Latest Update….

Started working on the printer project a little more, and worked great until about 3 days when my main computer [laptop really] stopped working correctly, and am now working to fix it to bring back life to my computer and then the program itself, along with the printer….  Maybe I’ll work on a similar program again in Labview until I can get the original Labview file off the laptop.

Fun, fun, fun.

It did work really well and even got the printer to print better quality on its own, without human assistance, with faster programming and even Bluetooth worked with this program once I found and fixed the bugs…

 

As far as that goes is as far as I can go for now. Maybe another update in a little while, maybe even a YouTube update…

Diagnostics Program

This is a small program that runs on the NXT. Its very simple, but is meant to be helpful. You will probably need LV 7.1  and the toolkit and th drivers in the least to put this onto the NXT.

Will upload diagnostics.rxe version for easy download, but you will need good job.rso on-board.

http://www.mediafire.com/?do4di7i6a2t62 Link to file folder.

Hope this helps for those who need it, or just for a fun mini-project. Tell me what you think. Post comments with ideas…, links to new files too…

Problems and inspiration.

Today I went to a FRC. It was fun, and I joined a team only 3 weeks earlier, and hopefully things will turn out good. So far they want me to be their lead programmer, and it sounds like fun. Today’s match was a ton of fun and it is a great place to meet people that love robotics. I think these robots are more fun than your typical robotics, and it beats the FLL by 100 times better. These robots make your Lego NXT sets look like toys [well, lego’s are toys aren’t they?]

They seem to have a lot of fun and it included having the best food I’ve had at a robotics event – a group was fundraising for their robotics team and was selling these great burgers that were amazing [partially because they were cooked on a propane stove] and it was just a fun experience.

 

On the bad side, I found out that port A on my newer NXT no longer works – the motor output is fried. The rotation sensor seems to work OK though… Probaly something I should report to Lego.

I could probably take it apart and find the problem, but there’s no point. I’m probably better off making it into a full rotation port and build a rotation sensor so that I can do it without a huge motor. I looked up the specs, and it’s a simple trigger system

1 degree equals this en-emulated into the two signal wires:

0 0

0 1

1 1

1 0

And opposite order for the other direction.

I tried making one with light resistors, but I can’t get it to work. Probably better off using them as light sensors. I feel that light sensors reflecting off an object is more accurate at telling distance than the Ultrasonic, which works best in port 4 than any other [partially by the raised transfer speed/communication]

I’m thinking I’ll work some more on the printer.. make a skid steer out of the other robot for now, at least it only takes 2 motors, and I could use the prototype board to make a third motor port…

 

There were a lot of cool ideas at the FRC and am considering what to build out of the ideas I saw there,n I could really improve my robot with their ideas.

Printer update! Surprise Enclosed!

OK. So a friend of mine and I got together last weekend and we totally rebuilt the printer. It’s design is very similar, and I’m sure we used many the same parts, but now we have a more functional robot. While it is practically impossible to get it to feed paper into it correctly, we finally got it to work. We gave up dots and complex programs and it paid off. We can draw lines on the paper now instead of lousy dots that the stupid ink-jets that take three hours to print. We can only draw one line at a time, but it works much nicer. Found the camera so pics to follow.

Other project:

Centrifugal Force Air Compressor:

This is a cool project. I was actually trying to make my own GluideWheel or whatever it’s called to connect PF motors as if they were NXT servos with all the rotation sensor stuff. A great idea, but I wanted to build one first, since I have the equip.

Really its not that hard to make a lego NXT motor port rotation sensor. All it is is a group of LED’s and light reactive switches [whatever you call those useful things] and a correct hookup. I hooked up the PF to a NXT port and found that the 2 amps out of the NXT was much better than the 200mA of the battery box, and decided that this motor is practically unstoppable, which when connected to a NXT port, it’s practically that. So I decided to gain centrifugal force and use it to run an air pump geared up from the normal motor, and it worked fine, in fact it went all the way to 47 PSI before it couldn’t kep up with the leaks, and just stayed even. But under the regular battery box hooked up the way it is it would stop at about 10 PSI, hardly enough to move a small piston.

This was a great idea that works amazingly. More tomorrow.

I cannot seem to find my camera, but i have built a walking robot [well, it has front  legs and back wheels, but the legs are what make it go forward, or backwards. It works OK, but i’m sure with a better leg design it would walk more efficiently.

This robot is kinda inefficient, as it takes 2 steps forward and one step back. But it still travels, works better on solid smooth surfaces than, say a rug. It works really well on my mouse pad, which is soft foam with a layer of cloth on top, all a solid piece.  The robot is actually very simple and most of it can be made just by looking at a side view since all the mechanics are on the outside for looks.

It does walk very slowly though, maybe an inch every 3-5 seconds, depending upon the surface.

Pictures to follow if I can find my camera. I took apart the solar panel idea. It worked, but I found that the solar panel charged the battery the first day, and it didn’t really need charging for the next week with the LED output of only 4 led’s…

Program for the solar panel hookup to the NXT and a full schematic will be around soon…

 

Solar Charger Project

I have the basics out for this project. The robot part will be incorporated later.

