Boxerlego

Looks BIG! How are you going to turn if your using the RC controller. Will you be using TWO RC controllers or will you be using your sacrificing your reverse direction as a way to turn.

Right now I have a 433mhz transmitter. But I've been looking at the 2.4ghz transceivers.

Very interesting. I understand your electrical response for how the Lego servo returns to center. My thoughts were steered towards the mechanical process going on the RC controller for the servo motor to return to center. I just recently watched you test video and 30 seconds into the video you described how when you release the steering wheel on the radio controller is able to center the servo but the radio controller is not in the picture. I watched your first video and the only time I see the servo was able to hold its position is when you use the Trim dial on the controller. My main focus on the microcontroller is the controller part behind all this. When I'm thinking about using a 555 timer to control my servo motor the only way I see how to have a return to center capability for the servo is to have a spring on the controller part. However, using a spring on the steering control removes the servo ability to hold its position when I take my hand off the wheel. I want to have both options on the servo one that can hold a position anywhere I set it and also a option for a return to center function for the servo. So that means if I wanted both options here with a 555 timer I would need a method for switching between the two possible control options for the servo and also have a button that is able to make the servo return to center. Now this is wheres my thinking goes in to realm of microcontrollers and that is being able to program a servo driver with programmable buttons. These buttons could be programmed to make a model walk or a transmission gear shift pattern and alot more with just one press of a button.

I've been thinking about using the 555 timer on the controller end to produce a pwm signal for the servo driver. However, I do like the thought of using a microcontroller. Does the microcontroller need to have a spring in the controller for the return to center steering work on the servo. With the Lego speed controller it uses a red button to center the servo motor. Which allows the servo to hold any of the possible positions with no input on the controller end but when you try to power your wheels with a drive motor that is connected up to the same receiver that is holding the position of the servo motor at the same time the servo motor instantly returns it shaft to center.

Yes! Check this out. It all start with an idea a LEGO IDEA. What you see down below is the 5206 speed computer and two servo motors one of them is dismantle to have a better view of the main subject. What If the speed computer was made out to be a servo driver. This can connect up with any motor up and establish a basic servo function control over a motor.

9 volts is the most I put on the servo. I been thinking about the servo motor, and wanted to share my re approach on a servo design. The route I'm taking is back to the basics and divide the servo motor up back in to its basic parts. The servo is basically made up of gears motors and electronics. Lego has 2/3 of this already made, all they need is the right electronics to be flexible enough to accommodate a fluid construction for servo function.

There are sever areas a U-joint can break at. I've seen various approaches on how to strengthen the U joint, tho I never tested any of these method out for myself. My favorite is using heat shrink tubing.

What I did here is I bypass the IR transmitter and take that data output from the IR controller and send it to the data input on a RF transmitter. Then the RF receiver picks up this signal and send that data to the output pin on the "IR receiver".

I had a car that used break drums for the back wheels and when a bunch of break dust would gather inside them they would slip every time I touched the break.

Thanks clearing that up for me. Sounds awesome what your doing. I'm looking forward to see this. I've been in the process of making improvements to my H-bridge and been looking at the other methods on how to control one. The recent method I've been successful testing is controlling the H-bridge with just one signal wire output on the Lego receiver.

Amazing! That is a clever design.

That is definitely possible NORAN. But I want to say that the Hydraulic system can be divided into two categories, open-center system or a closed-center system. It is critical to incorporate both style of systems and not just employ the methodology of one.

Amazing Work! You Make it look so easy.

I think this has something to do with the magnet in the motor.

Thanks! I'm trying to move away from using the voltage divider to power the receiver and seek better alternatives. I've been thinking lately that it is probably better to build my own speed control unit and control the H-bridge with the Ir receiver not begin in the circuit at all. Thanks that is Interesting! Is the output voltage really 1.2v to 1.8v, surely that must be a typo as it can handle up to 36v. Not exactly, both resistor are in series with the battery. The current flow is 0.0136ma around at a idealistic 15v and from that I was able to calculated out power consumption on the resistors and it appears that they are consuming around a 1/5 watt of power which is not bad consider they are rated for 1/2 watt. Now my battery voltage is not a exact 15V usually it tops off around at 13.6 volts with the AA rechargeable batteries.

@BrainZ: Amazing! You did an excellent job on building this circuit. Thank you for putting up instruction on how to build it. Definitely looks compact enough to work on most models. Keep up the excellent work! What gets me is How Fast the Servo can turn, That is a major step up from what the PF speed remote is able to do. It is a shame tho, that is why I use the toggle switch remote for steering. I want to include that It is possible that a full proportional servo steering is on the TLG's future list and a dedicated steering remote as well. That is why I building my RC circuit to be very compatible with the future PF devices like a full proportional servo and remote that could potentially be down the road.

I appreciate your response Philo. I'm glad that your interested. Sorry for taking so long to reply, I've been busy lately. I linked the top pics to the folders and the pics inside the text to the full size images. The main part of what I posted is still on the drawing board, Though I did forgot to mention at the end of the post that one of the biggest disadvantages as to having a separate power supply for the RF receiver and motors is that if the RF receiver power is turned off what is going to cut off the battery power to the motor when their in motion. I've been thinking about how to solve this problem the most efficient and quickest way I can.

