Some ZZMT questions

georgefe · Post by **georgefe** » Wed Mar 22, 2006 2:35 pm

Ok, So I am looking to add my own board to the ZZMT to control it instead of the board that comes with it. I have a few questions. I did read through the forum and tried searching but some of the results were either really old or not so clear.

- Can the electronics on the MT handle 4 cells in series? (4.8v) Can the motors and the driver board handle it? Will it still receive controller signals normally or will it mess that up

- Is their a good tutorial to insert a micro RC servo into the MT? I have seen some pictures that implied they did it but I didnt know about the gearing and actual working of it. I am not conserned about how I am going to control the servo, just getting it in their and having it work mechanically.

- Can the ZZSE steering servo be fit into the MT?

Thanks!

crazydave · Post by **crazydave** » Wed Mar 22, 2006 3:45 pm

Yes the stock board will handle 4.8v no problem.

The MT is not proportional, so a servo of any sort would be of no use to you with the stock board.

What you're seeing is people who have put Iwaver PCBs the the MT to get full proportionality, in that case you will have to build a servo in order to get the proportional steering. I believe the SE servo is what people are basing their concoctions off of.

I don't think more that one or two people have even done this, and you apparently have seen that, so you know as much as the rest of us really.

LBRC was probably the first. Betty.k stuck an Iwaver board in his, but did something with a resistor to get 2 steps of steering without using a servo. I can't think of anyone else off hand that has built a fully proportional MT.

45tr0 · Post by **45tr0** » Wed Mar 22, 2006 9:01 pm

crazydave wrote:. I can't think of anyone else off hand that has built a fully proportional MT.

i think clint did one? if memory serves it had an un-cased micro servo installed up front? mind you i mighta been

that day...

georgefe · Post by **georgefe** » Thu Mar 23, 2006 12:53 am

Thanks for the quick replies!

I guess I will just stick with an upgraded motor on the steering and see what happens. I will post pics as soon as I get my boards together!

crazydave · Post by **crazydave** » Thu Mar 23, 2006 6:43 am

45tr0 wrote:
crazydave wrote:. I can't think of anyone else off hand that has built a fully proportional MT.
i think clint did one? if memory serves it had an un-cased micro servo installed up front? mind you i mighta been that day...

Yeah, I believe you're right, sorry I forgot ya Clint.

georgefe · Post by **georgefe** » Sun Mar 26, 2006 11:52 pm

Ok, I started my modding off by taking on the controller. I first ripped the controller apart and off loaded the switch and the LED.

Then I soldered on wires to the pads of the controller so that I could control the movements via a computer.

Here is the finished product. I added a DC jack so I didn't have to eat up so many batteries and I mounted to car charger and antenna in their as well.

Charging.

Side View.

Clint · Post by **Clint** » Mon Mar 27, 2006 5:16 am

crazydave wrote:
45tr0 wrote:
crazydave wrote:. I can't think of anyone else off hand that has built a fully proportional MT.
i think clint did one? if memory serves it had an un-cased micro servo installed up front? mind you i mighta been that day...
Yeah, I believe you're right, sorry I forgot ya Clint.

yuppers. gws rx, jr55 servo, novak spy, lipo. All fit fine in an articulated zzmt. kind of expensive if you dont already have the parts, so i wouldnt
really suggest doing it this way.

LBRC · Post by **LBRC** » Mon Mar 27, 2006 5:29 am

Computer control could be interesting, epically with preprogrammed movements, or are you thinking about a camera?

georgefe · Post by **georgefe** » Mon Mar 27, 2006 7:49 pm

Naw, I'm not going to put a camera on there. The computer control part is just for fun. But the part that I am really modding it for is so that I can replace its electronics with a PIC board and control the motor speed myself and possibly add a servo for the steering.

Clint, yours is awesome, I was thinking of picking up a hitachi HS-55 sub micro servo for the job.

