Original Magic Trackpad - Wired?

[cosmichobo]

G'day,

I'm not a fan of buying near-future-E-waste, so am still using an original, AA-battery powered Magic Trackpad, rather than the Magic Trackpad 2 with non-replaceable battery.

This still however either involves using single-use AA batteries, or rechargeables (which I opt for).

Given that there's people out there who have created hacks to use memory cards to replace hard drives in old Macs, and even little PCB boards to generate HDMI output for the Nintendo Entertainment System - surely someone out there has made a hack to "wire up" Apple's original Magic Trackpad?

USB (2) is 5v, but I expect could be stepped down for the trackpad's 3v requirements?

Has anyone ever seen this done?

Cheers

cosmic

 

[Needleroozer]

surely someone out there has made a hack to "wire up" Apple's original Magic Trackpad?

The most popular route is to make something that takes the physical place of the AAs and steps the 5V down to 3V or so, either using series diodes’ 0.7V drop or by using a linear regulator of some sort.

USB Powered Magic Trackpad

www.synack.net

USB Powered Magic Trackpad

Batteries on the Magic Trackpad last an amazingly long time. I would say about 6 months for my usage (on alkaline cells). Nevertheless, eventually running out of batteries is always annoying so the…

bounav.wordpress.com

There was even an unsuccessful crowdfunding campaign:

https://www.indiegogo.com/projects/usb-power-adapter-for-apple-trackpad-and-wireless-keyboard#/

USB (2) is 5v, but I expect could be stepped down for the trackpad's 3v requirements?

The iFixit teardown does not provide part numbers for the two switching regulators on the board, but U3 is marked BQA, matching a TI TPS62510 step-down converter. U9 is the other regulator, and its BHT marking matches a TI TPS61045 step-up converter. Since U9 is by one of the flex connectors going to the trackpad and is a step-up converter, it is more likely that U3 is the input voltage converter.

https://guide-images.cdn.ifixit.com/igi/KRCORLvIsTe2Z41q.full

U3’s absolute maximum input voltage is 4V, and it is designed to function from 3.8V down to 1.8V in normal conditions, so powering the trackpad circuitry directly with 5V is not recommended, although it may work for a while…

I have a Magic Trackpad that needed some destructive surgery to remove swollen and corroded alkaline batteries, and so I took it apart so I could run it off an external battery (a LiPo in my case, putting a single 0.7V rectifier diode in series to drop the maximum 4.2V down to a safe 3.5V). I was able to power my trackpad by soldering on to the BATT test point and the ground side of C71. I drilled a hole in the bottom of the trackpad plastic housing to let the wires out.

 

[cosmichobo]

I actually have 2 Trackpads. The first one, the pads came out due to a kid and blutak... I might give it a go on that one first and see how I go!