On day 5 I got all of the limit switches mounted to the machine. I spent some time trying to figure out where and how I wanted to mount the switches. I also needed to find an easy way to actuate them when the machine reaches a limit. I scrounged around in my junk parts bin and came up with some pretty neat methods on how to actuate the switches at each limit. The main requirements of my chosen scheme is to make it look neat and keep it functional. Go here to read about the ongoing build and take a look at some pictures along the way.
I typically send my circuit boards to ITead Studio to have them produced since it is cheaper than ordering them from US companies. International orders can take a long time to ship..usually around 3 weeks. This can become painful if I find a mistake in my design and have to re-order boards. This is why I occasionally bite the bullet and have them made locally. One of the techniques I use to minimize the cost is to place multiple circuit designs onto a single PCB. The problem with doing it this way is there are no snap off tabs between the circuits like you would receive from a panel. There are numerous methods that a hobbyist can use to separate the circuits such as a Dremel or saw. I want a clean cut so using a Dremel tool is out of the question. Also, the material the boards are made of is toxic thus, it is not recommended you cut them out on a table, band saw, etc. A PCB shear will give you a clean straight edge and makes short work of cutting out the individual circuits. I have seen some individuals using a heavy duty paper shear but, I wanted something that was more accurate with a longer lasting blade. The shear is available from T-Tech. The cost is a tad on the high side but, it is better to spend now and save later IMHO.
Here is a picture of the PCB Shear:
Day 4 of the build is now in the bag. Updates on the V90 status slowed down a bit as I had to wait for the limit switches to arrive. I got the limit switch assemblies completed minus mounting them to the machine. Go here to read about the ongoing build and take a look at some pictures along the way.
I’m currently working on documenting this project but, here is a link to my entry for the DesignSpark Challenge. The competition has already been decided and my entry garnered an honorable mention award! This was the first competition that I entered and to win an honorable mention out of over 1000 entrants means a lot to me. I also won a Community Choice Award during the competition for the most popular project. I have to say this was a difficult competition as there was a lot of requirements. For instance, I had to learn how to use DesignSpark PCB as it was required to produce an extension board for the ChipKit Max32. I had to learn the ins and outs of the Max32 as it is/was not entirely compatible with all of the Arduino libraries. This meant some modifications to libaries in order to make them compatible with the Max32. Lastly, there was a long wait for the PCBs to be shipped from China which meant any mistakes in the board files meant lost development time (I made a few mistakes). Time management was definitely crucial in this competition and I ran all the way until the last few minutes for project completion trying to get everything together. A few mistakes kept me from adding all of the software features that I had intended but, I have pretty much completed them since the competition. Check out my entry here and be on the look out for full documentation on my blog to include some extension projects (There’s a lot of goodies in this design that can be carried over into other projects).
I have used many schematic/PCB capture applications and I find that Cadsoft Eagle seems to be the standard for hobbyists. As such, there are some peculiar features that takes some getting use to. For instance, the user interface does not function like many point-n-click applications. You can Google eagle tutorials and find plenty.
Below are some of my favorites:
Here is another parts post for a 12V @2A switching power supply. This unit is small and has an aluminum case with cutouts for mounting. I used this power supply in my Reflow Controller project. You can find it on ebay here (link will expire) or search for a DC 12V 2A Switching Power Supply Regulated. You will more than likely get multiple results.
Most of my projects require some type of power source. Now, I could go the DIY route and build my own power supply or I can do a search on ebay and find what I am looking for already finished and ready to go. Here we have a Minghuada MHD-10VA switching power supply that accepts 110-220VAC and outputs 5V @2A. This unit is small and has an aluminum case with cutouts for mounting. You can find it on ebay here (link will expire) or search for a DC 5V 2A Switching Power Supply Regulated. You will more than likely get multiple results.
Day 3 of the build went somewhat quicker than day 2. I got the machine fully assembled and operational (minus adjustments). Go here to read about the ongoing build and take a look at some pictures along the way.
Day 2 of the build is a wrap. I got more accomplished today than I thought I would be able to do. I managed to unwrap and inspect the remainder of the parts in addition to assembling the gantry and the base. Go here to read about the ongoing build and take a look at some pictures along the way.
A while ago I decided to start designing my circuits using Surface Mount Devices (SMD). There are many advantages to using SMD components over through-hole components. Some of the major advantages are size and cost. The smaller size means I can make the circuit boards smaller. In addition, smaller components and smaller circuit boards means lower costs. One of the disadvantages to SMD components is they are more difficult to solder than through-hole components. The solution is to use what is called a reflow oven. The following project details how I designed and built a reflow controller based on a MAX6675 Thermocouple interface and use it to control a common toaster oven in order to reflow surface mount circuits. Check out the project here.