ZZSE many modding questions
 

I have been looking at these boards for months, but am a new member. I have alot of new ?'s and old ones I can't find answers to.
-Where can i find a schematic or diagram for ZZSE car?
-Under the black clip that holds in the PCB is what looks like a frequency crstyal. Is it actually that? (i want to change it to work with a standard set)
-Has anybody tried to mod through the LED connector on the top of the PCB?(i think there is some potential there)
-What is the fastest/most impressive mod out there?

Re: ZZSE many modding questions
 

Welcome :)

I am not aware of a complete schematic, but I've done the h-bridges, mostly for the purposes of documenting the mosfet mod.

You can find the schematic in this thread

Yup, thats a 4.000Mhz crystal. Without a schematic I couldn't tell you what exactly its connected to, but I suspect its for whatever ICs the SE uses, one of which decodes the serial data from the RF stage, and one that I haven't done anything with that I guess has something to do with the RF receiver.

To accomplish what?

I'd say the mosfet mod including jumpering the n-channel gates to the p-channel gates (which we generally attribute to cyborgZero).

Note that even with the mosfet mod the ZZSE still only runs the motor at a maxium 30% duty cycle (for year '03 cars, I haven't checked the new ones), so when I finish my CPU replacement it will be, IMHO, the most impressive :)

My thought for the LED connector is that you could run the motor through two relays and some diodes from there. It just wouldn't be propo. It could be removed easily and wouldn't interfere with the existing motor clips. I don't see any other uses but to create plug-and-play solderless mod.

You could use the connector to run a motor, but it seems that it would simply run in forward or reverse with the car. Forgive my lack of imagination, but I can't think of anything particularly useful to run with such a motor :)

i have been having a problem with the back of the car moving up and down as it goes forward. It seem that the wheels are misshapen, but i cant tell. I took off the tires and caps, now runing on just the rims, it does the same thing. I've used many different axles and still the same. Is this a common problem and is there a fix?

It will hop from some small flat spots where they cut the wheels off the sprues. With the tires make sure they are on perfectly flat and straight!

I've gotten some (bit clones) where the rear end did the same thing, but in my case it was the rims not being perpendicular to the axle-shaft.

I don't know about the power take-off plug, but I'm sure there's something really cool that could be done with it.

I was thinking that if you take a similar female plug, and some Transistors, you could add on some "booster batteries" to just power the motor. But I haven't taken a meter to it to see if you still have propo current.

I did notice something odd about the plug used for the lights. My FC3S body has the headlights on all the time, but my AE85 and AE86 bodies only have them come on while running.

I just bought some relays and have some cells coming in the mail. I hope the relays are the right ones I need. I also have an oversized motor that is small enough to fit under the body, but not in the standard clip. It will take some work. I tried the same motor, boched into a cheaper car, and it went slightly faster. The test car is a single cell, so with more current and correct gearing it will fly. We'll see how it works in a zip zap.

I just tested the output on that connector and it doesn't seem to be propo. My meter read about 2.5V no matter what possition the throttle was on, besides the nuetral possition. I couldn't read the amperage , because it was to high for my crappy meter. There was no motor in the car at the time of the test.

The only thing I've done with the LEDs is move the rear lights to the bottom of the car in attempt to get some underglow action.

I had the thing mostly together, it was beautiful, but I have a small problem. The oversized motor turns the wheels nicely with penty of torque (hard-wired to 2.4V). The problem it that the relay used to switch the motor is only half triggered. I can hear it click when I move the trigger on the remote. But the normally-open part of the relay doesn't close with the current of the LED connector. I used the relay with the lowest triggering current that I could find at RadioShack. I need one just slightly smaller that what I have.

The relay needs 3.5V at 89.3mA

Im trying a large FET that I have in place of the relay, but I can't get it to work either.

Any ideas? The LED connector puts off 2.4V

IMO your best bet is the mosfet. You could find a lower voltage relay, but the relay coil is going to eat a heck of a lot more power than the motor. Your 90mA coil is taking nearly half what the regular motor would.

I'm still not sure what you are trying to accomplish though. Why not just connect your new motor using the existing motor connections?

Im trying to avoid permanently changing the car and any way by limiting my changes to the LED connector and motor clip/heatsink. Also because nobody has done it exactly this way as far as I can tell. I am trying to use a relay instead of a FET because of the high voltage I plan on using and because I understand their function better.

Do you know where I could find a FET that serves the same function, and how i would use it? I've been trying the FETs with no success.

This is a blurry view of the car in progress. The green things are 2.4V dual cells. Four external cells total. There is still a stock 2.4V battery in the car, so this will be a 6-cell car. I'm not saying that it will be superior to the quad cells, because it does weigh alot. Putting the cells outside the car is the only way I could think of to keep all that weight close to the ground. I'm going to paint them like giant Nos bottles.

