Replikeo Prusa i3 Rework Build - Part 2: Assembly

Part 2 will describe the process of building my Replikeo Prusa i3 Rework. Having already taken inventory in part 1, I will continue following the wiki instructions with Y-axis assembly. Below are the pictures from the build.

Y axis assembly

Y axis assembly with carriage

X and Y axis assemblies

X, Y, and Z axis assemblies

Z Steppers added

Attach uprights to base and add X,Y steppers

I don't remember having any serious problems with this portion of the build. I was able to put what you see above together in a few hours. Some screws were too long as I had seen documented elsewhere. I just put some extra washers underneath them. On the z-axis threaded rods, the nuts did not fit snuggly into their housings, so I added a drop of hot glue to each. Other than that, I pretty much followed the instructions. Next was the extruder assembly.

The extruder assembly required a little teasing. It is worth noting that this is the only printed part that is included in the kit. As such, some trimming of support material was required. I was not overly impressed by the print quality. I plan to print a replacement at some point and expect mine to come out much better. The biggest problem was that the hole for the j-head was not round. Luckily the j-head is almost exactly the same diameter as the drum sander attachment on a dremel tool. A bit of sanding and it was good to go. Below are some pictures.

Assembly before stepper

J-head hole enlarged

Hot glue added to keep bearing in place

Fully assembled extruder before stepper

At this point the only things left to do were add the heated bed and wire everything up. Wiring will be in part 3, but I will put the heated bed pictures here. I debated for a while how to best attach the thermistor. Eventually I ended up using silicone sealant and some kapton tape I had. The wide kapton was not included in the kit, but many smaller pieces of the stuff included in the kit could be used if that is all you have. In the end, the silicone did nothing. I would just leave that off.

Thermistor included in the kit. Wires are presoldered and heatshrinked

Thermistor taped to heatbed

Printer ready to be wired

Its worth noting that I used springs to support the heated bed instead of washers like in the wiki instructions. I think it's fairly obvious how to do this; the springs are included in the kit.

At this point the only wiki page left is Electronics and Wiring. Part 3 will address wiring and initial software setup.

-Matthew

KY3361ABR-242 Mini Volt Meter

This is a mini review for a volt meter I picked up off eBay a while ago for about $1.50. I don't know that it has a name, so I have decided to call it the KY3362ABR-242 Mini voltmeter. I suspect KY3362ABR-242 actually refers to the display, but regardless it is written on the bottom of the volt meter. That is what I am calling it. As you can see in the pictures, V1303 and DV036A are also printed on the back, but I am ignoring those.

Not a whole lot of information was given with this purchase, but what the seller offered I saved for posterity below.

Specifications:

• Measuring range: DC 0V--30V
• Input range: DC 2.5V-30V (Max Input: DC 30V. The device can be damaged if input is over 30V)
• Display Color: RED
• Display: Three 0.36 "digital tube
• Measurement accuracy: 0.1%
• Refresh rate: about 300mS / times
• Input impedance: About 100K
• Dimensions:33mm*15mm*10mm
• pitch of holes:28mm
• aperture size :2.8mm
• Operation Temp: -10℃-+65℃

Wiring:

• red:power supply +
• black:power supply -, measure -
• white:measure +

I soldered on some nice male headers with some heat shrink and got to testing. Here are the photos.

Measuring the 3.3 V supply from my MB-102 power supply

Measuring the 5 V supply from my MB-102 power supply

Measuring the 5 V supply from my Arduino Mega powered over USB.

As you can see, the mini voltmeter consistently read close to the same thing that my craftsman meter read. Granted that is not the best benchmark, but it is what I have. It is also interesting to note that the KY3362ABR-242 can even measure the power supply from which it is being powered.

All in all, this is a very nice little purchase. I would definitely pick one up if you have a need. It is not going to replace your multimeter, but it is a very nice real time display for breadboard power supplies or similar. You can also do cool stuff like hack it into an I2C display.

Recent Purchases: Mini-reviews

Well I thought I should mention some of my recent purchases that made the below project possible. I'll try to make this brief. If you haven't seen that project, go back two posts.

ATtiny85: I got this off of eBay for a few dollars. In the future, I will probably buy them somewhere else, but I just wanted one, so that was the cheapest thing to do. I am pleased with it.

Solderless Breadboard: 830 point solderless breadboard. MB-102. Also from Ebay. $4 shipped. I like it. It is twice as big as my other ones and the roominess is nice.

MB-102 Power Supply Module: Thats the thing on the left. It works really well. I am quite pleased. It takes a center positive power supply or a male usb A. It is switched and can provide 3.3V or 5V. It plugs right into the power rails of the board. $2.15 shipped from Ebay.

Jumper Wires: Yes I sold out and bought some ready made jumpers. I'm glad I did. They are stranded and thus much easier to work with. I was getting all my plain white wires confused. The colors make it easier. Note that I did not get an even distribution of colors. I got 65 total and maybe 3 were black. $2.39 from Ebay. I've only found one so far that doesn't work.

10K pot: I got these from Ebay a long time ago. I don't remember how much they were, but it was a few dollars for 10. They work ok. They were 10 +1-2 K. But for my purposes they were ok. A slight annoyance, the pins aren't long enough to go into a breadboard. Had to solder on some...

Male Headers: I got ten 40 pin rows of them for $.99 (Ebay-China)

HXT-900 Servo: These are my favorite servos, hands down. Cheap. Simple. Reliable. They are sold under various names much as sg-900 and towerpro. They are the 9g servo from HexTronik Ltd, the company that manufactures everything for Hobbyking. Get these servos HERE. And if you manage to strip the gears, get the replacement HERE. Its also worth noting that they sell a 5g version HERE. I did a write-up about HobbyKing in one of my first posts. I also got my first Arduino there.

Other: I also got 10 paper prototype boards from Ebay for $1.38. They had a bit of a chemical odor and were not the best, but they will do for messing around. Hobbyking also sells some higher quality stuff that I have bought. The green stuff. Its HERE. That stuff is pretty nice.

I have got some female headers as well for various projects that I have in my mind. They seem pretty decent. I got 10pcs 1x40 breakaway female headers for $3 from Ebay.

USBtinyISP: I put this last because I really have already mentioned this quite a bit, but I love this thing. It is extremely easy to use. You might look into the tinyProgrammer instead if you just want to do ATtinys, but this was $15 on Ebay from a US seller. It is high quality and I love it. Check out some of my past posts tagged USBtinyISP.

That's all I have for now. Go forth and spend you're hard-earned money.
-Matthew

Review: HobbyKing Arduino Sensor Shield V4.

Well I'm back. Here comes the last of the promised reviews before we get to the fun stuff.

Today I am reviewing the HobbyKing V4 sensor shield as found HERE. Now, when I ordered this shield this was the only one available. However, I have noticed that they have other versions now too (the V5 and others that are just different colors.. Don't ask me what's up with that. I don't know).

If you prefer these shields they can be found HERE and HERE. I will mention some apparent differences in these later, but be warned, I don't have those boards. 

When I got this shield I didn't really know what I was buying. I was completely new to Arduino, but I saw sensor expansion board and thought, "Yeah, I want to connect sensors." Well shows what I knew. The obvious fact is, you don't need this board to connect sensors. It just makes it more convenient to do so. It gives you nice male pins to plug all your sensors into.

The two things that really attracted me about this board was 

A. It was cheap. $5.20 is pretty good.

B. It appeared to be made to connect standard hobby servos to the Arduino.

Well this is partially true. It is cheap. It is a great price. 5 stars there. But B. Well it does make it more convenient to plug servos into the Arduino, but if you are going to be running more than one servo, you will need to wire in external power. I will go over this in a later blog.

Basically the Arduino can only provide 40mA per io pin. Some people claim more, but don't tempt fate right? Servos can draw considerably more than that depending on the circumstances, size, etc. But let me say this,

This board does NOT allow for an external power source to be hooked up to power the servos.

There. You have been warned. The v5 supposedly does have some such deal that allows you to wire in power to the V pins (look at the picture) preregulator via the added screw terminal. I have no idea if this works well or not. I personally would do it myself and not risk it.

That is about it on this shield. It does do what it says on the box. I will note that it fits on the Mega. It leaves the back half of it open so that you can still access the unused pins. The only issue is that the I2C port is not on the same pins as on the shield(the shield is made for an Uno), so you will have to wire it manually (to pins 20 and 21, but that will come later). For an Uno it should work fine. In case you don't know what I'm talking about, that isn't a reason to get an Uno instead of a Mega. Still get the Mega. Its cooler.

