We do 'reverse engineering' our whole life
and only sometimes get pleasure from it.
5. Cording for simple IR toys.
5.1 Battle Tank.
Let's start with a simple one - the "battle tank" remote control.
Operates on a standard 38 kHz sub-carrier, transmits only when a button(s) is(are) pressed. After releasing the button, it transmits three more codes. Interval - 80mS.
If we stretch the code in time, for example L-Fwd (Left-forward), we will see the following ('high level' - no carrier, 'low' - 38 kHz is ON).
The figure shows the time intervals. The coding of "zeros" and "ones" is similar to the idea contained in the TX5 set. The transmission of each bit begins with a sync pulse. If it is followed by a long pulse, then it is “1”, if pulse is short, then “0”.
The following picture (from logic analyzer) shows how this happens in real life.
After the start pulse, 13 bits are always transmitted, of which:
- first 3 - toy number;
- the next 7 - "on-off" information;
- last 3 - checksum (simple sum of "1's" in the transmitted sequence).
And as an example - a sequence when several buttons are pressed together.
And as an example - a sequence when several buttons are pressed together.
Forbidden combinations ('left forward' and 'left back', simultaneously) turn into code combination "13 all Hi", or are ignored for transmission.
*** Any inaccuracies on this page will be corrected if you let me know (e-mail is highlighted next :) ***