Friday, June 29, 2012

AS5145 360 degree position sensor calibration

I got some samples of the AS5145 Automotive Rotary Encoder IC, and I did a quick test  for positioning of the motor using its PWM output signal thru a low pass filter to get analog out signal.

The absolute angle measurement provides instant indication of the magnet's angular position with a resolution of 0.0879° = 4096 positions per revolution.

It also has SPI (serial interface) as well Quadrature A/B (10 or 12 bit) and Index output signal, that will test and present in future video.

Wednesday, June 27, 2012

SS490 ratiometric hall effect sensors calibration

A quick demonstration of the calibration procedure of a SS490 ratiometric hall effect position sensor. It shows how to limit the range of the readings of the sensor on the AMC1.6 board (same applies to AMC644USB)

The SS490 ratiometric hall effect sensors are a nice contactless solution for position feedback that needs only two magnets to read accurately angles of 0 to 180 degrees. This can replace potentiometers that are normally not designed for too much motion because of the friction and have generally limited life cycle.


Sunday, June 24, 2012

AMC644USB Firmware 1.2d update

Here is a small video explaining the new changes / additions in the latest firmware 1.2d.

Some of the features now are:

1. Changed refresh of the LCD to only mandatory value changes and now doesn't leave any trails from other menu screens.

2. Added realtime change of PWM resolution between 9-bit and 10-bit (10-bit and 11-bit accordingly in bi-directional driving).

3. Added motor drive method selection that can be changed realtime:
 a. Bi-directional with digital controls (PWM=speed / D1=direction1 / D2=direction2).
 b. Uni-directional with combined direction control into signal (PWM: 0v=direction1 / 2.5v=center-stop / 5v=direction2)
 c. Scaled PWM output, from the 16-bit value (65535) into the PWM output  10-bit or 11-bit (1024 or 2048 accordingly) with no PID drive just for testing outputs range.

4. Realtime change between Quadrature encoders and analog potentiometers for position feedback with the flip of DIP switch2.

Tuesday, June 19, 2012

KP limits testing realtime

I was doing some changes on the firmware and decided to push the limit on the positioning. I increased the Proportional term in real time while swinging between two positions to see how high it can be before the motor starts oscillate! Here is the results:

Just keep in mind that for motion simulation you will never need KP higher than 25, after that, the motion gets too sharp and destroys any motion cues.


Thursday, June 14, 2012

Firmware 1.2b for the AMC644USB

Hi, I completed a re-shape of the firmware and fixed some bugs. Now the LCD doesn't leave artefacts from other menus, and I fixed a small math error in the PID routine.

Here are some videos, from testing it with pontentiometers and Quadrature optical encoders.

 Potentiometer test

Quadrature Encoder


Monday, June 4, 2012

Black or White?

I just wanted to share this photo, Black and White, 16-bit and 8-bit ...

Friday, June 1, 2012

Firmware update!!

Thanks so much for the interest into this project. I received lots of emails about it.

As the AMC644USB project is evolving new firmware updates will be posted, with the latest pinned on the side of this page.

AMC644USB_Fimware_1.2 (1-Jun-2012)
The zip file contains both Analog feedback sensors and Digital quadrature encoders feedback firmwares.

And here is a guide for the update procedure:
New firmware update GUI README.pdf

Just to clarify that you cannot use this firmware to any other board except AMC644USB v2.2, as it needs the bootloader part that is installed by me to each of the boards. The firmware files are all protected by powerful AES512 encryption and the program it contains, is decrypted on microcontroller's memory each time it is booting. There is nothing that can be read back from the chip, in fact if you try to connect it to any classic AVR programmer the bootloader will erase itself and the board will render useless.

Any special requests or customization on the firmware you should contact me: