View Full Version : Goal: a desktop cnc machine Level: Beginner
I was wondering if there were any electronics experts on the forums that can be a mentor?
The goal in the end: I would like to build a desktop sized cnc machine and I thought perhaps others on the forums would like to also. This is just to give an idea of what a low cost cnc machine is: http://www.instructables.com/id/Easy-to-Build-Desk-Top-3-Axis-CNC-Milling-Machine/
The steps I had in mind are:
1. pick an electronics learning kit that we could all buy and go through the lessons.
2. move to a microcontroller, arduino, beagleboard, teensy, pic etc. We could discuss all of these and select the one that the majority agrees on.
3. go through learning kits for the selected micrcontroller
4. get into controlling various motor types. Almost all of the cnc I see use stepper motors, but it would be neat to learn about dc motors as well as they are cheaper usually.
5. come up with a nice design, for a cnc machine on our own. They sell plans, but what is the fun in that?
6. building a machine is only the start, then comes the software side. Again they sell programs and there are even open source ones, but it would be fun to write our own.
Another major goal would be to keep the cost as low as possible.
Here are some prices in dollars to give an idea, again I want to stick on the low side, but will leave it the group and mentor:
electronics learning kit, ~130 in 1 about $40 to 500 in 1 for $250 http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=PL130A
microcontroller $16 to $200, http://www.pjrc.com/teensy/ to http://pandaboard.org/
Stepper Motors: Too many variables for me to judge which we need to use, but they range from around $15 to $100.
Rotary Tool $11 to $80 http://www.harborfreight.com/80-piece-rotary-tool-kit-97626.html dremel http://www.google.com/products/catalog?q=dremel&hl=en&safe=off&rlz=1C2CHFX_enUS458US458&prmd=imvnsr&bav=on.2,or.r_gc.r_pw.r_cp.r_qf.,cf.osb&biw=1920&bih=1075&um=1&ie=UTF-8&tbm=shop&cid=15843362292486617096&sa=X&ei=zDU8T53OBInu2gWEi6XzBg&ved=0CJABEPMCMAM
They say the first cnc is the low cost ugly one and then you use it to build your bigger machine next.
After we get a cnc working, then we could move on to making robots with parts we make from our cnc machine :)
Let me know of any other ideas and hopefully we can have someone on the forums to guide and mentor us.
i have made experiments with simple electronics only, so i can't be an adviser for this project, it seems complex for me.
the electronics learning kit from ramseyelectronics.com you have referenced seems amazing.
i know some valuable resources:
the best free online lessons (descriptive with full illustrations, without math, or very little math) is:
Lessons In Electric Circuits /by Tony R. Kuphaldt
http://openbookproject.net/electricCircuits/
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can be downloaded as html (29 MB) from
http://openbookproject.net/electricCircuits/liechtml.tar.gz
also as pdf files. not all lessons sections are complete. use google to search the lessons.
the best section is the last section :
Volume VI- Experiments
don't forget the Socratic Electronics Project from the same author:
http://www.ibiblio.org/kuphaldt/socratic/index.html
the best author for simplified electronics is "Forrest Mims" such as his book "Getting Started in Electronics" and many others.
Ken,
Have a peek at what LEGO Power Functions (http://powerfunctions.lego.com/en-us/whatis/default.aspx#HowDoesPFWorkContentProvider) has to offer.
John
Thanks John, I had not heard of those but only the mindstorm robot kits. These would be interesting for the robotics intro perhaps?
Just saw your edited post, will look at that video now, thanks!