• Price: I already covered. ~$5.00. Can't really beat that.
• Documentation: Well there isn't really any, but its kinda self explanatory when you get it. It just wires the io pins, 5V, and gnd to male pins for easy sensor connection.
• Quality: I have been very happy with it. It has lived on top of my Arduino since I got it. Very sturdy. All the solder connections seem good. I am happy.
• Durability: It has withstood me tugging at wires and such for several months. I would say it is on par with any other shield out there. I can't see you doing much better.

Overall, it is a nice shield. I would recommend it or the v5 to anyone. If you are trying to decide between the two, its really up to you. I'd get the v4 and save $5, but a valid argument can be made for both sides. I'm just cheap.

"I'm broke. Is this absolutely necessary?"

No. Of course it isn't. Get it anyway. You'll thank me later. I is an extremely useful tool and will make your life easier. Allow me to explain. I didn't buy real hookup wire. I use some extra wire (22awg I think) from when my dad and I replaced the garage door opener at the house. Well at some point I got over zealous with the wire strippers and nicked the wire. I now have a little piece down inside one of the gnd pins on... the shield! Not my Arduino. Yes this is a good thing. I'd rather break a $5 shield plugging and unplugging stuff than a $18 Arduino. It is also completely stackable (though not really functional to do so). Plus, it will fit nicely in a HobbyKing order with the Mega and one other shield. I know. I did this. Just get it. You'll thank me later.

So anyway. This should be the last of the long HobbyKing reviews for a while. Next I'll post some pictures and begin talking a bit more about what I did with these parts. I'll also list some other parts you might want to get (jumpers, resistors, etc.). There are cheaper places than Radio Shack. Trust me. So stick around. 

Until Later,

Matthew

Review: HobbyKing Arduino LCD Keypad Shield

Welcome back. Today I will be reviewing the HobbyKing Arduino LCD Keypad Shield (this blog won't be all reviews I hope, but this seems fitting).

When I first ordered my Arduino this was one of the two shields that I ordered with it. It is just what it says on the package. It is an Arduino LCD shield with 5 buttons (6 if you count the reset). It fits perfectly onto my Arduino Mega from HK. I would post a picture of this, but my Arduino is busy at the moment. I honestly have not used the shield since maybe a month after I got the board. It does have 5 buttons you can use, but I quickly moved on to greater things.

This board does not use the serial connection like I understand some LCD shields do. This one actually uses a combination of pins. While all of the pins it plugs into are not used, and one could theoretically solder on headers to the blank holes left on the unused pins, I do not recommend this to the beginner. Or really anyone. It just seems like a bit of a waste of time. You have another 30 or so IO pins still open for your use.

Now, I began trying to make this shield work with no programming experience whatsoever. I have been around robotics long enough to have a basic understanding of programming logic, but I lacked any knowledge of syntax, etc. I managed to get it to work with only code examples I stole off the hobbyking website. I did not write this code nor can guarantee its effectiveness, but I have put the code in my Google Drive in case Hobbyking decides to remove it. It can be found HERE. I hope this will help anyone that may need it.

But anyway.. I should cover the major points. First, you can buy it HERE.

• Price: It is regularly $8.99, but if you leave the page open for a while it will give you an offer to buy it for $8.32. So I would do that. This is very competitively priced. You may be able to buy something for that price on Ebay, but I would far prefer to get it from a company with a face and reputation to maintain. Plus, I trust Hobbyking more. Call it a fools trust, but they've never treated me badly before except out of my own stupidity.
• Documentation: Again, there isn't much, but a quick Google search is all it takes to get some. Besides, you're of the tech generation. you wouldn't have read the papers anyway. And this is more fun.
• Quality: I must admit, the quality was not as nice as the Arduino itself. It was a little rough around the edges, but overall I would say good quality. Mine worked perfectly. It came wrapped in nice anti-static packaging. Seemed like grade A stuff (perhaps an A-).
• Durability: Well its an Arduino shield so.. it ain't great. But mine survived while I used it.

Overall, this is a nice little board. If you want one, I'd say go for it. I don't know how it stacks up with the serial version they sell. I don't have one of those, but this thing does what it says. It gives a cheap display and five buttons to play with. 

Now, I am glad I have it, but I honestly haven't used it in a while. I have moved on to do more robotics oriented stuff, and it just gets in the way. If you are tough on cash, I would not rate this as a must have. But if you are looking to build a well rounded Arduino arsenal, for $12 or so with the shipping added, I don't see how you could go wrong, especially when the other one (HERE)  is over double the price.

