RC Deck - Performance Power Supply With Radio Control

[NoEXIST]

Project is in progress, first real built prototype coming soon. (Not final look, not every way to connect it to your build is included in these renders)

The main idea is to use RC transmitter with Lego. This is the best way to control your model. Especially fast models.

RC Deck will have several ways to use:

1. As a brick - Top part will slide and connect to the battery box with two 14500 elements - 2s 7,4v 1000mAh (Vapcell H10)

This allows you to use familiar form factor of battery. Size is 8x4x4 studs (one plate higher comparing to the buwizz 2.0 brick)

Up to 2 Buggy motors can be used, your electronics are completely safe with 7,4v

The best thing about using it this way, you can easily put there another 14500 battery if first two are discharged right now

2. As a transmitter - You can connect to the deck whatever lipo battery you have (limited by Lego motors possibilities)

Allows you to use up to 4 buggy motors - stacking more than 2 motors on one port isn't recommended as Lego connectors can melt (that's why there's 2 ports for driving channel)

Allows you to use small size of Deck itself and move battery away

Parameters:

Ports/Channels: - 2PF ports to use more powerful motors for propulsion

     - 2 Control+ channels - 1. Steering (there will be opportunity to use RC servos or GeekServo with this channel)

    - 2. Additional function

Electronics:

RC Deck: - Receiver - Dumborc x4fm

- 30A brushed ESC for PF channel 

- 2 5A brushed ESC's for Control+ channels

Additional battery box: - Vapcell H10

 

Details: 

- sliding RC Deck on the battery at the same time connects it

- complex PF ports for polarity reversal without weak points as switches are

 

Hope you like the concept! Feel free to leave your opinion or your ideas to improve this thing.

P.S. Hope this topic is okay for this part of forum

[Ryokeen]

Interesting concept so far, i'm just not sure if it's worth to have the battery tray for the 2 14500. As you stated the top part, where the connections are, will slide to give access and the bottom part is the one that has the stud holes. That might make buildings using this a bit complicated as the bottom part is fixed into whatever thing was build and the top part needs to have enough space to slide off and be moved enough so one can acutally access the batteries.

Will be interesting to see how you will manage to make a geekservo(or any rc servo) use the same port/s as a control+ motor. From what i know control+ "simulates" a servo with their build in encoder and need hard build limits. I'm not sure if that part of the software is in the motor or the control+ hub/app.
An rc servo on the other hand just uses a pwm signal mostly between 1000µs and 2000µs with 1500µs makring the center position(yeah i know some servos have a bigger range, such as the geekservo 360). Or more most RC transmitters/receivers only use that spectrum, nothing more. All the logic on how far the servo need to rotate to reach a desired position is in the servo itself.

[NoEXIST]

4 hours ago, Ryokeen said:

As you stated the top part, where the connections are, will slide to give access and the bottom part is the one that has the stud holes. That might make buildings using this a bit complicated as the bottom part is fixed into whatever thing was build and the top part needs to have enough space to slide off and be moved enough so one can acutally access the batteries.

 

There will be some more connection points, especially on the top(as it can be used  without this battery too). 

 

4 hours ago, Ryokeen said:

Will be interesting to see how you will manage to make a geekservo(or any rc servo) use the same port/s as a control+ motor. 

It will have separate 3pin port, but will be connected to the same channel. I'll double that one socket on receiver and first will go directly to the body, and second one through Arduino to the control+ motors. At least I hope this will work:) 

[Lixander]

That is a real breakthrough! One the first of these, if not the first actually, of such RC to Lego ”hubs” projects that will be easily available in Europe (I hope). Good luck!

Also, I didnt understand exactly if it can use also a 2S Li-Po (max of 8.40V). If yes, then how is the connection of the RC Deck - battery made and is there any battery size limit (mAh or cm)?

Edited January 12 by Lixander

[NoEXIST]

22 minutes ago, Lixander said:

Also, I didnt understand exactly if it can use also a 2S Li-Po (max of 8.40V). If yes, then how is the connection of the RC Deck - battery made and is there any battery size limit (mAh or cm)?

2s and 3s lipo's can be used. I choose 14500 batteries for the box because they less likely will be discounted than a noname lipo battery that matches size of a box.

It uses jst connection. As a product it can be a full brick with battery and also just a "receiver" without a box with 14500 batteries, so you can put your lipo everywhere in your MOC and it can as big as you want

[Lixander]

53 minutes ago, NoEXIST said:

2s and 3s lipo's can be used. I choose 14500 batteries for the box because they less likely will be discounted than a noname lipo battery that matches size of a box.

It uses jst connection. As a product it can be a full brick with battery and also just a "receiver" without a box with 14500 batteries, so you can put your lipo everywhere in your MOC and it can as big as you want

Ok. Thanks for the answers!

