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Hardware / Re: Phototransitors power supply
« on: December 13, 2014, 07:24:26 PM »
it is sufficient if it only supplies the IR receiver.
Just assume the resistance of photo-transistor becomes zero when max IR is received. It will draw about 2mA current when serial with 1.8K ohm resistor. 30mA might not be enough if it also supplies the gyro.

Hardware / Re: Where I can purchase IR sensors?
« on: April 29, 2014, 03:28:58 PM »
digikey, mouser, likely

Hardware / Re: Help with my first mouse
« on: September 20, 2013, 06:52:46 PM »
current the resolution per mm for my new mouse is 97 counts per mm
They customized wheel on their own for those who had 22mm diameter wheel.
If you maintain of using low resolution encoder, accelerometer will be your feedback for forward motion control and gyro will be the feedback for rotational feedback for rotational movement.
So far I only know Kojima use accelerometer as forward speed feedback since he only has low resolution encoder only to count distance.

Hardware / Re: Help with my first mouse
« on: September 19, 2013, 01:02:47 AM »
   16 lines for 1717 is terribly low to keep track of the speed unless you use accelerometer to monitor the velocity and use low resolution to count distance only.
1.5 is better,  not too much big difference with 2mm. It's better if you can make the mouse MUCH lighter instead.
I never seen 17mm wheel. You will have to make you own wheel either by lathe/CNC from a POM/acetal or high resolution 3D printing.
what does 0.3mm resolution mean?
gyro is required for a 4 wheel mouse otherwise the mouse won't be able to turn with only encoder.
Accelerometer is needed if you stick on low resolution encoder. The winner of half size micromouse, Kojima, use low resolution encoder accelerometer combo for his mouse, although it is not as comfortable as high resolution encoder to use.
Now 4 sensors and 6 sensors worked same for me. side sensor isn't that useful if you can tune your mouse well. Besides, less sensor equals less sensor pulsing time.

As of the gear ratio. I was just trying to get a little bit higher torque than my old mouse with 12:40 gear ratio, kinda came out of random, haha. It also helped me to lower the CG without making 2 wheels too close. The gear ratio won't really get involve into computation when mouse is build. I only use encoder counts per cell instead of caring the gear ratio and wheel size.

Electronics / Re: check out my break out
« on: September 04, 2013, 10:07:54 PM »
that looks really cool! good work!

General Discussion / Re: Straights without walls
« on: March 26, 2013, 03:53:38 PM »
for question 1: post error usually smaller than wall error even though they are at same distance. No way to distinguish them if you don't want to make your PID be complicated. The point is your mouse should be able go straight without sensor at first place(by using encoder and gyro), then add sensor error to your total error. Most of the time my mouse just ignore the post since the reflection area is smaller than a whole wall, it actually makes your mouse perform better at fishbone, but you need to make mouse go straight with sensor first.

question 2: i made offset fairly small, that's actually some threshold I use to determine if there is wall or no wall for floodfill.I use 2 Boolean to switch the status(one for left wall the other for right wall), my diagonal offset is likely 200 out of 4096 ish, since my sensor reads pretty far. You need to test out based on your own mouse

Natcar / Re: what is the difference between 5 sensors and 3 sensors
« on: December 09, 2012, 04:18:49 PM »
There is no such advantage or disadvantage between 5 sensors and 3 sensors. It's most likely different people's preference. Typically, 3 sensors will make the car work good enough as long as the inductor you choose will have signal overlap to each other.

Natcar / First Post here, Feel free to ask and answer questions here.
« on: December 08, 2012, 09:54:33 PM »
hello, fellows.
    I'd expect all your problems will be solved within 24 hours, enjoy and have fun.

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