LBRC · Post by **LBRC** » Tue Mar 28, 2006 12:15 am

I wouldn’t recommend the HS55 for the job, from experience it’s a bit large, also puts the feed horn too far to one side. My favorite is the Interflite Mega Micro but I also replace their motors.

I started a photo tutorial awhile backin my ZZ gallerybut still haven’t finished, got distracted, if you select a thumbnail you can not only see the full size photo but also scroll down for detailed instructions/comments under most of them.

Blue Bird BMS-303 - Size: 19 x 15.5 x 7.5 mm, Torque: 11 oz.in at 4.8 volts, Speed: 60° in 0.11 sec., Pot: 5K surface mount. Expensive, but the smallest and with a coreless motor it’s also the strongest and fastest in its class. Unfortunately the surface mounted potentiometer makes it a real bugger to modify for use with an Iwaver or Mini-Z circuit board.

Interflite Mega Micro MMIC43 - Stock: 19.6 x 19.6 x 8 mm, Torque: 5.5 oz.in at 4.8 volts, Speed: 60° in 0.12 sec., Pot: 10K ohm. Best fit for a ZZMT primarily doe to feed horn position but also width, it does however need a 10K ohm resistor to match an IW or Kyosho circuit board, and a ZZ 22K (red) motor for more torque.

GWS PICO+F/BB - Stock: 22.8 x 19.8 x 9.5, Torque: 11 oz.in at 4.8 volts, Speed: 60° in 0.12 sec., Pot: 5K ohm, Very strong and smooth however it ends up being awkward to install in because the feed horn sits all the way to one side while the larger motor ends up being very long on the opposite side. The straight PICO although smaller has the same problem.

HiTec HS-55 - Stock: 22.8 x 24 x 11.6, Torque: 15.27 oz.in at 4.8 volts, Speed: 60° in 0.17 sec., Pot: 5K ohm. Strong but slow and too fat for most micro work. For larger cars though this servo has real modification potential it’s torque comes from gearing so adding a high speed Bit or ZZ motor can have dramatic results.

Clint · Post by **Clint** » Tue Mar 28, 2006 2:47 am

woops I made a typo in my prev post.

this is the servo i used.

JR Sport SM15
Type: Sub-Micro
Torque: 15 oz/in @ 4.8V 18oz/in @ 6.0V
Speed: .21/60 @ 4.8V or .17/60 @ 6V
Dimensions: 0.45"(11mm) x 0.87"(22mm) x 0.85"(21mm)
Weight: 9.0 g (0.32 oz)

it's a snug fit between the two shock towers, but dimensionally it works.

codesuidae · Post by **codesuidae** » Thu Mar 30, 2006 6:42 pm

georgefe wrote: Then I soldered on wires to the pads of the controller so that I could control the movements via a computer.

What IO on the computer are you using? Parallel?

georgefe · Post by **georgefe** » Fri Mar 31, 2006 9:22 am

Well, I am going to use an EB55 evaluation board, which is pretty much an ARM7 core with a bunch of peripherals on it. Basically a microprocessor similiar to a PIC or BASIC STAMP sort of thing. I am going to take these three wires from each of the pads and connect them to a digitally controlled SPDT (single pole, double throw). Then when I send a certain signal from the ARM board to the switch, it will be the same as hitting the button on the controller. I was just simplifying it when I said "computer" control. I can talk to the EB55 via the computer so I can also then control it via a computer.

georgefe · Post by **georgefe** » Wed Apr 12, 2006 1:40 am

I'm sure you were all wondering why I went through the trouble of making the charging box. Well I have accomplished one of my goals and the Mini-RC car is now COMPUTER CONTROLLABLE!!

This is the interface between the lines I ran off of the controller box (the black thing) and the computer (the EB55).

I first just made certain push buttons on the board make the car go forward, back, left and right. Once I got that working, I just made it do a little dance in a loop. Here is the setup:

A Video of it doing its little jig is here:
http://eichingers.com/arstechnica/MVI_2428.AVI

ynad · Post by **ynad** » Wed Apr 12, 2006 12:24 pm

i like it