Something sort of similar but only remotely that I have come across are:
Microsoft Gadgeteer
http://www.extremetech.com/computing/91990-gadgeteer-microsofts-open-source-net-alternative-to-arduino
http://www.youtube.com/watch?v=wQlTLNOCl90
Sun/Oracles:
http://www.sunspotworld.com/index.html
http://www.youtube.com/watch?v=tv5ZaN9tSck
i have made experiments with simple electronics only, so i can't be an adviser for this project, it seems complex for me.
the electronics learning kit from ramseyelectronics.com you have referenced seems amazing.
i know some valuable resources:
the best free online lessons (descriptive with full illustrations, without math, or very little math) is:
Lessons In Electric Circuits /by Tony R. Kuphaldt
http://openbookproject.net/electricCircuits/
7818
can be downloaded as html (29 MB) from
http://openbookproject.net/electricCircuits/liechtml.tar.gz
also as pdf files. not all lessons sections are complete. use google to search the lessons.
the best section is the last section :
Volume VI- Experiments
don't forget the Socratic Electronics Project from the same author:
http://www.ibiblio.org/kuphaldt/socratic/index.html
the best author for simplified electronics is "Forrest Mims" such as his book "Getting Started in Electronics" and many others.
Thanks Zak for the links, I will check them out. I had some Forrest Mims books awhile ago. I read them, but it did not stick with me.
I heard this great Chinese Proverb quoted by an Indian Professor teaching electronics on youtube. I really agree with it.
I read, I forget
I see, I remember
I do, I learn
So I need videos and to do and have a place to ask questions and get answers. I guess will have to give it a week or so and see how many people are interested first of all.
Thanks again for the links.
John, just watched the video of the lego machine. That was neat how you think he, oh my he got junk marks after so much time has lapsed. Then the surprise, won't give it away.
This is just a little too weak to work with hobby materials like thin plastics or woods and it is too slow. But still very impressive project and if you needed to make stuff from foam, worth looking in too. The results he had were pretty remarkable! Thanks I enjoyed watching that.
I agree John. Something a little stronger than the Lego in terms of stepper motors and perhaps that size or a little bigger, but not made out of iron or galvanized pipe as in the instructable video. We want something that will look OK on the desktop in a house or apartment and not meant for workshop as his iron one. We can all iron out the design later and perhaps come up with multiple designs that users can build then we can evaluate them.
I added a poll to keep count of those interested and to see if we get enough people to go forward.
John, I just wanted to see if there were enough of us interested in this to work together to learn. There are lots of cool challenges, especially when you want to do low budget. Besides the hardware and controllers, you have electronics and of course the programs. Then with a cnc machine you can make parts for anything you are interested in, from home repair items to robots( my final interest on this road ).
I started watching some nice online video courses and will wait a week to see what happens in interest. If not will go it alone.
To tell you the truth, I feel frustrated as a programmer right now. It is an exciting time hardware and device wise, but there are so many directions that one can go and to work on the type of things I want to, which is 3D engines, tools and games. I don't want to work years on a platform that will be dead by the time I finish. I finally started learning the windows api and now see that it will end as it should have after XP.
Android is not what I thought it was going to be. It is neat, but not what I expected. I thought it would be like the old days, cool hardware with a small fast OS and I was hoping it would have a built in programming language with hardware compiler in the device. Since firmware is so easy to update anymore, as Android does all the time, this seemed like such a no brainer to me. But to have to use a desktop device, transfer your app to the device etc... it is crazy. And until voice techology is as it is in Star Trek, you need a physical keyboard and mouse along with a touchscreen.
Anyways, I thought I would use this time while things sort themselves out to learn other things that have been a dream since I was a kid.
Here is a toy designer that must grown up like me, having a toy and seeing all the missed opportunities that the toy should have had and doing something about it now that he can :)
http://www.youtube.com/watch?v=t_AqXCw1SYs
Petr Schreiber
17-02-2012, 09:49
Kent,
I wish I had more knowledge in electronics, I would join your project immediately :)
The walking robot is very well done, I like the smooth walk movement.
I completely agree that we are living in exciting times, when really almost everything is possible. Even the low power hardware is very strong, libraries for almost everything exist... I keep my fingers crossed you manage to find buddies for your CNC project, working on something in team of "compatible persons" is always great experience.
