skaako

Wow, those are some big wheels. Very cool. There must be a great deal of torsion for the axles.

I'm getting my very first NXT set this weekend.... don't laugh : ) If i have the time i'll see what sort of interfacing i can do with it. I'm guessing its quite simple though as most of the more advanced sensors are just I2C based. I like the potential of it having a built in RS485 port, that could be fun too. I wonder if anybody has tried to interface the Nintendo Wii Remote sensors to it yet, as they are I2C based. The Wii Remote has a nice IR Tracking Sensor module in it that i have seen people play with, can track about 4 IR Emitters if i remember right. The HiTechnic sensors do look quite nice, its the price that puts me off though. Its good to see that TLG actually sell their stuff on the Lego website. Mike

If you are handy with a soldering iron, it doesn't take too much to build. As for the cost its hard for me to tell, the IC's were leftovers from an order, usually only a few dollars i think. The IR receiver and IR LED were from an old VCR or something, they have been sitting in my box for a long time. All the discreet components are cheap, the connector was from the box, the only thing i had to buy was the board, which was $2NZD. I guess if anyone was really interested i could send a pre-programmed PIC at cost. Or email me for the HEX file. Here is the schematic also. As you can see, the 16F628A is a bit of an overkill. Mike

£6 thats amazing. I thought i was getting a good deal when i paid $95NZD for mine : )

Cool, please let me know how you get on with that, sounds very interesting. What sort of things do you use your CLI's for? Mike

Wow, 9 of them. Thats impressive, it would be fun to see how many you could use at one time. Maybe something like a com port multiplexer would do the trick. The thing that hinders me from buying overseas is the cost in getting it here to NZ. Actually i still count electronics as a hobby as it is not my main job, but i have made or taken part in developing commercial/industrial products. Mike

I wish i had more than one of these, then i could experiment with controlling multiple CLI's. They seem to be as rare as hens teeth to get hold of now.

Hi Mark, Thanks for making that schematic. I did use it during making my IR tower to give me an understanding of how the actual Lego IR tower worked. I was contemplating whether or not to build the carrier signal generator with a NAND IC like the original Lego tower or with a 555 timer, then went with a microcontroller as i could then tweak the frequency easier, required less external components, and i could easily invert the output if required. Also i had a few of these chips lying around handy. From having a quick look inside the USB Tower i had use of, it looked very similar to your schematic for the serial version, it made me think if the USB to Serial converter was built into the USB plug, as the plug seems large enough to house it. Mike

Yep, i totally agree. Thats why i stick with good ole PDIP : )

Hi again, I had planned on using the PIC18F2550 board shown in my last post on the Dacta CLI topic http://www.eurobricks.com/forum/index.php?showtopic=32749 as a USB to serial adapter for the RF module, i have used it in this way for other projects and it works quite well. It has a windows driver that detects it as a com port so its nice and simple to interface with. I will either do it this way or just use a standard USB to serial adapter as my laptop does not have a serial port. Mike

Thanks for the interest, i'll let you know how i get on. My robot is nothing fancy though, it is just the crawler track one from the book. The wireless modules i use are the Hope HM-TR, they are very robust and i use them even in commercial projects. Another reason is that they are easy to get hold of here and are not very expensive, around 15USD. I laughed with my friend about using a high power unit, should get over 3km, only as i joke, i dont need that much range. These modules are produced by a number of manufacturers, they are just known as RS232 Transceivers, but the one in the picture does not have an onboard RS232 IC. I'll have to draw up a schematic sometime soon and post it as i made it up as i was going along, first on a breadboard then onto the prototype board in the picture. Mike

Hi all, After getting my first RCX 2.0 kit for a bargain due to the fact it was missing the IR tower and a few miscellaneous pieces, i went about building a serial port tower. This was due to the fact after looking locally online after a month i gave up, and my friend needed the USB Tower that i was borrowing back. After looking for some plans online i didn't have much luck and nothing that i could build with the parts i had on hand. I realized with the help of some very informative sites that the IR tower is just basically a serial port at 2400 baud 8 data bits and odd parity. Also i found it uses a standard 38kHz as the carrier frequency. So for the IR receiver is a simple circuit fed into an RX line of the RS233A IC. For the transmitter was a bit more tricky, so a small program on the PIC generates a 38kHz carrier frequency, then a TX line from the RS233A is fed into an input of the PIC, the program uses this to modulate the 38kHz carrier. The IR LED is driven directly from the PIC at about 15mA. Only 4 pins of this IC are used so a smaller chip would do the job. Now.. many sites state that the RTS, CTS pins of the Tower are joined so that the program recognizes that the tower is present. I did join these pins at first and it worked perfectly, so i disconnected them and it still worked, even carrying out a firmware update in Robolab 2.5.4. So maybe only the earlier versions of the software checked for this. So now i had made my IR Tower the next step which i had planned earlier was to make it wireless. I like using the remote in Bricx to control my robot but if i turned it around.... no more communications. So with a header added to the board a and a few extra wires i added an RF transceiver module. With one attached to the com port of the computer now i will be able to drive the robot all round the house without worry. I have only bench tested it as yet, but the next fine weekend we get i'll take it to the park for a trial. I'm expecting around a 300m LOS range, these modules i have managed to get 350m max at 9600 baud so 300m at 2400 shouldn't be too much to ask. I can post a schematic/HEX file if anyone is interested. Now the only thing is... my friend wants one too : ) Mike

