Servos for Micro:bit

[Jason Mickelson]

Hello everyone:

I am somewhat novice at understanding compatible circuit parts and wondering if anyone has any advice. I have several different types of servo motors that I want to use with students and their Micro:bits. 

I see many tutorials online on how to connect them up and they all seem to work no problem with alligator clips, jumper pins, etc. The blue servo in the photo is the one that won't work. It's also the type I bought a lot of last year through Amazon. Before I source more I'm wondering:

- if anyone has any advice on which servos for sure work with Micro:bit and alligator clips setup (and a link to purchase)

- if I'm just missing something right in front of me. 

I realize some motors have different power requirements but these all look like typical hobby servos. And the other two servos work with just the 3V battery pack. And I don't understand the letter number designations on the labels. 

I can get the blue servos to work when I use a Bit:booster but this year I'm loaning everyone their own Micro:bit and don't have enough bitboosters to go around. So I'm looking for the economical way everyone can still bring motor movement into physical computing inventions this year in hybrid/distance learning mode.

Any help is very appreciated. 

[Kristin Burrus]

This is a helpful article: https://support.microbit.org/support/solutions/articles/19000101864-using-a-servo-with-the-micro-bit

The side of your servo will be numbered (like SG90).  Do a google search and determine how the wires need to be connected.  Different companies wire power, ground, and data pins in different orders with different colors. 

Hope this helps.

[H G]

I am sending Microbits and servos (SG90) along with alligator clips with a male jumper cable end to my students.  You will need 3 of those cables per servo, and I believe the Microbit barely generates enough power for one servo. I ordered both the servos and the alligator clips to male jumper cables (I messaged them directly) from Feetech via Alibaba:  https://feetechrc.en.alibaba.com/search/product?SearchText=sg90

[Diego Fonstad]

I have found that the 2 X AAA batteries that come with the micro:bit Go kits are of varied quality and not properly power a servo (I've had some as low as 1.4V out of the wrapping).  If the micro:bit is plugged into the USB cable, it is drawing power from the computer and can usually power one servo.

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[Diane Brancazio]

There’s so many things to like about the Micro:bit, except the 3V constraint.

 

I help teachers set up makerspaces and create projects, and while I recommend the micro:bit for developing coding skills, it just doesn’t cut it for physical computing because it is not easy to use commonly available servo motors.  I provide battery packs with AA batteries and don’t even bother with the AAA batts.  I can get 2 or 3 servo motors to work briefly, but they drop off too quickly.  Yes, I can add a 6V battery supply separately but that s more hardware and expertise than teachers and students should when learning.

Kitronik in the UK supplies all thing micro:bit, and they only have 5V servos with a variety of connectors or a a servo board that supplies a higher voltage but adds cost and complexity.

https://kitronik.co.uk/products/25105-clippable-servo

https://kitronik.co.uk/products/4178-servo-to-crocodile-clip-adapter-cable

https://kitronik.co.uk/products/46147-servo-kit-for-microbit

 

3V servos would solve the problem.

I haven’t tried these but it looks like you can get them at Parallax, along with tutorials

https://www.parallax.com/product/3v-digital-micro-servo-continuous-rotation-ft90r/

 

Anyone know why the BBC micro:bit developers went this route? 

 

Best to you all and a hopeful new year!

Diane

 

Diane Brancazio | K-12 Maker Team Leader 
MIT Edgerton Center | Office of Experiential Learning  
Room 4-406
77 Massachusetts Ave, 
Cambridge, MA 02139
617-253-2865 | Email | Maker Resources  | LinkedIn  | Twitter

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[Jason Mickelson]

Thank you for the helpful feedback everyone. And helping me confirm some my suspicions about the limits of this setup. 

I have seen so many Circuit Playground and Micro:bit physical computing examples with ubiquitous parts the last two years that I didn't really read between the lines. I agree rigging up a separate battery pack in the middle of creating these circuits for beginning students seem extra. 

I used to use Hummingbirds. But I had so many issues with syncing boards to PCs with Snap and BirdBrain that I had to switch to something else. BirdBrain is so supportive and helpful and we just couldn't find a rhyme or reason to what was happening. It was just too frustrating in the classroom.  I also prefer geared dc motors (dagu motors) for physical computing projects. Kids usually want their robots, etc. to pull/lift more weight. They are bit easier to fabricate attachments for. And I do so many other non-programmable circuits the dc motors work better for. 

For our program I believe the Bit:Booster is a good solution. It brings up the cost of the system but its reliable for power and solid connections and enables multiple motors. It integrates with MakeCode in a way that is 'just different enough' to test their understanding of how to use the blocks with digital and analog signals and values. I will invest in more next year as (fingers and toes crossed) our program (and my budget) comes back to full strength. 

 Thanks again. Hope everyone is taking good care and finding great ways to stay safe and continue making with the kids!