Cutting corners to lower cost

[Burf2000]

As some of you know I build large robots, well human size out of Lego and this can use the odd thousand or ten's of thousands of parts

So George is built and I am keeping him but I am planning up to 4 more robots and working out how to this cheaply is giving me a headache

The main issue is having enough electrics. Having a robot doing many things means I need to use Multiply NXTs, or a NXT with PF link / RCX or NXT with a MUX. Then how do you control it? Another NXT? PS2 Sensor? Android device? PC?

Once you get past that issue, what about power packs, motors and then cables (if you use NXT or PF cables your need extension) I think the cabling in George is cost over £60, probably over £90

One of the robots I am building, I am thinking of using RCX's (I have quite a few, cabling is cheap, how loads of motors) however does anyone know if you can use 2 motors per port? I am thinking of cutting cost by using some of my old 9v motors instead PF XL / NXT's.

I am wondering with enough gearing if 2 * 9v geared motors could do the same job as an XL motor (would be slowed down).

It would be nice to put the old motors and RCX's to a use

[Lyichir]

As some of you know I build large robots, well human size out of Lego and this can use the odd thousand or ten's of thousands of parts

So George is built and I am keeping him but I am planning up to 4 more robots and working out how to this cheaply is giving me a headache

The main issue is having enough electrics. Having a robot doing many things means I need to use Multiply NXTs, or a NXT with PF link / RCX or NXT with a MUX. Then how do you control it? Another NXT? PS2 Sensor? Android device? PC?

Once you get past that issue, what about power packs, motors and then cables (if you use NXT or PF cables your need extension) I think the cabling in George is cost over £60, probably over £90

One of the robots I am building, I am thinking of using RCX's (I have quite a few, cabling is cheap, how loads of motors) however does anyone know if you can use 2 motors per port? I am thinking of cutting cost by using some of my old 9v motors instead PF XL / NXT's.

I am wondering with enough gearing if 2 * 9v geared motors could do the same job as an XL motor (would be slowed down).

It would be nice to put the old motors and RCX's to a use

With the RCX you can use two motors per port, but only if you want them to do the same thing at the same time. Or, by rotating the connection, you could make them do opposite things at the same time; for instance, when one turns clockwise the other turns counter-clockwise. But you can't control them independently if they're using the same port.

[Burf2000]

With the RCX you can use two motors per port, but only if you want them to do the same thing at the same time. Or, by rotating the connection, you could make them do opposite things at the same time; for instance, when one turns clockwise the other turns counter-clockwise. But you can't control them independently if they're using the same port.

No thats fine, I was worried that they would suck too much power, like the rcx can't really run the RC motor

[le60head]

I am sure you can use an RCX to power 3 onboard motors ( 1 channel for each). What i was surprised to find out is, that the RCX can send commands to PF remote receivers! It can be done by using the built in IR receiver. This means, that 1 RCX could be the "brains" of your bot, and it can control an additional 4x2 = pf motors via 4 IR receivers set to different channels. Ofcourse, that means powering the PF receivers with an additional power source.

here is the link to the website, where you can see how to do that trick:

My link

I haven't tried it myself, so i have no personal experience in the matter.

Wish you luck with your amazing bots! Keep it up!

[DLuders]

@ Burf2000: Have you seen the Mindsensors.com Multiplexer for NXT Motors? "With this multiplexer, you can connect two additional motors to your NXT.

It also has a pass-through Digital Sensor Port to connect more sensors/multiplexers. (On this sensor port, you can daisy-chain more multiplexers to connect additional motors.)

•Compact, Easy to Integrate Design

•Easy to Program

•Use with NXT and/or Arduino

•Supported in NXT-G, NXC, RobotC, LabVIEW

•Uses external power supply/battery for motors"

[Philo]

No thats fine, I was worried that they would suck too much power, like the rcx can't really run the RC motor

At the bottom of my motors comparison page, I gathered some data about performance of motors on RCX, including curves for two paralleled motors...

[Burf2000]

Oh good man! I am always looking at your site!

[Burf2000]

At the bottom of my motors comparison page, I gathered some data about performance of motors on RCX, including curves for two paralleled motors...

Hey there, have you ever reviewed this motor ?

http://www.bricklink.com/catalogItem.asp?P=bb129