Check out these cool projects using this shield HERE and HERE

That is my take on things anyway. Hope you found this useful and will tune in again sometime. 

Until later, 

Matthew

Review: HobbyKing Arduino Mega

For the Arduino section I thought I would start with a review of the Arduino I have at the moment. When I got into messing around with Arduino, one of the main concerns was cost. In fact, the main reason I ever thought of getting one was because my favorite store for cheap RC parts began selling Arduinos.

Enter the Arduino Mega 2560 purchased HERE, at HobbyKing.com.

Now, let me first give a word of warning to all those that might follow me. HobbyKing is based in China. As I live in TN, USA, this has some very important implications.

1. Orders take a long time to get here.
    I believe most of this time is spent on the China side. Using the terrible order tracking system of the Chinese postal service that is what I have deduced. Once it gets to the sorting facility in Chicago or where ever it comes stateside, it's usually only a few days. Nevertheless, plan ahead.

2. Quality Control can be lacking.
     If you are ordering cheaper items like $2 servos expect 1 in 15 or so to be bad. It happens. Luckily the price is such that ordering an extra is ok.

3. Descriptions don't always match the product and/or they can be deceiving.
    While this has gotten better over the past few years, descriptions sometimes can be deceiving. This has improved as I believe HobbyKing has hired some Americans to take over the English side of things, but dimensions remain in metric which to a lazy person like me can be tricky. I tend  to guestimate how big something is rather than get a ruler and actually see how big it is.

4. Shipping is a bit pricey on some items.
    Shipping on small orders is payed by the gram in increments of 100 grams. This means that it is in your best interest to use every gram up to the limit on your current pricing tier(they make it easy to find little bags of screws to spend extra money on). Pricing starts at $3 for 100 grams and goes up after that. However, I usually have found that the difference in item price more than makes up for the difference.

5. Things go on backorder for long periods of time.
    This means if it is on backorder, it could stay that way for a few months. But the Mega is in stock right now so GO GO GO!

Now that we have all of that out of the way, the review. Now lets again not forget who is writing this. I am 19 and a Sophomore majored in Mechanical Engineering. I'm not a EE with 40yrs experience building NASA Flight hardware. I am just a practical person giving an honest opinion based on my experiences to far.

So anyway.. I am reviewing the Arduino Mega 2560 Microcontroller Board as purchased from HobbyKing.com at the below link.
http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=25085&aff=272191

• Price:  The price is obviously fantastic. $17.69 vs the $50ish for a "real" Italian Arduino Mega is pretty good. At this price I would highly recommend to the beginner to get the Mega over the Uno. It just has so many more features and allows you to spread stuff out across 54 Digital IO pins to avoid confusion.
• Documentation:  Well HobbyKing has none. But luckily everything at Arduino.cc is open source, both hardware and software. So THIS documentation works just as good. Given my style, I have never really looked at it honestly. If I had a question, I Googled it.
• Quality:  This kind of surprised me but I honestly a very happy with the quality of my board. I don't have a "real" (the HobbyKing version is  a clone) one to compare it too but the board is nicely made. Good solder joints. Nicely deburred. I am happy. And as far as I have seen, it works just like an Italian Arduino. Maybe there is some difference in processing speed. I don't know. But is it worth $30  extra for an Italian version? In my mind, nope.
• Durability:  Well its a PC board so.. It ain't great. But I have been rougher than I meant to be(both physically and electrically) a few times and it survives. And if it breaks you can spend the $30 you saved to buy another one.

Final Thoughts: I love this board. It works well and has been great for me to learn basic robot programming (a peek behind the curtain of things to come). I would recommend it to anyone. As far as I can tell, it meets the description perfectly. It comes with a usb cable and electrostatic packaging. That's it. I haven't need a power supply, but if you want one, most people with "the nack" have an old cordless phone or 2 sitting around. If not, look HERE and then surf ebay to pick one up for a few bucks. 

I plan on writing again soon with reviews of the other two shields I bought.

The LCD Keypad Shield and 

The v4 Sensor Expansion Shield

After those two reviews I plan on going into the story of my arduino projects including a bill of materials and mini reviews of all of the sensors and components that I have purchased and lessons that I have learned regarding such purchases. In the meantime, research Arduino. Download the software and peruse the website. Also look into HobbyKing and their US competitor HobbyPartz for future purchases, investments in your Arduino arsenal. 

Until next time,

Matthew