Where do I connect it?

I have an old droid eris and a RAD 2.0, I want to somehow conenct the droid to the motherboard of the RAD by soldering the end of it's usb connection cable but I am not sure where to do this. I have searched the web for a schematic but have been unable to find one. Any advice or resources are welcome. 

Simply put–Not gonna

Simply put–Not gonna happen.  Not the way you’re thinking.

I’ve never gotten any closer to a RAD 2.0 than a store shelf, but if memory serves, they’re pre-USB.  There is no way you’re going to connect your phone to your toy robot as it stands now.

However. . .

There are a number of devices that can be used to connect an android phone to a micro controller, either tethered or wireless.  Typical microcontrollers don’t have the power to control motors, so you’ll need a motor driver board, or, swap the motors with servos.

There’s a guy who sells a robotic microcontroller board, called EZ-B, and also a fairly complete kit of parts specifically designed to transform old toys into fairly sophisticated robots.  I hate to send someone off-site but his videos do a pretty good job of explaining how it all works, and exactly what’s involved in retrofitting old toys into robots.


But frankly, he isn’t doing anything you couldn’t do with a handful of servos (and some other parts–depending on what you want to do.) and an Arduino and some shield or other to connect it to your phone.  If you browse the projects here, you’ll no doubt find someone controlling a robot with their phone, or using their phone as a remote.

Here are a few links to get you started




You should also check out the tips and generally browse the site to start learning the skills you’ll need.  Good luck!

Thank you.

EZ-B is way out of my price range, I hope to make this out of completely salvaged parts but I am willing to spend up to $50 to get it working. I will definitely check out those links and spend some more time browsing the site.

A little more information about my project:

- I had planned to use my droid as the “brain” for my robot and to control it from my macbook pro.

- I no longer use the droid as a phone and consigned it to this project as a way to save it from collecting dust.

- I have no programming experience and my electronics experience is limited to dismantling and cobbling together old electronic toys into frankenstein machines as a child, though I never bothered with the motherboards and just hooked up the motors to batteries.


In case you misunderstood how I wanted to connect the USB, my plan was to cut off the usb end of the cable while keeping the droid end and solder the wires to the motherboard; my thinking was that if it can accept radio frequency commands then it can accept commands from my droid if I replace the connection. There is a port for a phone line, perhaps that can be converted ot recieve USB? 

OK, I can certainly

OK, I can certainly understand “bringing it in at a low cost” as an important design consideration.  I never quite manage to do that–Murphy’s Law being what it is.  But back to your project. . .

I wasn’t (exactly) suggesting you buy an EZ-B.  I have my own issues with that product, tho I do respect it as an easy way to get involved with robot toy conversions.  I was actually pointing you towards the videos, where he starts out with some robot toy from the 80’s or 90’s, takes it apart, pulls everything electrical out of it, puts it through his dishwasher, reassembles it and hot glues servos into strategic locations, and ends up giving them fun and fairly sophisticated features.

If you’re going to keep costs down, you’re going to have to reuse as much of your Rad 2 as possible.  With this in mind. . .

General “instructions” here–I’ve never seen a R2 up close. . .

If you open up your robot and examine the control board, (motherboard is probably not a good description.)  You should be able to find the places where the motors connect.  If you can manage to find the traces on the circuit board and follow them, hopefully they will lead you to a transistor driver that–with a little research and skill, could possibly be connected to and turned on by “something” that will communicate with your repurposed mobile.  Tho. . .

The problem with your Erin is that it uses an older version of the Android operating system, and most of the devices that could be controlled by an Android phone expect v2.2 or better.  I’m not sure what the phone line port on your Rad 2(?) is, but in the days when Rad 2’s rolled about the land–cell phones were pretty much for rich people and there is almost certainly no “easy” way to make the connection.

There is at least one project here, and probably others, where someone is hacking a radio controlled car to turn it into a robotic vehicle.  Glancing at it however, I doubt that it’s an entry level project.


As for your skill set–Hobby robots has its fingers in a lot of pies.  Some general electronic skills are an absolute minimum, and any sort of construction, mechanical or crafting skills you can bring along help a lot.

I still think you’d do better to get an Arduino and a few (really) cheap servos and/or sensors, and start there.  Eventually, you’ll have a better understanding of the details you need to accomplish to complete your project.  I don’t think you should be too impatient to take a screwdriver to Rad 2 yet.  But I do believe that an Arduino, and some time spent on the tutorials will get you much closer to your goal.

Also, for really good prices, check out yourduino.com.  Terry is a member of LMR and YourDuino seems to be in the process of becoming the “official” LMR shop.  send him an email and you can probably get onto an LMR discount list.