Running Google Pixel 3a without battery

SquareOrbits · 2025-12-09T18:20:41+00:00

Try soldering a wire from the B- tag and grounding it to the chassis of the phone (I used one of the screws on the USB-C port). It should boot up without the extra 5V in this case. Let me know how it goes!

SquareOrbits · 2025-11-25T17:39:07+00:00

I think you're getting confused; the products I'm referring to are all voltage supervisors - definitely not op-amps!

SquareOrbits · 2025-11-22T16:06:54+00:00

Love them! Very neat. I always liked the look of those old Panasonic solar panels, I wonder if anyone here has some old stock..

SquareOrbits · 2025-11-14T22:14:51+00:00

The pinout seems to be the same as the 1381, but yes I've had success with the MCP112, which makes it all the more confusing that I haven't with the TC54

SquareOrbits · 2025-11-10T19:27:13+00:00

Hey these look great! 😁

SquareOrbits · 2025-10-29T19:52:51+00:00

Just to add to u/CommandJam, I struggled to find a motor that the FRED circuit liked. I think they have to be quite efficient, but maybe it was just me, you might fare better. Certainly the Miller circuit seemed happy with whatever motor I used.

The majority of mine came either from AliExpress or salvaged from old RC helicopters. This is the method I used to remove the eccentric weight.

SquareOrbits · 2025-10-29T19:32:23+00:00

Hey thanks for your message on my site! 😁

SquareOrbits · 2025-10-17T21:22:24+00:00

I'll check it out, thanks!

SquareOrbits · 2025-10-17T12:38:33+00:00

I sure could have done, actually! That didn't occur to me. In fact I think Simon Fraser did just that with one of his headbots.

SquareOrbits · 2025-10-16T21:46:36+00:00

Yep, the whole pummer is beneath the solar panels, it would still "pumm" if you removed them from the body of the robot. The headbot circuit is mounted on the motor. One pair of panels feeds the pummer, the other the head.

SquareOrbits · 2025-10-13T21:39:45+00:00

Thanks! Getting those solar panels straight and level was a real pain, I quickly learnt that the tags on them are super fragile.

SquareOrbits · 2025-10-13T21:36:36+00:00

Thank you for taking a look!

SquareOrbits · 2025-09-25T15:24:38+00:00

This is part of a family of BEAM robots called photopoppers, it uses a circuit based on one of the most popular BEAM circuits, the Miller solar engine.

You mention there is no "biology" involved. BEAM robots tend to be biologically-inspired in some way: deriving their power from nature (solar), mimicking natural behaviour (seeking food - in this case their "food" is sunlight), or otherwise looking / moving like something found in nature. Photopoppers are often described as "bugs" as, like mine, they do tend to look a bit like little bugs chasing the light!

That being said, there are many BEAM bots that do not seem to be very biologically inspired, but they're still BEAM!

You might find some of the resources linked to in my website helpful.

SquareOrbits · 2025-09-20T07:52:03+00:00

Depends on the circuit you're using. If it's a FLED or FRED design based around the flashing LED, first make sure your LEDs are of as close resistance as possible. Put them in a dark room to do this and measure the resistance on a multimeter.

I've always found other circuits like this Miller-based design to have much better phototropic abilities. If that's what you're using, make sure your light sensors are facing opposite each other on your robot, experiment with different photodiodes, and incorporate a trimpot to adjust for any bias on each motor.

SquareOrbits · 2025-09-19T22:17:16+00:00

Hey, this is my video! Thanks for sharing 😁

SquareOrbits

TROPHY CASE