Nikko C1069C protocol reverse engineering 

I have did some reverse engineering on one of my old Nikko transmitters which is based on the Nikko C1069C ASIC.

My plan is to get rid from the old transmitters and emulate the protocol in a 27 Mhz PPM transmitter with an MCU.

Here are my findings:
The IC sends out the encoded serial signal on pin 2.

Frames sent out with ~30 ms interval.

The frame could be separated to 3 segments:
1st is the steering:
- If steering is in norminal state 168 us L, 1433 us H is sent
- If steering is in right state 168 us L, 3706 us H is sent
- If steering is in left state 168 us L, 252 us H is sent

2nd part is the motor:
- If motor is in norminal state 168 us L, 1433 us H is sent
- If motor is in forward state (no turbo) 168 us L, 252 us H is sent
- If motor is in backward state 168 us L, 3706 us H is sent
- If motor is in forward turbo state 168 us L, 252 us H is sent 168 us L 500 us H is sent

There is a 3rd optional segment the horn:
- If the horn/whatever else button is pressed 168 us L 500 us H 168 us L 500 H sent.

There is a static end part:
- 168 us L 500 us H 168 us L -> H


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Noname ("Made In China" ) 320A brushed car ESC from EBAY teardown and reverse engineering 

Some time ago I have bought a low cost ESC for my Tamiya Thundershot from Ebay. Something like this one:


I was always curious about the internal of these stuffs, but I never find any documentation about things like this.

MCU: EM788P153 (OTP)
FETs: 6 IRL3803 (2x2 parallel in forward direction, 1x2 in reverse).
Holtek HT7150 LDO for servos in SOT-89 package. In some ebay shots I can see modifications around that area with a DPAK LDO.


Update: revenged power stage.
Looks like it has a 20V step up converter, an using an LM339 in comparator mode to drive the FETs.
Also notice that it has a dedicated direction where 4 FETs are used while in reverse only 2 but this operation mode is when you drive the negative to the red motor cable and the positive to the black one!:


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Android Studio - Waiting for device @ Ubuntu 

I have started to develop to Android on Ubuntu.
At my first attempt when I have tried run my app on the device, the device shown up as ?????????? in the Android Studio Choose Device dialog.

The problem root cause is the access rights around the device descriptors.

The ADB daemon is started with the user's permissions, so I had created an udev rule to get access to the device:

mm@lapos:/opt/android-studio/bin$ cat /etc/udev/rules.d/51-android.rules
# Concorde tablet (18d1:0003)
ATTR{idVendor}=="18d1",ATTR{idProduct}=="0003" MODE="0666"

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Tyco Terrain Twister reverse engineering 

I have a Tyco Terrain Twister without transmitter.
The demodulated signal encoder in it is on a small board on board PCB.
Unfortunatelly there are not any useful information about it on the web (how the encoding is works etc.).

I am planning that I will replace it with small AVR/PIC based custom circuit whihc capable to encode PPM signals

The RF receiever is also in a separate circuit it was manufactured by the Jetta Company Limited.

I have desoldered the encoder circuit and reverse engineered its pin's function:



My pin counting starts at the top left corner and continues tor right.

See the pins function below:

Read more...
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