Posted in February 2015

MCPWM with LPC175x/176x

MCPWM with LPC175x/176x

For my new “mini Sumo” size robotic platform I am using MCPWM to control the DC brush micro-motors instead of PWM as I am keeping the PWM outputs in case I will want to control some sensors or servos. I could not find a functional example on how to control DC brush motors using a … Continue reading

Breaking the record

Ok, is official: streaming at 14 FPS over a serial link. True, is only B&W and 160 x 120 but is still a record, a personal one. I am trying to get 10 FPS on a 460,800 bps line or even better: 230,400 bps! Then I can stream images over a wifi/bluetooth link. Update: Already come … Continue reading

Side by side tests

Side by side tests

A side by side test: 320 x 240 pixels, B&W, 8 bits/pixel (76802 Bytes) 320 x 240 pixels, B&W, 4 bits/pixel (38402 Bytes) 320 x 240 pixels, B&W, 8 bits/pixel with RLE compression (25981 Bytes) 320 x 240 pixels, B&W, 8 bits/pixel with RLE compression – aggressive (17924 Bytes) Last one was done using some aggressive settings on … Continue reading

A simple RLE implementation (cont)

A simple RLE implementation (cont)

  I managed to get the RLE implementation working quite well. The original code is adding an index information for EVERY pixel, which on a noisy image can double the size of the image instead of compressing it. This is pretty much a functional version: … for (i = 1; i< lineLen; i++){ if (seq == … Continue reading

A simple RLE implementation

I was explaining in the previous post about the RLE algorithm (Run-Length Encoding) I am using as an alternative to jpeg compression. The good part about this is that will work with OV7670/OV7725 and will not require a lot of CPU cycles. The code looks something like this: // Capture and stream a frame in B&W … Continue reading

“Home made” compression

“Home made” compression

I am not sure what am I doing wrong, but for now I can not get the OV2640 camera to create a proper jpeg file. Sometime works, sometime not… Plus, the OV2640 is very expensive, changing from raw to jpeg is slow as I need to load a different set of registries, etc. So I … Continue reading