Hi, I'm going to be posting all my current electrical modifications for the PF system here and present everything like a guide manual and provide schematic, data sheets, and a parts list. I've been doing a lot of research on electronics lately and been making great progress on it all and decide to start posting what is going on here along with my successes and failures at developing this. I've been contemplatingseveral ideas as how to build this and will be going to demonstrate how to do several things such as convert the IR communication link to 433MHz RF and transmit a possible total of 4 channels out of one antenna and much more. This topic is not only about building off the existing Lego PF electric system, It will contain a basic understanding about the electrical components and look at all the different ideas that can be implemented as to how everything all works together from everything between the batteries to the motors to the controls. One of my main goals here is to up the scale at which models can be built and powered effectively by one or two motors. One of my longest going disputes is determining a proper battery pack to power my motors. From the very beginning my original idea was to have a 18v battery pack powering a 18v motor. However, awhile back I showed how to upgrade the XL motor with a motor that functions on voltages ranging from 8v up to 16v, so now I'm deciding between either using 12v or 15v battery pack to power the motor. Choosing a battery can be expensive and understanding the battery's voltage range is very critical for the circuit to work properly. There is a bunch of choices here as to what the battery powering the motors should be. I've been thinking on either using a Li-po battery or Li-ion or just continuing on using AA batteries. The next part of the circuit that is between the motor and the battery is the H bridge motor driver. This is the most critical aspect of the circuit as towards allowing the battery current to the motor and that current is dependent on several factors such as input voltage and temperature. There are several types of transistor out there and it is recommended to have a proper transistor in respect to the device you want to power. By looking at the data sheet it shows that the motor at maximum efficiency current 0.71a and the stall current 5.56a at 12v so here it can be establish that the transistor should be able to handle 10a if two of these motors were to stall simultaneously. The transistor I am using here are know as MOSFETs and the part number on the transistor is IRF540 and the the other one is IRF9540. That is my first H bridge I put together and there is definitely a range of improvements that can be done here. Now in order to power the H bridge to dive the motor is done by the 9v IR receiver motor connection. There are several ways I've gone about powering the 9v PF receiver from a higher voltage source such as 15v. In the picture below I use a voltage divider which is able to drop the voltage down to a usable voltage supply for the 9v receiver and the amount of current is drastically reduced to the 9v receiver, you will not be able to drive a micro motor with it but you will be able to power the H bridge, One of the main advantage here is using the high 9 volt supply out of the 9v receiver because the transistor is primarily a voltage driven device and that means more current for the motor. The main part of the upgrade is converting the IR signal to a RF signal. The remote control part of the modification is very easy and does not require much to do, I am almost done with this part. In the pictures below shows the only modification I made so far for the antenna. The benefits here is have a strong base for the antenna to collapse on. It was tricky process to get the antenna screw in that 3mm hole I made, I had to take out the battery metal connection tab on the controller and pass the screw through the battery holder opening in order to insert the screw in there. Now for the main part in converting the IR signal to a RF signal on the receiver end. While the RF transmitter can handle voltages up to 12v the RF receiver must require a smooth constant voltage around at 3v which can be tricky to do if your using a total supply voltage around 15v, 12v, or even 9v. Instead of using a voltage divider to drop the voltage down to 3v for the RF receiver, I'm going to use a voltage regulator and the reason behind this is the battery voltage will drop when the motors begin to rotate and that will cause a drop in battery supply voltage and the voltage divider will fluctuate in response of this. A voltage regulator will hold a steady supply voltage to the receiver so no matter what the demand voltage is on the battery you wont lose connection with the RF receiver. However, one of the big disadvantages about the voltage regulators is that it converts a lot that energy to heat especially when it is working off a large voltage supply like a 15v battery. So the next option is to isolate the RF receiver voltage supply from the motors voltage supply and there are numerous benefits behind this, the most notable on the list is no modification has to be done to the Lego IR receiver so any version of the IR receive will work with this RF receiver unit. To accomplish this I will work off the infrared communication and connect with the PF IR receiver by a IR emitter that is apart of the RF receiver unit and separate the RF receiver voltage supply that way. Another advantage behind this is more current for the motor. Also the circuit could be replaced with a fiber-optic communication link for the same results. By using the IR link to transmit data signal from the RF receiver to the IR receiver you could theoretically control multiple IR receiver units with just one infrared signal. Now the RF receiver will be able to output 4 data signals and each data signal can be assigned each there own channel. Not only will the RF transmitter and receiver will be able to communicate a potential of 4 data signals out one antenna, it will also have the ability to code the RF signal 256 ways. I will post more when I finish testing everything.

Nice work Doc. It has that Star Wars giant battle ship look to it. I spy something blue .

Looks great. Steering looks very strong. I like the fact that both front and back steering are independently controlled.

That battery can easily be switch with a DC adapter tho. Also focus your attention on the battery pack and cable in the picture. If this thing had any force flying up at lest there would been some instability with these parts. You just don't get a clear picture like that when stuff is in motion.

It sit too flat in the air and some how made a perfect horizontal 90 degree rotation between pictures. Also I can see the digital pixel alteration with my computers magnifying glass.

Question: Did you have the differential axle go straight to the tire?

Nice work. Pneumatic doors are awesome! Music is great too.

One of the biggest problem around using metal to shim against the differential, Is that metal can bend and any deformation in the shim can create some resistance on the differential. It has recently come to my knowledge that the differential in this picture was paired up with a deformed metal shim and the resistance between them allowed the shim to be able to cut in the differential like that instead of the shim freely rotating with the differential. The other metal shim I am using is a great fit with the differential. When there is shim resistance on the differential you can spin one tire by hand and the other adjacent tire will rotate and in the event when you have no resistance on the differential with the shim you will be able to spin one tire by hand and the differential will rotate. All that must be done without the motor connected to the drive axle.