[aFrInaTi0n]

Interested as hell and already waiting for yeaars for someone doing such!

I am at work currently and can't read through, but seems like it shall form one unit housing the receiver and the batteries - personal wish for those optionally being able to be used as two separate units it would be from me.

Wishing all the best for this project getting a success!

[NoEXIST]

6 minutes ago, aFrInaTi0n said:

I am at work currently and can't read through, but seems like it shall form one unit housing the receiver and the batteries - personal wish for those optionally being able to be used as two separate units it would be from me.

That's exactly what the purpose is:)

[amorti]

I am very into this.

Like @aFrInaTi0n I am obsessed with making fast motorcycles and cars from Lego.

So far buwizz3 is the only way to power two Buggy motors without home gaming RC gear. But then it is limited by Bluetooth range and lag. Not to mention long charging times and a 200€ bill if you want to be able to swap the cells.

If you can make this, it would make buwizz3 obsolete for me.

Edited January 12 by amorti

[Alex Ilea]

This looks interesting and I can see the use for such control unit with a Radio Control. I do however  have to say that the ports seem to be in a very bad place. Why not add 2 more PF ports or 2 more PU ports? Look at Buwizz 3.0, the design of the ports is quite good, but not perfect. In the BW case, after you fill all the PU ports and you want to add the PF connectors, the PF cables will be bent in a less than ideal way, and this is something you should try to improve on.

[amorti]

2 hours ago, Alex Ilea said:

This looks interesting and I can see the use for such control unit with a Radio Control. I do however  have to say that the ports seem to be in a very bad place. Why not add 2 more PF ports or 2 more PU ports? Look at Buwizz 3.0, the design of the ports is quite good, but not perfect. In the BW case, after you fill all the PU ports and you want to add the PF connectors, the PF cables will be bent in a less than ideal way, and this is something you should try to improve on.

I don't think this unit is really intended for cranes and forklifts etc. which can use 6 ports like a bw3 has, but don't require high output.

It's intended for fast models requiring one servo for steering, one servo for 'something else', and up to 4 drive motors plugged into the two pf ports.

For me at least, fewer ports and less complications is all for the good.

[Alex Ilea]

51 minutes ago, amorti said:

It's intended for fast models requiring one servo for steering, one servo for 'something else', and up to 4 drive motors plugged into the two pf ports.

I understand that, but why not make it comparable to the competition? Why be different for no real advantage? Yes Radio is a huge upgrade, but port limitation would detract some portential buyers.

This product would be a direct competitor to Buwizz 3.0, so you would need to make it appealing to more people than just to a small category.

And regarding the ports, imagine you build a Lego version of the Traxxas Bronco: you need drive, steering, 1 port for gearbox, 1 port for front diff, 1 port for rear diff. 

[kbalage]

Interesting idea! I have a 2.4RC Brick that had a similar concept with 2 PF ports, although that required an external Flysky receiver. Having more than 2 ports is great, but I wonder how you plan to deal with PU servo control if there is no software involved for the calibration.

[NoEXIST]

4 hours ago, Alex Ilea said:

This looks interesting and I can see the use for such control unit with a Radio Control. I do however  have to say that the ports seem to be in a very bad place. Why not add 2 more PF ports or 2 more PU ports? Look at Buwizz 3.0, the design of the ports is quite good, but not perfect. In the BW case, after you fill all the PU ports and you want to add the PF connectors, the PF cables will be bent in a less than ideal way, and this is something you should try to improve on.

I was thinking about more ports, but this can't be done as it was in buwizz. The problem is how much current can provide buwizz for each port, in reviews if I remember correctly, were told about 6A (in peak?). So if you are using powerful rc esc's there's simply no space for 6 of them. Even if I remove sliding feature.

Port configuration of course can be changed, but there will remain 3 channels 

[Aurorasaurus]

I'm not sure if this has already been mentioned, but why 2 PF connector points and only 2 studs? That would mean you could only use 2 motors, right? I would think you would need 2 studs per PF connector...

[NoEXIST]

1 hour ago, Alex Ilea said:

I understand that, but why not make it comparable to the competition? Why be different for no real advantage? Yes Radio is a huge upgrade, but port limitation would detract some portential buyers.

This product would be a direct competitor to Buwizz 3.0, so you would need to make it appealing to more people than just to a small category.

And regarding the ports, imagine you build a Lego version of the Traxxas Bronco: you need drive, steering, 1 port for gearbox, 1 port for front diff, 1 port for rear diff. 

It is a great competitor, but for me it's real purpose is different to purposes from buwizz ads.

I think the advantage of using only one rc deck instead of few few buwizz units is significant, but you are definitely true, this product is for small category of people.

Using 2 PU ports is already a compromise to make it useful for more people, but it's definitely a complication. If I can’t cope with controlling of PU motors in servo mode, it seems to me that it won’t be a big loss to switch to PF connectors for all channels, since lately I’ve seen more and more people using alternative servos such as Cada. Also, using a geekservo has a lot of advantages compared to any version of Lego servos.

