Can someone advise wire labels  - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: August 25, 2020, 09:36:21 pm
content: I'm trying to fix a Horizon treadmill, its main controller board is connected with motor board by a 8 pin wire, as main board has some issue, i want to hack main board and replace it with Arduino. I want to understand communication between motor board and main board so that i can send motor board instructions to run the motor.Attached are the images of main board and motor board, I want to know what are these labels on main board, Power, GND are main power board, SAFE looks like are for later use?? DA, and DB are some communication wires, looks like its I2C ?

author: bob91343
author_rank: Super Contributor
timestamp: August 26, 2020, 03:24:15 am
content: I don't see any labels.

author: ledtester
author_rank: Super Contributor
timestamp: August 26, 2020, 04:59:53 am
content: QuoteThe labels can mean anything the designer wants them to mean.QuoteAre those pins connected to anything?QuoteStandard approach is to first interrogate the signals using an oscilloscope. If DA and DB look like digital signals then try to discern how they work using the scope traces or attach a logic analyzer. A logic analyzer will allow you to capture a lot more data than the scope.If the 8-pin connector goes to the "dashboard" it probably is just an interface to read the buttons and display information. Look at what chips are present on the dashboard and that might give you some clue as to what the DA/DB protocol is. Reverse engineer the dashboard and you'll be in a much better position to fake it out.

author: sairfan1
author_rank: Frequent Contributor
timestamp: August 26, 2020, 06:36:08 am
content: I checked there is MAX3085 at both ends, that means its using RS485 to communicate.As its not working, what kind of signal i should expect, based on protocol is there some way i can hack it, like using arduino send command to start motor etc.

author: ledtester
author_rank: Super Contributor
timestamp: August 26, 2020, 01:09:36 pm
content: If the dashboard isn't working then you're probably out of luck.The idea would be to monitor the RS485 communications between a working dashboard and controller board to see what messages are sent when certain keys are pressed. Then you could design a replacement to mimic the same messages.Even with a working dashboard it could be difficult or even impossible to reverse engineer the communications protocol. The internal layout of the messages may not be obvious. It may require responding to messages from the controller board rather than just sending them. There might be a checksum algorithm involved. The messages might even be encrypted.

author: sairfan1
author_rank: Frequent Contributor
timestamp: August 26, 2020, 04:02:22 pm
content: Can i bypass all and run the motor, like it has MCU on main board and motor board, I remove the main board, now on the motor board i find the points where MCU of motor board sends PWM signal to the motor, at this point i generate PWN from an Arduino board and run the motor.Please refer to attached image treadmillside.jpg and MCU datasheet

author: ledtester
author_rank: Super Contributor
timestamp: August 27, 2020, 02:48:24 am
content: Sure, if you can reverse engineer the motor board.

author: ledtester
author_rank: Super Contributor
timestamp: August 27, 2020, 02:55:19 am
content: You might find it easier to connect your own motor control board (one that your either build or buy) to the motor -- then you'll know exactly what signals to send to the control board.