SAFETY: Adapting equipment voids the manufacturer's guarantee, and the attempt may cause irreparable damage. Always use adapted equipment under supervision, and disconnect any batteries when not in use. These adaptations are at your own risk.
Hitari 'Tumbler' Radio Controlled Cars cars are long discontinued. The 2 push-button controllers needed here are rare, being replaced by a "full function" controller in July 2000.
N.B. Full-function Tumblers can be adapted for 2-button use but require a replacement handset and car receiver PCB. Tyres marked L-30060 and R-30061 are desireable. Newer stickier tyres L-30060A and R-30061A will need a band of electrical tape wrapped around them to reduce friction or the car will struggle to spin on the spot.
You can take guidance from the following steps to adapt most push button radio controlled toys. Just make sure that there's room in the casing to fit the socket. If not, you could try bringing a lead out of the casing.
Buy pre-adapted: You can buy ready to go adapted Tumbler's from the OneSwitch shop.
Unscrew and remove the rear battery cover. Remove the three fixing screws at the back of the case (1 is often under some stickers in the battery compartment).
Remove the top cover. Make a small pilot hole, using a soldering iron or sharp point. Drill a 1/4" hole exactly as pictured.
Drill a hole on the opposite side exactly as pictured.
SW1 is SPIN.
SW2 is STRAIGHT FORWARD.
As not all sockets are connected alike, you will need to find which 2 of the 3 contacts you need to solder to.
Attach a test lamp or multimeter to any 2 contacts. Plug in your switch, then press it. If the lamp comes on when pressed you have the right connections, otherwise try a different combination. There's only 3 possibilities.
Solder two 13cm lengths of wire to the socket. Expose the ends, tinning them if you wish.
Repeat this for the 2nd socket.
Unscrew the ariel (top right), and the 2 fixing screws on the board. Note the 2 switches above SW1 and SW2.
Flip the Printed Circuit Board over and locate the underside of the switches SW1 and SW2.
If you have the batteries connected, then touch two encircled points together with a short piece of wire. If you activate the car then you've found the right places.
Carefully solder socket SW1 and SW2 to the board as pictured.
Blow on the board to cool it down as soon as the solder flows. Too much heat could damage the workings of the radio control unit.
Tightly screw in the sockets as pictured - avoiding twisting your wiring. Screw the ariel and PCB back in place. Carefully fit the casing back together, avoiding snagging your wires.
Test the car with switches several times, then leave it alone for a few minutes. If it activates by it's self repeatedly, there's probably a short circuit. Pull it apart again, and examine the accuracy of your soldering carefully, especially on the socket.
Don't worry if occasionally the car activates by itself. Hitari Tumblers are known to do this from time to time.
It's quite easy to make any radio controlled car stand out better for people with a sight impairment or tracking disability.
Simply attach glow-stick, glow-laces, helium balloons or el-wire (as pictured) to the car. See more at the Tumbler-Tron page.
Text and images PUBLIC DOMAIN 2003, 2009 - www.OneSwitch.org.uk
Tumbler (c) Hitari - www.Hitari.com