Update: for adapted Wild Things please have a look at RJ Cooper’s version:
https://store.rjcooper.com/products/the-coopercar-2
I originally posted about our initial hacks to the Fisher Price Wild Thing here. Since then we’ve built custom versions for several kids and made some upgrades. It feels much more like a polished product now. Also some parents have done a really amazing job further customizing the Wild Things after delivery. Here’s some videos courtesy of Amy McCluer showing her son Braylen riding one. Braylen is controlling the forward and Amy is controlling the turning via the remote control we designed. Later when Braylen is ready he’ll also have switches or a joystick for the turning. Amy will always be able to override with the remote control as a safety.
Amy made the seating modifications for Braylen to be comfortable and secure as well as creating the tray for any accessibility switches to be mounted on. She also wrapped the original plastic wheels with rubber from a bicycle tire for much better traction on a variety of surfaces and grades. Here’s a video showing that in more detail and some pictures:
One upgrade our more recent deliveries include is a 3D printed remote control designed by Robert Haleluk of PrintParts:
Robert Haleluk was able to design and print this remote control enclosure for us even without any modifications to our current circuit board which we had several left of. That wasn’t a simple job since that version of our PCB was never intended nor designed to be mounted inside an enclosure. Here’s what the PCB looks like sitting inside the enclosure.
Our customers think it came out amazing and we agree. But we’re looking forward to the next version which should be even better. As we get ready to do another run of boards we’ll be free to tweak the PCB design and plastic enclosure design together. The result will be phenomenal.
Another upgrade we worked on is a lit power switch on the vehicle with all wires concealed. The lit switch makes it easy to see when the device is still on, an important reminder to turn it off before adjusting seating or getting the child into or out of the vehicle. Also having as many wires as possible concealed is important since many kids will intentionally or unintentionally pull on them. Note that the original toy does not have a power switch. Below are pictures of how that turned out:
Bob's Electronics Projects 
Thanks Bob. Braylen is loving the toy!! It really works perfectly as a light weight but fully functional power chair that will go off road and through the rough amazingly well. It does exactly what I hoped it would. We are very happy with it. Thanks again for everything!!
This is a GREAT upgrade! I think the tray and the push buttons are an amazing idea. Great job!
I have the blue wild thing and the switch under the seat won’t work. I’ve looked EVERYWHERE for one, cleaned it, etc. Is there anything I can do to bypass it? Thank you!!!
Sorry, I don’t have a great solution for you. Fisher Price may be able to send you one or even replace the vehicle. You could maybe bypass it with the info on my site, but in general there are safety reasons not to bypass it. It is easy to hit the joysticks while playing near the vehicle and then it would start moving without a driver. Sorry I couldn’t be more help.
Hello, I have a few questions regarding the wild thing upgrade. My 3 year old daughter has CP, and is unable to steer her Wild thing. She can push the tube I’ve made to connect both joysticks, but that only allows forward motion and occasionally reverse. I’m very interested in getting a controller to be able to steer the machine for her while she goes forward and backward. Is this something you could help me with? I’m very mechanically inclines and good with electric as well. Just really never got into this type of electronics before. Is this a kit I could purchase from you and with directions for install? I’m looking to get this done ASAP, thank you for your time.
Unfortunately we don’t have the bandwidth to put together kits at this point, let alone with proper instructions. But, the job is greatly simplified if you get one of these:
https://letemplay.com/index.php/wild-thing-adapter/
Then you setup an ability switch or two for your daughter, and use other ability switches for your use for the turning. For functions you both are to control you can use a Y-splitter so more than one switch can control it. Your switches you can hold or attach to the rear of the vehicle. These could also be wireless switches.
Taking it a step further you can use an off-the-shelf Bluetooth game controller, and setup an Arduino or Raspberry Pi as the receiver and have it produce the necessary switch closures for each direction based on what you press on the controller. Producing a switch closure with a solid state relay or a mechanical relay is very easy to achieve. I’ve done this type of Bluetooth controller setup before and may do a post about it soon.