I wouldn't worry too much about your tools becoming obsolete, as long as it is hobby project. It seems even big beasts do not care that much - for example Siemens still uses DDE technology for automation in their automated lines... (yes, it is pre COM, pre OLE stuff)
Petr
The wife is bitching you spend too much time in the shed so the compermise is bring it indoors and build miniture CNC machines in your office where your wife can keep an eye on you.
Based on the door handle/lock, shelving and other room attributes, this guy is filmining this from an activity room in a mental hospital.
John I like your unique sense of humor.
Kent,
I wish I had more knowledge in electronics, I would join your project immediately :)
The walking robot is very well done, I like the smooth walk movement.
I completely agree that we are living in exciting times, when really almost everything is possible. Even the low power hardware is very strong, libraries for almost everything exist... I keep my fingers crossed you manage to find buddies for your CNC project, working on something in team of "compatible persons" is always great experience.
I wouldn't worry too much about your tools becoming obsolete, as long as it is hobby project. It seems even big beasts do not care that much - for example Siemens still uses DDE technology for automation in their automated lines... (yes, it is pre COM, pre OLE stuff)
Petr
Thanks for the encouraging words Petr. I know you have your hands full, that is why I didn't bother you privately via email about it :)
I've been visiting the Instructables Site for some time Kent & regularly receive an email from them featuring new projects. I don't know if you've already seen it but today they were focusing on a Homemade Wood CNC Router (http://www.instructables.com/id/How-to-Make-a-Homemade-2x4-Wood-CNC-Router/).
@Matthew, thanks. I have been watching all the tutorials I can. I don't have many tools, just a drill, hammer, pliers and screwdrivers And very limited space to work. So my first build is going to be a very cheap one to see if I can get the electronics and mechanical parts going. I am even thinking of using a small cardboard box for my frame, just to give you an idea :) I am going to buy that $11 rotary tool (http://www.harborfreight.com/80-piece-rotary-tool-kit-97626.html) from harbor freight this week and see what sort of force I need to hold it and to push it cutting the plastic material I have a lot of at home (my blue plastic pill monthly dispenser (http://www.packagingdigest.com/photo/294/294642-MeadWestvaco_Shellpak_packaging.jpg)).
@John, they start around $500 and go up into the thousands after that. Even the parts for building are quite expensive. I always wondered why the 3D printers cost so much ~$2,000.00 , they are basically a CNC with an additive operation, that is adding material instead of taking away as a regular CNC is, which is subtractive. This first one is going to be under $100, that is my goal including the rotary tool.
Here is a nice article, drawings and video giving a good picture of how to use a microcontroller, step driver and the motor. However, when you add up the cost for this method, times 3 for each axis it gets expensive really quickly. So I am still looking for simpler lower cost solutions.
http://bildr.org/2011/06/easydriver/
I will put links to parts I found as ideas here. These are just for thinking and evaluating. No purchases on them yet.
I saw these looking for ideas at home depot today. I think these will make great platform material for the CNC machine. With all those holes it will be easy to hold down smaller pieces to cut etc.
http://www.homedepot.com/h_d1/N-5yc1v/R-202249707/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=interconnecting%20peg%20board&storeId=10051#BVRRWidgetID
The cheapest material, besides cardboard boxes around the house, to build with I found is PVC piping and connectors. I did put a 3/4" T connector on 1/2" pipe and it slid easily on it.
1 or 2 of these should be all you need with some connectors I would think to build the chassis.
http://www.homedepot.com/Plumbing-Pipes-Fittings-Valves/h_d1/N-25ecodZ5yc1vZbqpfZ12kx/R-100348471/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=1/2%22%20pvc%20pipe&storeId=10051
Also, Lead Screws used in linear motion are expensive. I found threaded rod, again lot cheaper. I guess the diameter we need will be based on the stepper motor we get.
http://www.homedepot.com/h_d1/N-5yc1v/R-100337593/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=threded%20rod&storeId=10051
I went last evening to Harbor Freight (http://www.harborfreight.com/) and bought the $11 rotary tool and 80 pieces. Tonight I tested them.
