# Critique my design: CubeSat reaction wheel demo

**URL:** <https://community.simplefoc.com/t/critique-my-design-cubesat-reaction-wheel-demo/7492>\
**Category:** community projects\
**Tags:** bldc\
**Created:** [July 27, 2025, 5:48pm UTC](https://community.simplefoc.com/t/critique-my-design-cubesat-reaction-wheel-demo/7492 "2025-07-27T17:48:51Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Cormac\_McCarthy](https://community.simplefoc.com/user_avatar/community.simplefoc.com/cormac_mccarthy/32/8965_2.png) [@Cormac\_McCarthy](https://community.simplefoc.com/u/Cormac_McCarthy)\
**Post date:** [July 27, 2025, 5:48pm UTC](https://community.simplefoc.com/t/critique-my-design-cubesat-reaction-wheel-demo/7492/1 "2025-07-27T17:48:51Z")

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Hello all,

I am new here, is this still an active community? I wanted to use parts listed on this site for my project but many of them are no longer sold.

Anyway, I would like to share what I am doing and get some critiques because I honestly have no idea what I am doing.

So here’s the project:

I am designing a demo of 3-axis satellite pointing using reaction wheels.

Parts list:

MC: Adafruit MetroM4 Airlift Lite  
IMU: Adafruit BNO055  
Motors: 3x RCTimer 90KV Gimbal Motors  
Motor Drivers: 3x SimpleFOC Minis  
Encoders: AS5048A Magnetic Encoders  
Power: 3S LiPo Battery, 5V step-down regulator (for MC power)  
Various 3D printed components

The attached schematic is mostly to help me visualize and I’m certain I violated a thousand conventions in it but if you can look past that I would appreciate critique if you see any glaring issues with the setup. Also if you think there will be any compatibility issues with the components I am using; most of them have not arrived yet.

Thanks for reading!

 ![CubeSat Electrical Schematic](https://community.simplefoc.com/uploads/default/original/2X/1/135e3de2df074038fe5094c3b495c48f1a8543fd.png)

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<div class="post-metadata">

**Author:** ![iso14000](https://community.simplefoc.com/letter_avatar_proxy/v4/letter/i/ebca7d/32.png) [@iso14000](https://community.simplefoc.com/u/iso14000)\
**Post date:** [July 29, 2025, 2:40pm UTC](https://community.simplefoc.com/t/critique-my-design-cubesat-reaction-wheel-demo/7492/2 "2025-07-29T14:40:56Z")

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in green =\> ambiguity

in red =\> errors

no decoupling/reservoir cap, floating pins, floating gnd, lack pull up on I²C lines etcetc….

 ![ciritical](https://community.simplefoc.com/uploads/default/original/2X/9/9e75731041f25b7bb61c28668f3e8923d55575cb.jpeg)

best regards

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<div class="post-metadata">

**Author:** ![Cormac\_McCarthy](https://community.simplefoc.com/user_avatar/community.simplefoc.com/cormac_mccarthy/32/8965_2.png) [@Cormac\_McCarthy](https://community.simplefoc.com/u/Cormac_McCarthy)\
**Post date:** [July 29, 2025, 11:16pm UTC](https://community.simplefoc.com/t/critique-my-design-cubesat-reaction-wheel-demo/7492/3 "2025-07-29T23:16:56Z")

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Thanks for taking the time to respond. I have 1 decoupling cap in there but are you saying I should have one for each motor? Also the BNO055 is on the adafruit breakout board so no external pullup resistors are required.

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<div class="post-metadata">

**Author:** ![iso14000](https://community.simplefoc.com/letter_avatar_proxy/v4/letter/i/ebca7d/32.png) [@iso14000](https://community.simplefoc.com/u/iso14000)\
**Post date:** [August 1, 2025, 7:34am UTC](https://community.simplefoc.com/t/critique-my-design-cubesat-reaction-wheel-demo/7492/4 "2025-08-01T07:34:00Z")

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usually when a review is scheduled, it is necessary to give, at least , all datasheet (or links to)

please redraw your design, remove power lines from bus, gnd shoud be … bottow oriented and not hanging like a bat 🙂 . Enable lines for drivers should be pull downed by resistance to gnd.

there is definitly lack of decoupling caps , and reservoir caps..

don’t know what is your regulator,

you should segregate the power for BLDC and power for digital ,

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**Author:** ![Valentine](https://community.simplefoc.com/user_avatar/community.simplefoc.com/valentine/32/1024_2.png) [@Valentine](https://community.simplefoc.com/u/Valentine)\
**Post date:** [August 4, 2025, 3:42am UTC](https://community.simplefoc.com/t/critique-my-design-cubesat-reaction-wheel-demo/7492/5 "2025-08-04T03:42:35Z")

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> [@Cormac\_McCarthy](#):
>
> is this still an active community

Yes.

Cheers,

Valentine