Author: akim2

Lots and lots of CADs and laser cutting.

All the small misalignments between parts have been fixed using wooden pieces joined together with joints and hot glue. For example, initially, we decided to stick all parts onto the machine permanently, but we discovered that it would be better to have them be detachable. So, I made a detachable wooden case for each of them to hold them in place. There are more of these very small changes that were mostly done using laser-cut wooden parts.

This is the semi-final machine body we have for now. It is only half-functional, because the cylinder connected to the servo does not move the card far enough, making it impossible for the two cylinders at the exit to grab it firmly and dispense it. We are going to add two gears (1:1.4) to the servo and the cylinder to increase rotation.

We were actually supposed to be done with this part already, so we are behind schedule right now. Hopefully, the gears get printed quickly, because integrating the gears into the machine should not take long.

I did confirm that everything else in the machine works perfectly fine, so once the servo issue gets cleared, it should be ready to be tested and verified.

We have a lot to do by next week. Hopefully, the RPi and Arduino won’t cause any trouble as we connect them.

 

Verification:

I will need to test the dispensing accuracy and machine rotation accuracy along with their latencies. Both tests have been done roughly, but the full quantitative tests still needs to be done. The size of the machine already meets the requirement of 20.3 cm x 20.3 cm.

Those complete the hardware and machine body side of the requirements that we have set.

We’re mostly working towards finalizing the sub-components of the machine. We believe that integrating the components could cause various unforeseen challenges that could jeopardize the success of the project.

We assembled the parts in autodesk fusion 360 to get a general sense of how our assembled design will look like in real life. With that, we were actually able to catch a slight flaw in the design and were able to fix it. We can now use this as a guideline when actually assembling the parts.

One potential problem that we may face is that the gears we printed and the motors may not combine very well. The current plan is to simply stick the gears and servo’s plastic parts together with adhesive, but if that does not stick too well, we will need to find another way to make those work together.

 

Our design plan is concrete for now, and we are sticking with what we have. If we encounter unforeseen problems as we actually assemble parts and integrate systems, then we will definitely need to adjust accordingly, but for now, no change.

 

We’re currently following the updated schedule from last week.

 

Worked on finishing up the cad for the components. I finished up the platform for the card shuffler to sit on and exported the dxf file to laser cut. However, techspark was too crowded this Friday, so I am planning on visiting again tomorrow (Sunday) to cut it and assembled them. The positive side about this delay though, was that I was able to discover that the initial design of the platform had the angle too high and was able to fix it. If we went on with that design, it could have resulted in the cards from the shuffler falling out before they could get shuffled.

With that discovery, to make sure that our design looks good, I decided to assemble the parts in fusion 360 to get the full picture. Since I grabbed parts from the autodesk gallery, some parts are not exactly what they are (like the caster wheels, and the shuffler, which I just replaced with a simple box), but they do a good job of showing us the general sense of where we are going. Now with this as the guideline, I will probably have an easier time assembling the parts together.

 

When I assemble the parts tomorrow, if it looks like how it is here, then we are good. If not, then we are behind schedule, so I will need to speed things up.

 

We ordered the sd card for the RPI before break, but it got canceled by Amazon, so we reordered it recently. This has significantly delayed everything related to the main system. Right now we are coding it separately, since we already know it will be written in python.

We planned on using a 7mm mdf for the machine body, but it turns out that 3mm provides enough durability. So, we now have a significantly less heavy machine body, which will decrease stress felt by the servo.

Since we’ve been working on the systems that do not require the delayed parts (SD card), there aren’t any changes required for the schedule.

Machine body printed out.

This week, I cut out the main machine body of ACE, made of mdf. After consulting with a person working in Techspark, I realized that the thickness of does not need to be overly thick. So, I decided to use a 3mm mdf, which significantly reduced the overall weight of the machine. So, I think we can continue using the motor shield we have for now.

I have confirmed that the machine does spin properly, within the latency bound we have set as the design requirement. Right now, I have temporarily put the pieces together in tape, but they will soon be glued together. Once the dispenser gets printed, we can try placing it on the designated space and see if everything works out.

 

Roughly on schedule, with some parts ahead and some parts behind. It was unexpected that our order for the SD card got canceled.