First, the rotary tool is nice and small. It is very light and would be perfect for an apartment physically in size and weight. It runs at a constant 16,000 rpm, but it does so relatively quietly.
I could run this late at night and not worry about my apartment neighbors hearing me. However, as soon as I touched the plastic to cut, it became very loud. It vibrated the piece I was cutting and the table it was on. It made a tremendous buzzing sound. I went and brought in a silicon heat shield pad from the kitchen. This cut the vibration on the table to near zero, but the vibration from the plastic being cut was still very loud.
So the sound alone killed this project for me as far as a subtractive cnc process machine. I was hoping to get by with this small tool. And as I said, the noise from the tool running alone (no cutting) was even lower than I could have hoped for. I tried both a burr bit and then a cutting disk. Both were loud.
In addition to the sound, the plastic was melting, as I could smell it and later saw it stuck to the burr bit as you will see in the picture. No plastic stuck to the cutting wheel, but the cutting wheel is not what I wanted to use.
I don't know if the bad cuts you will see are from my inexperience with never using a rotary tool or from the plastic melting in the process.
I still want to build the machine that will be a cnc with at least 3 axis motion. I can always mount a better rotary tool in the future where noise is not an issue. Or I could eventually make it an additive cnc machine(3D Printer).
7819
This is a good deal if you have a serial or parallel port on your computer to talk to the device.
http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&catId=293&item=250987621374
John, wow that looks good. I will look more into it tonight.
Update: I read and reread the post. It looks like you still need to add motor drivers. It doesn't say just 5 motors, but: "It can connection 5 drivers and control 5 motors in the same time;"
I tried to zoom in on the photo to see which chips there were using to read up on them, but I couldn't make out what they said. Also I converted the pound to dollars and it comes out with shipping to around $24.
The 4 pin connections for each motor do however look like bipolar 4 wire stepper motor connectors, so it is a toss up for me at the moment.
For getting into microcontrollers and learning, this kit I really like. You start with the core chip and build up. So you learn better than starting with an arduino that has lots of stuff already.
I would add it to our possible kit list.
$80
http://www.nerdkits.com/kits/
Update: it doesn't come with motors as I had thought. In addition, I couldn't find too many good tutorials on using it to control stepper motors, other than that the reviews were good.
Will keep searching for a learning microcontroller kit that comes with stepper motors to learn with.
This is impressive in that someone figured out how to do this. Too tedious for anything other than a technical demo, but still it really shows how this stuff works(3D printing)
http://www.youtube.com/watch?v=2nbtZOolSIY
John, wow that looks good. I will look more into it tonight.
Update: I read and reread the post. It looks like you still need to add motor drivers. It doesn't say just 5 motors, but: "It can connection 5 drivers and control 5 motors in the same time;"
I tried to zoom in on the photo to see which chips there were using to read up on them, but I couldn't make out what they said. Also I converted the pound to dollars and it comes out with shipping to around $24.
The 4 pin connections for each motor do however look like bipolar 4 wire stepper motor connectors, so it is a toss up for me at the moment.
Found the board on youtube. The usb is only for voltage, you need the parallel port to send data. Also he says the axis go to a driver and not a motor.
http://www.youtube.com/watch?v=0D2uYMVrglw&feature=related
Michael Clease
22-02-2012, 10:59
This could be a more simple approach if you could get a cutting tool that is light enough. (A motor strapped at the end of arm with a drill bit coupled to it ??)
(http://www.iwantoneofthose.com/10427343.html)http://www.maplin.co.uk/robotic-arm-kit-with-usb-pc-interface-266257?c=froogle&u=266257&t=module
this might help
http://luckylarry.co.uk/arduino-projects/arduino-modifying-a-robot-arm/ (http://luckylarry.co.uk/arduino-projects/arduino-modifying-a-robot-arm/)
http://www.linuxquestions.org/questions/programming-9/c-code-for-maplin-usb-robot-arm-851033/
and this is just cool..
http://www.iwantoneofthose.com/10427343.html
Thanks Michael. Those are the kind of things I want to get into in the future and build from scratch. I wanted to make the cnc to build parts for robots and other projects that might come up.