I finally took a picture of how i can control the interface with a microcontroller. I still do not personally have a use for it, but i guess a setup like this might be handy for people who take them to shows etc. It does not require a computer connected to the interface, the USB is only to provide the 5V via a 230-5V USB adapter. I guess now its more like a big RCX. Mike

I tried the link but it seemed to be dead. Yes, this website was where i gathered all the information on the protocol, it had everything i needed to get started. I noticed the same thing with the dll when i tested it, i think it might just be overflowing the uart buffer or something along those lines. Mike

Yep, thats the reason. I have never seen a 9V crossing for sale on the NZ auction site, and to get things sent from overseas costs quite a bit. So i bought a few boxes of RC track at $20NZD each, i do not count the curved track in the cost as i have way too much. So thats $5NZD for 2 straights or about 2.50 Euro i think. Mike

I was a bit reluctant to cut up some straights but then i saw some cool layouts that used the crossover so i had to make one. I did it a bit different than the tutorial but the final result was how i wanted it. Works great with 9V. Mike

Hi there, If you don't mind a non lego solution you could try something like i have made and use to motorize my points. Theres a few more pictures in that folder of the motor etc. Advantages: One of the smallest footprints you will find for a points motor. Motors can be acquired free from most old CDROM drives. Can be disguised easily as a track-side cabinet. Disadvantages: Not 100% Lego components. You do have to modify the point to reduce friction as these motors have little torque. I cannot take credit for using this type of motor as i had got the idea from someone else. I managed to find the original article at http://www.freelug.org/article.php3?id_article=507 by Xavier Viallefont. I pulse the motor for about a tenth of a second at 12 volts and it works just fine, and can run on as low as 5 volts if required. Mike

Hi there, It is possible to use an adapter that is male-male or female-female depending on what you need. If you have the parts you can make a cable quickly, you only need to wire 3 pins. TX-RX RX-TX and GND-GND. Or you could make this as an adaptor and just use it with a straight through cable. When i bought mine secondhand mine too came with the mac stuff, so i just modified that cable. Mike

Hi Mark, thanks also for this information. I dont have any of these motors yet to try, but does this mean if they are run at a full 9V they may even outperform the original 9V train motor? Mike

Hi there, I think i'll stick with my Dacta Control Lab for the time being, i like the number of outputs it has, plus its easy to write programs for. For the Dacta i use vb or liberty basic. I have only recently got a RCX set to 'play' with and i have found NQC quite simple to use using Bricx to write and compile, if anyone can suggest something better i would most appreciate it. The only problem now is that i want an NXT. Mike

Thanks for the link. Now hopefully i can find a supplier that can get them here in New Zealand.

Hi, I have been experimenting with a standard lego wheelset for use as a power pickup to save on using an old 9V motor. I do need to machine some wheels with an axle that is isolated. Im just trying to find the best way of doing this at the moment. I want something that is relativly easy to put togeather, and can last and be reliable. Also this way gives the flexibility of wheel configurations and also can be produced at any time in the forseeable future. Mike

Hi, Yes you sure can, just hit the run button on the menu and away it goes, No need to compile at all. Actually i very rarely use the compiler, only when i have finished a project. Mike

Hi Sal, The only thing stopping me from looking around online is that to get it sent here to New Zealand usually makes it too expensive. Model train motors, though they do have dual output shafts are usually the incorrect dimensions to fit in the 9V train motor casing. Also finding one with the right size gears would be very difficult. Thanks. Mike

Hi, Actually the DC motor in the 9V train motor is quite a standard size. But yes, to find one with a gear on each end of the shaft is more difficult, i havnt found one yet. But i did find a 12V motor of the same size from a car central locking mechanism, it had quite a long worm gear on it and when i removed it from the shaft, the shaft too was quite long. Now i'm not sure if this works for different motors but i managed to open the motor and removed the shaft and rotor. Then placing the rotor on a rod with a hole big enough for the shaft to fit through, i forced the rotor along the shaft more by using a press. Then i reassembled the motor, put the gears on from an old 9V motor and cut the shafts to length. Now i can run it on 12V and it has quite a noticeable amount of power. This was quite a time consuming and frustrating process, but the end result was what i had hoped. All the motors i have seen have the end of the shaft visible from a small hole at the rear of the motor, that way if the shaft can be pushed through, it should be able to be converted. I havn't ever seen a motor with exactly the same size gear as the train motor, so if anyone has an burnt out one (just the DC motor) i would be interested as i dont have any more dead ones to take the gears off. Thanks Mike