Creations as remake of Traxxas bronco aren't really a creations that are designed for driving performance. Again, more like complex cranes, in my opinion.

[gyenesvi]

This is an interesting idea and a long awaited product. Great that you tackle the problem and getting close to a prototype!

Actually, I have been thinking a lot myself how such a hub would be possible, what electronics it would require and what outputs it could have. I believe there are a few tricky points, such as

- The receiver. Everyone would like to use different transmitters, which come with their own receivers, and they are not compatible. So you either have to make the receiver external and swappable, or you commit to one brand, and then everyone will have to buy a compatible transmitter for that. In that case DumboRC is a cheap and seemingly good quality choice, though I have just bought a FlySky transmitter.. So I guess it won't be possible to swap in my receiver? Or is that doable?

- The ESC: as you say, you need to add ESCs for each drive output port, and even two ESCs can get big enough. Are you using a dual output ESC? Are the two PF output channels independent? If yes, how do you control them separately? Many transmitters only have one trigger.. so is one of the ports for steering, using a PF servo? Or are the two outputs controlled simultaneously, for drive?

- The servos: when thinking about this, my conclusion was that the focus should be on GeekServos, because they are much more precise and smaller than lego servos, and the PF servos are even hard to buy (and 3rd party servos are not proportional), plus they don't require any special electronics or software, they can run off the receiver. So I don't quite get why you want to complicate things with PU ports. Those require some FW to drive them, right? So you need to add an Arduino for that kind of control?

- The connectors: what kind of connectors to use to avoid melting (as they can become the weak spot). I'm not quite sure how it could handle 4 buggy motors. For that, you'd have to stack two of them on one port. But as far as I know, just stacking two of them on one port can already make the PF connectors melt. I thought this can only be avoided by using one buggy motor per port or using different connectors. Have you made tests in this regard?

Are you planning to make your own PCB that will have all the electronics components on one chip or will the components be separate, and hence maybe swappable? I think separating the electronics from the battery is a nice idea. I'm not sure about the 2s (7,4V) battery though, one advantage of a proper RC system could be the use of 11V battery (or faster brushless motors that are strong enough with 2s LiPos, but that's not the case here).

Edited January 12 by gyenesvi

[NoEXIST]

1 hour ago, Aurorasaurus said:

I'm not sure if this has already been mentioned, but why 2 PF connector points and only 2 studs? That would mean you could only use 2 motors, right? I would think you would need 2 studs per PF connector...

In my opinion this is the easiest way to reverse the motors. Imagine building a chassis that uses 4L motors, they are geared to one axle, but two of them are spinning in a wrong direction. That a situation you will need to rotate your connector.

 

[FriedlS]

Wow, sounds great! I saw a few years ago the rc brick version on yt which @kbalagementioned. 
I also hope this projects is available soon😊

[Lixander]

1 hour ago, gyenesvi said:

This is an interesting idea and a long awaited product. Great that you tackle the problem and getting close to a prototype!

Actually, I have been thinking a lot myself how such a hub would be possible, what electronics it would require and what outputs it could have. I believe there are a few tricky points, such as

- The receiver. Everyone would like to use different transmitters, which come with their own receivers, and they are not compatible. So you either have to make the receiver external and swappable, or you commit to one brand, and then everyone will have to buy a compatible transmitter for that. In that case DumboRC is a cheap and seemingly good quality choice, though I have just bought a FlySky transmitter.. So I guess it won't be possible to swap in my receiver? Or is that doable?

- The ESC: as you say, you need to add ESCs for each drive output port, and even two ESCs can get big enough. Are you using a dual output ESC? Are the two PF output channels independent? If yes, how do you control them separately? Many transmitters only have one trigger.. so is one of the ports for steering, using a PF servo? Or are the two outputs controlled simultaneously, for drive?

- The servos: when thinking about this, my conclusion was that the focus should be on GeekServos, because they are much more precise and smaller than lego servos, and the PF servos are even hard to buy (and 3rd party servos are not proportional), plus they don't require any special electronics or software, they can run off the receiver. So I don't quite get why you want to complicate things with PU ports. Those require some FW to drive them, right? So you need to add an Arduino for that kind of control?

- The connectors: what kind of connectors to use to avoid melting (as they can become the weak spot). I'm not quite sure how it could handle 4 buggy motors. For that, you'd have to stack two of them on one port. But as far as I know, just stacking two of them on one port can already make the PF connectors melt. I thought this can only be avoided by using one buggy motor per port or using different connectors. Have you made tests in this regard?