This guys amazing robot arm project, it is impressive!
http://www.youtube.com/watch?v=008ziJ0OIgE
Interesting video about stepper vs servos. Servos have advantages, as long as you have an encoder.
http://www.youtube.com/watch?v=mAObZa_PE_8&feature=related
Michael Clease
22-02-2012, 12:11
Kent dont get too hung up on motorised tables using a robot arm with a object thats not moving its more like the expensive cnc machines (i know they use a combination of both).
Perhaps fix the cutting tool and move the object on the robot arm.....hmmm
I got one of these arms yesterday and will be using it to machine parts for a table.
Here is an example of the tables I use at work, one is using motors with gearboxes(nylon drive wheels) and the other is stepper motors.
Congrats on getting your robot arm Michael. Hope you have fun using and also making parts for your table. Can't wait to hear all about how it goes.
Thanks for the photos also of your machines at work. It is nice to see sharp photos like that and of different ideas.
I went last evening to Harbor Freight (http://www.harborfreight.com/) and bought the $11 rotary tool and 80 pieces. Tonight I tested them.
First, the rotary tool is nice and small. It is very light and would be perfect for an apartment physically in size and weight. It runs at a constant 16,000 rpm, but it does so relatively quietly.
I could run this late at night and not worry about my apartment neighbors hearing me. However, as soon as I touched the plastic to cut, it became very loud. It vibrated the piece I was cutting and the table it was on. It made a tremendous buzzing sound. I went and brought in a silicon heat shield pad from the kitchen. This cut the vibration on the table to near zero, but the vibration from the plastic being cut was still very loud.
...]
I did some more research on bits for rotary tools and instead of looking at what a burr bit does, I did a search on google images for a rotary tool cutting bit (https://www.google.com/search?tbm=isch&hl=en&source=hp&biw=1920&bih=1075&gbv=2&oq=rotary+tool+cutting+bit+&aq=f&aqi=&gs_sm=12&gs_upl=1627l1627l0l2751l1l1l0l0l0l0l71l71l1l1l0&q=rotary%20tool%20cutting%20bit&orq=rotary+tool+cutting+bit+#hl=en&safe=off&gbv=2&tbm=isch&sa=1&q=a+rotary+tool+cutting+bit&pbx=1&oq=a+rotary+tool+cutting+bit&aq=f&aqi=&aql=&gs_sm=3&gs_upl=29821l30029l0l30483l2l2l0l0l0l0l86l159l2l2l0&bav=on.2,or.r_gc.r_pw.r_cp.r_qf.,cf.osb&fp=3a3bb46ad1e6f020&biw=1920&bih=1075)and saw that it brought up pictures of bits that looked more like drill bits.
So I tried a bit like that in addition to cutting the plastic with snips to isolate it into a single layer. Using the single layer plastic without the air gap really cut down on the noise. It was still too much noise to use in the evening with neighbors around, but it was about only 1/3 of what it was last night in the short test. The plastic still put out a burning smell, but it did not stick to the bit as it did to the burr bit. While I could drill and scratch the plastic with the power of this machine. It does not have enough torque to be used for milling. As I had mentioned it is small and lightweight so I am not too surprised. I think this is made more for polishing and perhaps sanding very small items.