Right now this is the setup:

solar panel -> battery box -> output

soon it will be:

solar panel -> battery box -> output panel ->output

 

Battery box-> NXT  <-> output panel

 

 

 

 

 

 

 

 

 

 

Two series circuits that are interconnected.

There is more than a SPDT switch in the battery box, but this is for simplicity.

The NXT would be connected to the blue and green wires through an RCX end and 2 cables to Port A and Port 2 The program is done, but it needs to be edited.

Printer + Robot update.

Both robots are now operating seamlessly. I renamed them – Jared [that’s my personal robot, will not be seen very often in JP, unless a dual NXT robot is used] – and – Jared JP [that’s the general purpose robot]

I fixed the screen, and best of all, found that it coldn’t hurt to update the firmware, on the both of them, to 1.31 [one was under 1.29, the other was really unupdated and at 1.05!]

I also fixed a problem where one of the batteries would not function at all. Apparently the one on Jared JP [originally Jared A., the second one I’ve bought intentionally] had totally depleted in about 5 minutes [that’s the normal properties of a Li-on, they last at high voltage really long and then plummet. That’s what this did and took forever to charge, and made a mental note – as soon as its 7 volts – charge it. As soon as it hit 6.9, it just dropped like a rock to 5, where the NXT automatically shut off. It takes a while to get from 5 back to 7.2v.

Printer LDD + photos for your reconstruction if you want to try it. Some of the printer parts are impossible to build in LDD without great difficulty, so I left them out and took pictures of the actual thing.

Problem

Latest problem:

The robot that has been left over for the printer has been sitting a while and when I turned o the NXT, the screen was not working correctly. Via Bricx, I could connect and see that the NXT microchip was indeed sending the normal screen, but the image was halfway down the screen. But after going to get some dinner, and leaving it on, it somehow fixed itself in 10 minutes, and haven’t had any problems [except that I can’t find my battery charger for the NXT power pack]. I think one of my ultrasonic’s are broken beyond repair, so I might have a take-apart of that to see what could be the problem, maybe a loose connection or something… I’ll have to test it again, maybe it just wan’t sending anything…

The solar charger works great now that the sun is out. I actually got above a charge of 1.2 volts in the rechargeable, so that’s really nice [my charger usually leaves them at 1.15v]. The sun looks bright again today, maybe I’ll get a full 1.5v! The NXT agrees with me and putting all six into the robot measures out 7.4v, = 1.23v. Nice.

Now just to find the charger. Sorry that I lost the enthusiasm to build the printer any farther, but I will publish building instructions… Hopefully it has the rack gears in the library of parts…

Square Wheels Robot

I got tired of waiting for the sun to come out to take a video, so I got a little off-track and made a cool project: A robot with square wheels. It looks really weird, but sounds cool as can be, almost like a 5hp engine on idle.

Video:

Preview for Solar Battery Backup Device using Lego Power Functions

There will be photos and video of the project coming soon, but I can tell what I have so far.

I’m taking a shoe-box and converting it into a battery backup. Although I’m only using a power functions battery box filled with 6 rechargeable 2400mAh batteries, creating a total of 7.2v and 14400mAh, it’s only powering LED’s, which use about [according to my research] 10-20mAh. That would amount to [with 20mAh] about 720 hours of light in one charge, with one LED. If I ran LED’s for 8 hours [overnight], then I could run at least 30 LED’s. That would be plenty of light for a room or two… and during the day I could charge them with the solar panel, and use a small power regulator, maybe the NXT, but could be as simple as running a motor while charging in the sun to keep the rechargeable batteries from overcharging. I could run the NXT all night easily on a rechargeable battery pack that I bought for it from Lego Education [a site full of bulk Lego’s!], but I could only trust the power pack and a wall socket with the best power-strip with all sorts of protection for that.

The great thing about Power Functions is the plug. It has 4 wires, as follows:

positive [0v]

variable [the direction of the swich on the battery box or the separate switch uses this to run the motors and lights]

variable [reverse charge of the one directly above for return voltage]

negative [full battery charge, for me, its 7.2v]

Using the two outer ones, I can charge the battery without impairing the ability to run the motor in either direction. This is really useful, although I don’t like the design for the external switch because it doesn’t work independently of the battery pack to send a voltage to the motor or led’s – only the battery pack can use the outer wires, and the motor and switch can only use the inner ones [but the switch, regardless of position, will always send voltage through it on the outer wires. I assume this was used for the Infrared receiver and other parts to work with it, independent of the position of the switches. The good thing is that when you switch the battery pack to the off position, it shuts off all the wires, including the outer wires. This in some places may not be extremely useful, but the use is good here because I can control it better from the external switch anyways… If you really didn’t like it, I’m sure it’s not too hard to take apart the battery box and edit that problem, but I like it in it’s “vanilla” [original] form.

I hope to have pictures out soon, maybe a video too.