 

• What are the most significant risks that could jeopardize the success of the project? How are these risks being managed? What contingency plans are ready?

No special risk at this moment. However, since our project requires a combination of many components. All parts must be prepared on time to have enough slack time. 

• Were any changes made to the existing design of the system (requirements, block diagram, system spec, etc)? Why was this change necessary, what costs does the change incur, and how will these costs be mitigated going forward?

None

• Provide an updated schedule if changes have occurred.
  

Slightly behind in combining parts to the machine body. It must be done by next week.

• This is also the place to put some photos of your progress or to brag about a component you got working.

DXF file ready to be cut in techspark fablab.

This week, I worked on learning how to make dxf files for laser cutter and making it. It honestly took me a lot longer time to do this, as I had to get the dimensions right.

It also took some time because I wanted to make it in a way that lets me change the hinge size according to the thickness of the mdf I am going to use. This was to add flexibility in our machine body’s design in case we need the material to be less thick to reduce weight or thicker to made it stronger.

Although I did very selectively place the holes considering the size of inner components and their placement, how it actually looks when assembled in real life may be different. So the top part may need to change slightly, but the rest should be fine with what we have right now.

I am behind schedule right now, as I should have already cut this board out this week. So, I will need to do that right away on Monday and assemble them. Good news is that all parts (except for RPI sd card) has arrived, which means I should be able to construct the full machine body now.

I do see it taking some trials and errors, but I hope it won’t take too long. That is why we took some time to plan ahead after all: to reduce number of trial and error.

Now, we have a complete picture of how the machine will look like. We closely examined the required parts and their specifications more closely to make sure they all meet the design requirements we have set for this project. Admittedly, we did run into some problems due to parts we have bought/borrowed that actually did not entirely meet our requirement. However, we have accommodated those and are ready to build the machine starting this week. That is, unless the extra parts we bought arrive late. However, since there was one week gap for the parts to arrive, it would be unlikely.

As specified in the design report, the final size of the machine body will be a 20 x 20 x 6 cm  wooden box, made by combining mdf plates. The size was chosen after creating virtual images of the assembly as shown above, getting a general sense of the amount of space that would be required for all the parts to fit inside. Although we do not have the dxf file for the wooden plates yet, I am planning on quickly creating those this Monday and hopefully cut them by Tuesday.

Then I will assemble those in to a box and add the caster wheels so that I can adjust the placement of the servo for central rotation. Then, I will add weight in side the box to simulate other parts other than the uno to see if we need to buy a different motor shield to support external power supply or the servo. The one we have currently does not, so it will be drawing power from the Arduino, which is generally not a good idea. However, considering that the load is not too heavy, we thought that the servo may end up not drawing too much current.

In short, it was mostly final polishing of the design plan before moving onto the actual assembly.

We are on track in terms of schedule, and if the servo and the 3D printed dispenser case does not cause any trouble, we will very ahead of schedule by the end of this week (though that would be highly unlikely).

One thing that we failed to foresee is the cost of 3D printing. Whenever there were some parts that seemed ambiguous to purchase or required complex and custom design, we decided we would use 3D printing to make that. However, we only realized later that 3D printing will cost a lot, given the size of the parts we’re trying to print. As such, we would have to aim for reducing the number of trials and errors of printing. Our plan is to make the design as precise as possible to work as we intend it to be. To that end, we’re carefully considering the dimensions of the parts and trying to have a concrete overall design for our parts to assemble later.

No significant changes were made to the existing design of the system. After realizing that adding too much load to the servo may draw too much current, possibly causing problems with the arduino that will be powering it through the 5V line. So, we may decide to use a weaker servo for the dispenser to draw as less power as we can from the arduino, and we are planning to add 4 caster wheels to support the weight of the machine body for spinning.

This will mean additional budget use for buying the wheels, but it is minimal, and we have not used much of the budget so far, so it will be fine.

Motor control code ended early, so Andrew will be helping with building the dispenser and case. Hopefully, the dispenser will be done earlier than we expected.

We have confirmed that the servo works fine. Additional tests will need to be done to see if the 5V power supply from the Arduino will be enough when we add load to it. Such concern was the exact reason why we decided to add wheels to the design for additional support while reducing friction.