Even this little rotary tool needed a lot of force to push it around the plastic and keep it in control, much more than I ever thought it would.
update: Just found this nice article about rotary tools for cnc machines. He has tried most of what he writes about and he even mentions the low cost one I bought to test.
http://www.jcopro.net/2011/12/02/what-is-the-best-dremel-tool-spindle-for-your-cnc-router/
Here is a site where a dremel is used in a home made cnc machine. His cuts are not as good as I would like either. It could be the bit he was using. What do you guys think?
http://www.lirtex.com/robotics/diy-cnc-machine/
I went and bought a piece of pine today to try with the $11 rotary tool. Good news it worked, see attached photo. You can see all the dust just from this small amount of work. So some sort of dust collection system should be thought about for the design of the cnc. Also for the sound, although this is probably as quiet as any cnc can be with this tool and wood, it might be an idea to put it into an sound insulated box at some time. I guess this is more critical for late night guys like me who live in apartments. For daytime use, the sound would be no problem to anyone.
While I was at the store for the wood, I was thinking of buying a name brand cutting bit to see if that also made a difference. Boy was I shocked!! A single lowest cost Dremel cutting bit cost 175% more than my rotary tool with 80 accessories total! The RotoZip had much better prices on their bits, you could buy a pack of cutting bits for the price of a single Dremel bit.
7823
update:
I used the 2 smallest cutting bits in my kit, a 1mm and 2.3mm and both worked the best. Also the sound reduced with these thinner bits. I would say the sound is at or slightly lower now, than running an electric vacuum cleaner. You need to cut in thin depths a 1/4 mm or less.
So if we used a 1/4 -20 rod (http://www.lowes.com/pd_44540-37672-11007.0_4294753696+5003694__?productId=3128759&Ns=p_product_price|0&pl=1¤tURL=%2Fpl_1%2B5_4294753696%2B5003694__%3FNs%3Dp_product_price%7C0&facetInfo=$1%20-%20$5), that is .25 diameter and 20 revolutions per inch. A normal stepper motor is 200 steps per revolution, and if we use the normal 8 steps that is 20 x 200 x 8 = 32,000 steps per inch. (1/32 000) in = 0.00079375 mm about 315 steps to move 0.25 mm
Michael, found this you might find interesting. To control robot arm with very low cost Texas Instruments microcontroller kit:
http://e2e.ti.com/group/msp430launchpad/m/project/534532.aspx
I narrowed down the starting electronics kits that look interesting. We can decide which we all like.
I think we can skip the basic electronics kits and start with a microcontroller kit and get going faster. If we are lost we can always go and start with a simpler kit.
In order of price:
$4.30 Texas Instruments http://processors.wiki.ti.com/index.php/MSP430_LaunchPad_(MSP-EXP430G2) what's in the box video: http://www.youtube.com/watch?v=RVHGjgkFPlU
$29.95 Arduino Uno http://arduino.cc/en/Main/ArduinoBoardUno or any of the starter kits http://www.sparkfun.com/categories/103
$79.99 Nerd Kits http://www.nerdkits.com/kits/
Arduino and Nerd Kits use ATMEL AVR chips. The arduino has a better chip. All three seem to have nice tools and websites to learn from.
I will probably buy all of these sooner or later to play with at these prices. I think ATMEL chips seem to be the hobbyists choice by far as of today.
By far Arduino has the most info and projects out there that I have seen.
Do you guys have any others you want to be added to the list?
Michael Clease
23-02-2012, 15:56
I use PicBasic with PicKit 2 (http://uk.farnell.com/microchip/pg164120/programmer-pickit-2/dp/9847170) for the programmer, I find it very simple to use and the only thing I cant seem to get working properly is one wire single shot memory DS2502.
Have a look at Swordfish (http://www.sfcompiler.co.uk/swordfish/) i haven't done anything with it although I installed it a while back.
I looked hard at PIC as they have lots of stuff and they were the first microcontrollers I ran across years back when thinking about getting into this stuff, but then didn't.
In fact, I found more websites with tutorials on running stepper motos on PIC than any other. The only reason I didn't put them on the list was in many comparisons they kept mentioning that the AVR chips were more modern and what you learned would go longer these days. When you read the flame wars about pic vs avr it is obvious both chips have a huge fan base and great support.