PROJECT SUMMARY

-Goals-
create the fastest "1:64" rc car ; )
make it look cool while achieving first goal
keep upgrades modular, and reversible
keep compatible with existing zip zip parts(motors,gears,etc)

-To Do List-
larger controler antenna
increase controller transmitter power
wire batteries
devise an speed conroller(fet/relay)
link internal batteries to existing one without effecting pcb
devise streamlined on-controller charger
fix stearing knuckle
make it look cool

-Done-
mount motor
adjust motor spacing
find correct gear ratio
wire motor
mount batteries

-Tears of Joy-
It purrs like a dentist's drill, with the whole drivetrain(motor, wheels and gears) hooked up to a 6volt lantern battery and under low loads. The final project will be 7.2V. It should have at least the same torque as the un-modded ZZSE, but hella fast. The wheels arn't stopped very easily with fingers.
Going that fast it started to smell like burning plastic, not electronics or motor. I need to start lubing the gears and axle generously. Next time I do this: metal gears, ball bearings. I can't wait to get this thing on the ground and under control and get a m.p.h speed. I'm using blue gears so far. I think the gym floor is the only place i can drive this.
All I need is a relay or large FET that will trigger with the current I mentioned earlier and can handle 7.2V. I think I will mod the relays that I have, tonight, to serve this purpose.
This has got to go at least 12 m.p.h.

(?????) By the way what is the speed to beat? How are you guys measuring it ("quarter-mile", unlimited head start)?

Which mosfets you would use would depend on how much current you expect to run, and if you can handle using surface mount parts.

I'm guessing you will not want to use surface mount parts, mostly because they tend to be difficult to use without making a PCB. You could use something like the IRLR3714, its on resistance is very low and it will handle very high currents. You'd probably want to use a simple switching transistor on the 2.4v input so you can use your higher voltage battery supply on the fet gates. You could do this with your relays too, so you can get enough power to turn them on.

To do it with mosfets you could build a full h-bridge so you can have forward and reverse, which would take 4 mosfets (preferably 2 n-channel and 2 p-channel). If you just want to go forward one will do.

If you are only pushing about 1A for the motor you could use this H-bridge IC.

If you want to stick with the relays you can use a transistor on the 2.4v output from the car to switch the 7v battery to your relay coil to turn it on fully. This is probaby much less trouble than using mosfets since you already have the parts. runtime won't be as good, but I don't think your going to be too concerned about that at this point :)

Thanks that is helpful.

Think im just going to one direction for now. Once I'm happy with that, I will have 2.4 reverse.


(????) When motors fry, do the go to heaven?

I was wondering how motors "go" when the do so at high voltage/rpm. Does the whole motor case get hot then....? Or does the motor fry from the inside out?

The only time I have fried motor so far happened when I was soldering wire leads to it.

I am running this thing at serious rpms and the motor stays "cool". Granted, this is at low loads for long times or accelerating the whole weight (batteries and all) for a foot or so. I have it heat sunk pretty good, but if it goes from the inside out, i can just cross my fingers.

You can power your relay with a circuit like this:

This way the relay coil will be energized using your higher voltage circuit. The 10k resistor can probably be omitted. The transistor is any N-channel small signal transistor, Radio Shack has them.

A motor will use the most power when it is stalled, so they tend to get hot under load. Running unloaded they only get hot if you are exceeding their rated voltage by quite a bit. The armature, the spinning part inside with the wires wound around it, is what gets hot. The current flows through the wires and heats them up.

Failure modes vary, usually it will just get hot enough to melt the wires somewhere (often near connections since they have higher resistance). Sometimes high temperatures can melt solder connections or cause moving parts to bind or seize.

Good heat sinking on the motor case helps, but heat can only leave the armature so fast, so you can still burn up the motor at high power.

Thanks. I'll give it a try. I can only get to rs on weekends. In the mean time i will play with the last relay i have. I bet i'l just break it, but i need to be doing something.

You can always try my site for ideas on a tachcometer or lap timer.
:) HAve fun

http://www.geocities.com/wdiaz03/miniRCstuff.html

I built a similar device, although mine measures linear speed instead of RPM.

I used the same mouse sensor idea, except I used cut down the base of the mouse to keep the whole axle assembly and the ball contact part of the sensor. I filled the slots and drilled a new hole then mounted IR sensor/receiver pair. The output runs through a small transistor circuit to digitize the output pulse.

Rather than go to the trouble of building a real interface for it (microcontroller and LCD display), I just connect it to the 'scope and to determine the frequency, then multiply by the diameter of the input shaft.

Works well to determine the top speed of the car, although its not very self-contained, since I have to keep the 'scope around to use it.

I've been off of my zzse project for a little while now. I've been playing around with some superslicks because they are larger and bit more forgiving. I miss having the propo controls. I'm getting more comfortable with using FETs. I plan to finish up my superslicks project by MOSFET modding it before I start back on with the zzse. The batteries and motor that I am using in the zzse are more or less the same as what I have in the superslick, so I expect equal and better results in the smaller propo car. The slick had 4 cells running on a stock PCB until I fried the FETs (hence FETs mod). So far the slick gets a top speed of >8mph (average over 10ft with 3ft head start.) I'll be starting new thread in the superslicks section for this car soon.

Even thought I have gotten great results from FET modding a super slick, I still like the simplicity of using a relay. http://www.mouser.com/ has a good selection of micro solid-state relays. The are reasonabily priced. I plan on continuing my experimentation on my zzse on this note.

Mouser is one of my favorite supply houses.

I'm looking forward to hearing what kind of results you end up with.

What are you doing for wheels? I find that with powerful motors I end up doing rather more doughnuts rather than acutal racing.