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Hardware / Re: Phototransitors power supply
« Last post by Green 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 / Phototransitors power supply
« Last post by exapod on October 14, 2014, 02:14:31 AM »
I have a doubt about the phototransitors power supply. In my mouse i have a very small regulator max 30 mA powering the analog part of the mouse (Gyro and phototransitors) but my doubt is if 30 mA is enough or the phototransitors consume more power.

Hardware / Re: Where I can purchase IR sensors?
« Last post by Green on April 29, 2014, 03:28:58 PM »
digikey, mouser, likely
Hardware / Where I can purchase IR sensors?
« Last post by Young on March 23, 2014, 10:43:11 PM »
I know the part names of IR sensors from this site, but I could not find where they are sold.

Please get me some recommendations of IR sensors and sites where I can purchase them.

Thanks in advance.
Hardware / Re: Help with my first mouse
« Last post by Green 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
« Last post by exapod on September 19, 2013, 01:30:44 AM »
0,3 mm resolution means that if i read the encoder X4 and with a gear ratio of 1:4 i will have a count every 0.3 mm.
The 17 mm wheel is without tyres, i've read that some mice have 22 mm diameter wheels with the tyres and i don't know where to buy them, the mini z wheels that i have are 20 mm without the tyres and 25 mm with the tyres.
I will mount an accelerometer somewhere, do you have some information on how to use the two sensors (accelerometer and gyro) to control a mouse ? I guess that i have to integrate the acceleration to get the speed and in a straight trajectory is simple, but when the mouse is turning things get a little complicated... do you know someone else who is using the accelerometer?
Hardware / Re: Help with my first mouse
« Last post by Green 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.
Hardware / Help with my first mouse
« Last post by exapod on September 19, 2013, 12:47:27 AM »
Finally i have some time to spend on my first micromouse but i have some doubts and questions.
I will be using the fauhaber 1717 with 16 line per rev encoder and using the 4 wheel configuration.
What is a better distance from the floor: 1,5 mm or 2mm?
Does someone knows where to buy 17 mm mini-z wheel?So the ending wheel will be 22mm.
In your opinion a resolution of 0.3 mm on the floor is enough to control a robot? i will also mount a gyro.
Should i mount an accelerometer to help the resolution or it is just impossible to use in such application?
With this low resolution you reccomend using 4 or 6 sensors?
This question is for the admin, i read that for your new mouse you have a gear ratio of 11:40, that is 3.63636363... how do you deal with this numbers? You use float or fixed point integer?
Thank you for the help and sorry for all this question :D
Electronics / Re: check out my break out
« Last post by Green on September 04, 2013, 10:07:54 PM »
that looks really cool! good work!
Electronics / check out my break out
« Last post by LosAngelesLee on September 04, 2013, 02:00:28 PM »
I made a break out board of the Freescale k20. It is the same circuitry as the Teensy 3.0 minus some of the filtering components. The second processor on the board is one that I had to buy from Teensy. Apparently it has a program on it to make the chip compatible with the Teensy modified Arduino IDE. But the USB goes staight to the K20 chip' so I am hoping I can still program it using Freescales Codewarrior IDE using assembly language.

The PCB was made by Oshpark. They are quick with turn around times of two weeks. The biggest difficulty using them was getting their online design approval software to approve the greber files. I have not used anyone else so I have nothing to compare it to. Oshpark has a .dru (design rules) file to help with checking the design in Eaglecad.

 I would like to change the smaller pads for the 0805s(the resistors) And longer pads for the QFP (the k20 chip).

Continuity and checking for shorts was done with a multimeter.  But I have not received the header pins yet. So no programming testing.

See anything you like or dislike?

 :(********warning, I never could get this to work correctly. Maybe you all can still find this useful***************
I ended up just going back and am currently learning 8-Bit Atmel AVRs. Using AtmelStudio6 for an IDE and a Atmel Programmer instead of a bootloader and FTDI.
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