Are you planning to make your own PCB that will have all the electronics components on one chip or will the components be separate, and hence maybe swappable? I think separating the electronics from the battery is a nice idea. I'm not sure about the 2s (7,4V) battery though, one advantage of a proper RC system could be the use of 11V battery (or faster brushless motors that are strong enough with 2s LiPos, but that's not the case here).

Now, that you spoke about the voltage,  I remembered.........the buggy motors won't handle a 2S LiPo because of the heat. Also, a charged 2S LiPo has 8.4V.

I burned 3x buggy motors until I finally understood that a RC system would simply burn these motors.

Probably, a RC compatible system thought for using with Lego electronics won't do that, because, most likely, the discharge rate is the problem (the ESC might give too much current to the motors).

Edited January 12 by Lixander

[amorti]

I'm with @gyenesvi on the geek servos. Lego PF servos are silly money and don't last long at all. Third party PF servos can't do proportional steering.

PU servos would need firmware, and even once you get them centred and the limits set up, they have quite a lot of slack.

So, that leaves geek servos. I don't have one and never used one, but seems like an all round better option: smaller, stronger, more accurate, (assuming it's the same as any RC servo) less slack, easier to program in this context.

Would it be possible to give two twinned PF outputs on the top? Sharing a speed controller, but not requiring plug stacking?

Edited January 12 by amorti

[NoEXIST]

@gyenesvi

RECEIVER: Actually as I'm not going to produce them as much as buwizz do, there will be an option to try whatever receiver customer wants, but it might be as small as this one is:

I actually have seen similar receiver from FlySky, I think it can be possible with it.

I also did a bit calculations, the price won't be too high compared to competitors even if the transmitter is included in the kit.

 

ESC: Two outputs are controlled simultaneously for porpulsion, one 30A ESC for both PF ports.

 

SERVO: You're right that it is a comlication and I'm not sure there is a space for extended FW for them(waiting for components to make first working prototype). There is a way that maybe is even better than PU servos - Focus on GeekServo and making two "dumb" ports for other functions(gearboxes, diff locks, LED's, etc.). They can be PU ports and PF aswell. In this case it can have even 4 channels which might be useful.

 

CONNECTORS: I come with the experience of my friends who did these or similar things for themselves. 2 Buggy motors is a crucial moment when it can melt. There's two way out of it: 

Nylon connectors for the motors which is not at all practical in terms of sales.

Y-wire - one port to 2 motors

 

BOARDS: This time I'm definitely go for separate electronics, so it's easy to exchange one of the components.

 

BATTERY BOX: I'm making focus on a Deck itself and battery box can be a nice addition for the ones who want. There is a lot of pros to separate battery and "receiver"

22 minutes ago, amorti said:

Would it be possible to give two twinned PF outputs on the top? Sharing a speed controller, but not requiring plug stacking?

Didn't quite understand the question, but there's no problem to put 2 motors on separate ports instead of stacking 

[amorti]

17 minutes ago, NoEXIST said:

@gyenesvi

Didn't quite understand the question, but there's no problem to put 2 motors on separate ports instead of stacking 

Could you have 4 sockets, even if there are only two ESCs? So that two would only be repeaters. In this way, you wouldn't have to stack the PF plugs.

I imagine it like using the old electric plates to power two 9v motors.

[NoEXIST]

3 minutes ago, amorti said:

Could you have 4 sockets, even if there are only two ESCs? So that two would only be repeaters. In this way, you wouldn't have to stack the PF plugs.

I imagine it like using the old electric plates to power two 9v motors.

A bit crazy idea, but definitely useful, I'm not sure there is enough area on top to squeeze it all.

Maybe a good idea for other versions? Like making it (top part) 8x5x2

[Ryokeen]

@NoEXIST as a side node, the two 14500 cells will, as other ppl said, give around 8.4v fully charged, that's fine for motors as i think those are rated for 9v. But a lot of 14500 cells are rated only for 10A drain, that could be a problem if you use at leat 2 30A esc. Yes they will only suck as much as the motors need, but alone the possibility that an esc can request more Amps than a battery can provide is not good. That's why most of the time you see high C-Rating LiPos in rc projects. For 2x30A esc you would preferr a lipo with lets say 2000mAh and a 30C-35C rating.

But regarding what you want to squeze in and considering the marked you probably want to target, i wouldn't mind if your project was just some sort of adapter from RC to lego. Means have connections for a LiPo(deans or xt60) and input ports for signal cables from a receiver.
So your product would serve as an interface between a LiPo and an rc receiver, offering PF/PU and 3-Pin servo connections. That way ppl could also use receivers they already have, switch the channel layout and you save on hardware.
One would just connect the motors/servos to your thing, then connect a LiPo and a receiver. Sure not an all in one package, but that way the receiver could also be somewhere else utilizing space.

Also regarding GeekServo only, even common RC servos fit quite well into the lego stud space. And honestly if a geekservo won't cut it cause it's to week, you have to go for a bigger servo ;)