Thanks for your links as they are in the UK. Here in the States, Parallax is a big company with many great PIC products.
http://www.parallax.com/
So these are worth looking too.
I ordered the nerdkit today. For trying to learn this stuff, it was a good fit for me. I plan on trying all of these kits eventually, as they seem like a good value for the fun they can provide along with education.
REDEBOLT
24-02-2012, 12:10
http://www.pcworld.com/article/250554/3dprinted_dinosaur_robots_are_coming_hopefully_wont_scare_small_children.html?tk=out
Bob
http://www.pcworld.com/article/250554/3dprinted_dinosaur_robots_are_coming_hopefully_wont_scare_small_children.html?tk=out
Bob
That is neat. Did a search on youtube and found this video.
http://www.youtube.com/watch?v=kOCW1uQPOJQ
I was really impressed at how quickly my order came. I didn't expect it to arrive till Monday or Tuesday, but it arrived Saturday.
There is not much to it. I didn't add up the cost of the items that came with it yet, but not too much comes with it. You get an account number that allows you into a member's only area and from there you download the manual, datasheets and the programming software. There are additional explanations and projects on the website.
The 82 page manual reads like you are reading very short notes written by a very smart university student. There is minimal explanation and if I had not been reading about electronics and watching videos online, I would be totally lost. So this is really not for beginners in my opinion. I like to first read through the manual before attempting to make anything and that is the stage where I am at now.
You have about 23 pages of stuff to read before getting into putting anything together. You then get instructions on putting the kit together and running the initial test to make sure everything is working, that takes you to page 32 of the manual. The next 5 to 6 pages is troubleshooting and hooking up the usb cable.
The good thing about this kit is they do emphasize they want you to learn and to ask for help via email if you need it. Also they don't let you just plug in a usb cable, you actually have to attach each lead wire at the board side to the breadboard. This is their philosophy which is you are not just learning electronics, you are learning electronic engineering.
In watching the video tutorials on youtube, I can see the difference. Putting electronics together from schematics is what I thought it was all about, but that is just doing electronics. That in itself is pretty daunting, but it is nothing compared to engineering and designing your own circuits. For this it is all math and you have to take in to consideration all voltages, current and tolerances for each part and make sure they match up. This kit sort of encourages you by asking you to experiment on your own and to figure things out. They do have a support forum.
I will write another review after building the kit and seeing if I can program it. My recommendation, without making anything yet, is I would hold off on purchasing this kit if you are totally new to electronics. Or expect to augment this kit with lots of external reading to supplement it. Is it worth the price, I am sure over time it is. Initially I would say no, based on what you get. I say overtime because they are adding projects and do have a nice support forum and electronic newsletter and are willing to answer your emails. So that alone would be worth the cost over time.
I went back to harbor freight Friday night. I was able to find one of the knowledgeable guys there free, for a minute, so I told him about this project and that I had bought the $11 rotary tool. I told him I could only use 2 of the bits to do milling. He told me that I needed a cutting drill bit, also known as a drill saw bit or what is known as a milling bit. He showed me a 3 pack and in the pack only 1 size would fit my rotary tool. But compared to dremel and rotozip bits, this 3 pack was cheap. So I bought it and indeed the bit does make a difference.
So look for deals on these kind of bits for your rotary tool. Here is a page with a good explanation (http://cncmentor.com/blog/2011/07/12/endmill/). You want one that can drill and cut.
Well, I got the nerdkit put together tonight. I was very happy after all the tedious work that it works!! Very satisfying feeling. But in doing a lot of associative extra reading and video viewing on my own to supplement this kit, I would not recommend it to any of you. I see that the arduino and pic communities have so much more to offer in a more usable manner.
I was willing to try this kit and do all the work, but I thought it would have lots of info and educational value. It does not. I am sure, as I wrote in the previous review that it probably will. But it is not there at the start when you need it.
