDs that I purchased had the 3rd type of marking. The bottom of the T will point towards the anode, similar to the way the regular symbol of a diode does. Solder it in the same way as the resistor and you should be good to go.
The goal here is not to get perfect solder joints, but get solder joints that “work”. In my case, one of the sides of the LED had a lot more solder than the other one, but in the end it worked well.
Step 2: Soldering the DIP 8 Socket
For this step, we will need:
- 1 x DIP 8 Socket
In this step we will just be soldering the socket for our ATTiny. This is very simple to do, the first thing that we need to do is insert the socket on the right way. The socket has a notch (which you can see in the picture, facing towards the top). That notch needs to be aligned with the one on the silk-screen of the PCB.
Insert the socket, and then flip the PCB on it’s back. Then, solder two of the corners (laying opposite from each other) of the socket. Then, solder all the remaining pins. Make sure that your pins are looking smooth and shiny!
Step 3: Soldering the 4 Pin Sockets
For this step, we will need:
- 2 x 4 Pin Sockets
This step is similar to the one soldering the DIP 8 socket, but a little trickier. You need to first insert the 4 pins sockets in their respective places, and then flip the PCB upside down. Now here it’s the kicker, they will try to move on you, so you need to have a steady hand so the sockets stay parallel to the surface that you are working on and allows you to solder them in place. Always start soldering them by tacking at least one of the corners, it will make it much easier to solder all the other pins. When you solder the first corner, make sure that the sockets are being soldered straight, if they are not, it will not be too detrimental, but they will end up looking odd.
And ta-da! the 4 pin sockets are soldered in place. As you can see my right one is slightly skewed, but it does not really matter since we will be connecting male jumper wires to it anyways.
Step 4: Soldering 2 Pin Socket
For this step you will need:
- Anything you would like to use as your “battery connector” (in my case 2 pin female socket)
In my case, this step was basically the same as the previous one where I soldered the sockets in place. The funny thing is that I did not have a 2 pin female socket, but I had 2 x 1 pin female sockets which remained from cutting down bigger sockets to use the previous step. Don’t blame me! I only had 6 pin female sockets!
This part was slightly more tricky than soldering the 4 pin ones, because these will move around far more, which required a more steady hand to solder in place.
Step 5: Inserting the ATTiny
For this step we will need:
- 1 x ATTiny 25/45/85 (DIP 8)
This step has to be the simplest one out of all the steps. What we need to do is just insert our micro-controller into the DIP 8 socket. This has to be done in a very specific way though. Our micro-controller should have a dot on it’s top surface, that dot will indicate it’s first pin. That dot should align with PB5, which is technically the first pin of the ATTiny.
You will also need to make sure that your micro-controller slides in smoothly into the socket. Sometimes during shipping, the pins of the micro-controller or any other DIP chip might get bent and could make it harder to insert the chip into the socket. Before inserting the micro-controller, make sure all the pins are straight. If they are not aligned with the holes of socket, you can bend them with your fingers or using small needle nose pliers.
Step 6: Soldering Programming Pins
What you will need for this step:
- 2 x 3 Male Header Pin
This step is basically the same as the previous ones where you had to attach the sockets, but this time it is with the pins. To make it easier for yourself, you can solder one row of pins at the time. Remember to tack the corners first so your pins will not move around while you solder the other ones.
Note: I purposely did not do this step for my boards because I currently do not have a programmer for the ATTiny’s. Instead I have been using a board that I put together a while back in order to use an Arduino UNO to program ATTinys. I am able to just program them and place them on the socket of the Tiny Slammer. This is not optimal of course because every time you remove the micro-controller from the socket, you are excerting stress on the legs of the package, which could break them at some point. TL:DR Don’t be as stupid as I am and get the programmer. Should be one of these. If you would like to make an Arduino based programmer, go here.
Testing the Tiny Slammer!
Now that our board is finally complete, we will need to program it and test it. To program it, we will need our programmer and to follow a guide on how to program our ATTiny. You can go here if you need one of those. To test our ATTiny, we will just be using a “Blink” sketch that will blink the led located in our Tiny Slammer. You can go here to download the test sketch. The pin to which the LED is connected should be PB0 or just 0 on the Arduino IDE. Feel free to change the sketch around to make the test more fun.
Now we can connect the a power source to the power pins of our Tiny Slammer. If our board is working, then it should flash every half second.
If you just finalized the assembly of the Tiny Slammer, then congratulations! You now have one of the smallest prototyping breakout boards out there. This board was very easy, quick and fun to build. I do hope that if you decide to build one, it will help you as much as it did to me in order to simplify the prototyping stages of some of my projects. If you have any questions in regards to this breakout board, it’s assembly or programming, feel free to leave them down in the comment section below.
