TRRSTAN kit Contents
TRRSTAN is now for sale on the inventor’s site: robots.allthingsgeek.com
The TRRSTAN kit is designed to meet three main goals:
- Affordability, currently $48, batteries included, $40 Educational. So cheep you can get two and fight em!
- Simplicity, Avoids programing microcontrollers, lets you concentrate on programing the phone instead, audio connector allows control from any device with a headphone jack.
- Upgradeablility, Because makers like making things more then having things, provide upgrade options for future tinkering
The physical design of TRRSTAN uses the PCB as the chassis, CDs for drive wheels, and nylon shower door rollers for rear wheels. This gives it an overall look similar to a roman chariot. Smartphone jousting anyone? CDs wheels were chosen so they could be made from CDR coasters or unwanted Hana Montana albums. The large diameter makes it a pretty fast bot. The phone is held on with rubber coated screws and an optional Velcro strap.
The electrical design of TRRSTAN has two main circuits. For power their is a TI boost/buck regulator that accepts from .8V to 6.5V and provides a constant 5v at up to 1500mA, depending on how far it has to boost. It also provides a low battery led and overheat/short protection. It is supplemented by a low VF Shockley Diode, which provides up to 3A directly from the battery if the 5V line drops due to high start-up loads. The kit currently ships with two AA batteries and a holder, which keeps cost low.
The second circuit controls the servos via the audio. The software on the phone generates a pulse width modulated signal that travels to the board via a standard 3.5mm TRRS(tip-ring-ring-sleeve) headphone+mic cord. Then a Toshiba quad opto-coupler to rectifies the +- pulse of the audio signal, boosts it to 5v and squares it off. With some servos you do not even need the boost from the opto, you can drive them directly from the headphone cord. However, the opto also provides electrical isolation to protect the phone if something bad happens.
TRRSTAN Schematic
There is also space on the board for a sensor upgrade kit that allows two 0-5v sensors, two quadrature encoders, two bump switches, and sends data back to the phone via the mic line. This sensor upgrade kit does use an 8pin AtTiny13. This upgrade kit is still in development.
TRRSTAN is now for sale on the inventor’s site: robots.allthingsgeek.com
Ready To Rock