What really surprised me besides all that the microcontroller can do is the crystal clock. It is just a quartz crystal in a tin can basically and when it gets a current it vibrates at a fixed frequence, in this case the speed of the cpu for the microcontroller. They say it can do 14 million plus operations per second. Pretty amazing.
Attached is a photo of my kit put together. I went and identified all the components.
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It seems microcontrollers were designed for serial and parallel ports. With parallel ports you can drive motors and things from your pc without a microcontroller, the pc acts as the controller. To use USB, somewhere in the chain there is a usb to serial converter. You have to install a driver for the usb and it shows up in device manager as a serial port and in the system tray as an usb device. In my kit this usb to serial is built into the usb cable. In others, it is on the controller board somewhere. So far in the 2 programs that I uploaded to the micrcontroller, you use bitwise operations a lot and work with the registers on chip. These are programs I just copied from the manual, with no understanding yet.
I am sorry I can't share code or much detailed info as they copyrighted the material heavily. You can't share even for non-profit or educational use. Another reason I don't like this kit. Parallax(PIC) is open source as is Arduino.
Just wanted to post that I am still researching and studying on this project. If I wanted to throw money into it, there is a lot of info on buying linear motion systems, stepper motor controllers etc. But I want to make this as low cost as possible and a real home brew project, so it is going slow, but lots of fun.
John, I am happy Athena has responded well to her physical therapy. The litegait looks like quite a machine. I am sure you are all excited she is coming home after such a long time.
I am speaking without knowing anything about your house's structure. But instead of building a platform, you might want to just go into the joists in your ceiling and rig up a support system like that. You would go into 2 joists or 3 if you want a third suspender coming down the back and have it centered above a treadmill.
I also found this. Looks like a great device for a bargain price. http://www.especialneeds.com/gross-motor-skills-bouncing-health-bounce-trampoline.html She would not use it for bouncing of course, but for balance strength build up and exercise.
John, I don't think you need any motors. From the exciting photo of Athena standing with a walker, it looks like she just needs a safety system to support her in case she starts to fall.
You could just run steel cables 2 in parallel (orange) and then a third cable (green) perpendicularly to the other 2 (see drawing). Then Athena could be safety harnessed to this third cable (blue) giving her total free x y movement.
Inside, I would make sure to eye bolt into studs in the walls. Better yet, put a 2x4 between 2 wall studs and put the eye bolt into that in new between stud. For the harness connection to the third cable(green) you would need a strong swivel connector giving Athena 360 turning ability. If you could find a swivel connection that can disconnect quickly, then you could have this sort of rig in the rooms she would like to use. The parts for an entire room are probably under $50.
Outside you could use poles to support the 2 parallel cables giving her outside access with safety.
The (green) cable would move left to right (lets call this X movement) in the room along the (orange) cables. The (blue) harness would move in the perpendicular direction (Y axis) along the (green) cable. With a swivel connection she could also rotate freely.
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Your post was relevant to using motors and control systems, besides it came with good news of Athena's progress to boot!
I ordered the nerdkit today. For trying to learn this stuff, it was a good fit for me. I plan on trying all of these kits eventually, as they seem like a good value for the fun they can provide along with education.
http://www.routercenter.com/
One thing I realized in playing with my NerdKit is that there is so much more to electronics than just putting things together. You really need to become an electrical/electronics engineer to really use the nerdkit.
I found myself wandering off to reading up on things way over my head and too much new stuff to absorb and retain.
The Arduino is more for us who want to use this technology without having to become engineers.
But since my end goal was to make a cnc to make robotics, the world has changed so much since my first post that now you can get robot kits and get right to the fun stuff without having to make everything by hand.
I don't mean the simple hex bug like robots but robots with motion, sensors and communications. Really no need to build a lab anymore if you want to get into this stuff.
Here are just a few.
http://adafruit.com/products/1006
http://kits.makezine.com/category/robotics/ page 2 has some cool stuff too.
https://www.sparkfun.com/products/11074