Mario's Tronic Joy Based Sim

I am shure Thanos will have a good ansver, but I think 8 turns seems to be way too many. I am experimenting with another setup, and I believe 2-3 turns will be enough! Fred

Hello Fred.

After looking at a wiper motor video on youtube, they appear to turn at 1 rev/s. One revolution would give 45deg of roll. So a range of +45 to -45 deg. would be 2 motor turns. Does that sound semi-logical to anyone or is a 2 second limit to limit speed to fast?

Guess its somewhere between semilogical and logical! I believe when there is load the motor will be slowed down a bit. The point is to find the right blance between speed and torque! When a car (in game) t.ex. brakes heavely, it would be a good thing if you get max g-force as fast as posible!

That's right. Sorry for saying 8-10 turns, I was overestimating their speed.

There is no such thing as too fast if your frame can handle it. To calculate the gearing, you have to measure some geometry values.
First, determine the amount of travel you want. For example, lets say 45deg in each direction, so that is a 90deg range. Now you take the point where you connect the belts to the frame. That gives you the radius of the rotating arm, and you can calculate the circumference of that circle for 90degrees.

This will be your distance from one endpoint to the other, the distance your belt has to travel. For example, you calculate this distance to be 50cm. If you have a pulley with a circumference of 5cm, you will need 10 turns of the pulley to achieve this 50cm motion of the belt. In turn, your belt moves the cockpit -45deg to +45deg.

It is actually easier to draw than explain.

Hello Frakk. I understand exactly what you are saying. It would be great to have 50cm travel in each direction! :clap:

Check out this video Im sure you have seen before.


The motor appears to turn approximately 1 turn per second.

Since Im limited to 12v, my assumptions for rotation are based on this angular velocity :?

This is whats crossing my mind. Any opinions and suggestions highly appreciated.

Considering substituting towers for something hidden inside the base.

Your bottom drawing I was going to suggest, much better for stability. With a vertical tower you will stretch the belt due to the circular movement of the frame, and that will push the frame to the side a bit. Having the pulley on the bottom will only pull it down, making it more stable.

Thanks for the positive feedback Frakk. The only reason Im considering an alternative is because of the cost to make the towers. That L shaped bracket material is very expensive here. Plus the cost of screws and nuts as someone else once said in this forum. Adds up fast!
I figured I have to get 3 pulleys for each tower anyway. I will try it since The loss would be in making a small bracket for the motor and possibly a belt. The pulleys can be re-used to make a tower if all else fails.

I would do a 30mm cog and 200mm gearbelt pulley combo (6.66:1 ratio) with the pulley centered on a caster but the mass moment of inertia about the center of rotation is considerably high. Time to order some motors.

I found this information about my wiper motors. Thought I would share it as I am confused as how to wire for hi speed. The chart to the right gives approximate speed, current draw and power supply hookup information for counterclockwise motor rotation. As an example, if you want the motor to rotate at 70 rpm, hook the positive (+) connection of the power supply to the High speed terminal of the motor and the negative (-) connection of the power supply to the Common terminal on the motor.

You can reverse the direction of rotation by reversing the power supply connections (use caution as the motor casing is tied to Common).

NOTE: This motor was listed by many sellers as having two speeds, 106 and 41 RPM. Technically, this information is incorrect as the motor was not designed to be run at 106 RPM. It can be wired to run at that speed, and I give that information at right for reference only, but I cannot recommend it.

RPM Current draw** + pwr supply - pwr supply
41 0.9 amps Low speed Common
70 1.6 amps High speed Common
106* 4.0 amps High speed Low speed

*Hookup details for 106 rpm as information only.

**No load current. These numbers will increase as the mechanical load increases.

On my wiper motors I get almost 6 amps with no load...

With load I get up to 15 amp !!!!

Read about this here:
wipermotors-overvoltage-increasing-speed-t2329.html

You should connect your motor for LOW Speed.

As I posted before, you are compromising torque by increasing speed, and you are also increasing current significantly.
Without sufficient torque, you cannot have speed. A low torque/high speed motor will only heat up trying to move a heavy load. It will NOT be fast, because it doesn't have the power to accelerate a load that fast, it will never reach the top speed, or even half of it's top speed.

With a high torque/low speed motor you can get up to maximum speed much faster because you have the power. Because of this the response is much quicker and more accurate. The top speed will not be that high, but it will be faster than the speed you would get in the previous scenario.

I also wouldn't worry about the motor's datasheet too much. Once you have all the weight on them, you can throw these no-load numbers out the window. The RPM will drop, current will increase, and not in a linear way, so you can only guess the outcome.

Hello guys. Well I went to the junk yard yesterday and looked for the biggest worm gear wiper motor I could find for cheap. The 85 Nissan motors are going for about $40 each. Newer motors are less. I got a deal on 2 1995 toyota camry motors that I couldnt pass up. Paid $36 for both plus 3 pulleys and 3 belts.

Thanos- Im assuming the goal is to get a high amp draw motor so so the power output in watts is highest? I have to borrow an ammeter to check no load current draw.

Frakk - I was under the impression that people were seting up their motors at high rpm. Thanks for clearing that up for me. I just checked my toyota motors. At the low speed setting, Im getting 48 rpms in both directions. On the high speed setting, I didnt measure the rpm but its definitely faster in one direction than the other but only at high speed. Therefore, low speed it is. Looking for torque!

Today I built a tower out of wood for the cockpit for aft rotation. The drilled angle irons are expensive here so I made one out of scrap wood and it appears it might work. I mounted up the pulleys to motor and tower top and am pleased with the rigidity of the structure. But then again riding in it might be a different story. I will post pictures soon.
Now while I wait for the pcb's to arrive, Im going to try something different with the gimbal motor. Going to try to use the junkyard parts I got, timing belt and cam pulley instead of vbelt and going towerless on the gimbal like the sketch I posted earlier.
I spent hours in the junkyard measuring pulleys and motors. I love that place!

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$36 for all that, wow.

You got a really good deal. I should look for some junkyards too...

Have you ordered your mosfets yet? Use logic level mosfets for the bottom N-channel ones, otherwise they will heat up and limit your power.
russian-2dof-wiper-motor-simulator-t2299-30.html#p22793

Pictures or videos are welcome!

ps. you can edit your post after you submit, top right corner - edit

edited

Those mosfets require at least 8-10Vgs to turn on completely. In the DMShb the lower n-ch mosfets are driven directly from the 74HC08, only 5V and they will waste a lot of energy heating up and limiting the power.

The IRLZ44 is better because it is a logic level mosfet and only requires 5Vgs to turn fully on.

edited

Finally got the AVR to read/write fuses and program on 22mhz. I am so happy thats over. It turns out I had made a mistake in the soldering connection of the crystal socket on the board. There was no contact as the pin was not through the board fully and touching solder. I had to trace every line to find this as it wasnt apparent to the eye. Major mistake on my part. Ponyprog works perfect and so does Thanos' AVR ISP programming circuit which I know from memory by now.

Anyway, now the LCD doesnt work. It wont display data after programming only black blocks. Stay tuned...for more problems. :thbup:
Still to come....Hyperterminal problems! :clap:

Good news Mario!

I recommend you use the 14.745600MHz crystal or 16.588MHz tops. The At8535 has a maximum 16MHz clock frequency, depending on the batch it will be unreliable above that.

Black blocks on the top line mean the LCD is not initialized. Double check your connections and the compatibility. The LCD should have a HD44780 controller or equivalent. The most common module is the 1602, it should be printed on the back of the screen. Also enable the LCD on the DIP switch.

Thanks


mario