We had some breakthroughs with BLDC motor drive control last week. I’ll try to summarize it here as much for my own records as for anyone else. So feel free to skip if you aren’t interested. But if you are, please read on. In particular, I came up with a very easy way to figure…
Solar powered pump controller upgraded
Almost exactly a year ago, the prototype for the solar powered pump controller was installed and working. It was a hand wired and soldered on a perf board but it worked fairly well. But it is usually good to switch to printed circuit boards (PCBs) once the design has stabilized. We actually printed these a…
BLDC motor drive circuit success!
I got the chance to test the BLDC driver circuit that we finished recently, and after minimal fixes to the commutation code in the microcontroller, it works! I’m pretty excited about this. 🙂 Here is the setup we used: The 12V car battery at the top is supplying the power for the microcontroller which is…
Driving a BLDC motor
I’ve been wanting to experiment with brushless DC (BLDC) motors for some time now. Today, I finally got the chance to write the microcontroller firmware to do the logic. We are still waiting on some electronics to build the 3 half bridges needed to do the power side. But we pretty much finished the control…
Motion sensors don’t like acrylic/plexiglass
I thought the walkway lights were ready to install. On the test bench, everything worked fine. But every time we assembled the lights, the motion sensors stopped reacting to motion. For the past few days, we assumed something was getting screwed up in the sensitivity tuning of the PIR sensor. But pommm pondered on Monday…
Successful first test of “smart lights”
Having built up and tested the peer-to-peer RS485 network protocol, it was only a matter of coding for a few days to write up the firmware for these “smart lights”. Here is a quick video capture of an early test: The 3 lights on the desk are the top part of the lamp posts. They…
How fast is an AVR GPIO pin change?
A few months back, I saw this post from my friend Professor Montri Karnjanadecha regarding timing of an Arduino Nano pin. In it, he uses an oscilloscope to test what kind of speeds you can get from alternately pulling high/low a pin. But as he points out, he doesn’t get as much speed as he…
Very successful first peer-to-peer protocol test
I’ve coded up a simple test of the peer-to-peer protocol I’ve been discussing recently. Here is a picture of the set-up: For this test, I have 3 light posts transmitting short 10byte packets as fast as they possibly can given the constraints of the protocol. These constraints basically reduce to: You can’t send a packet…
Please stop interrupting me (more analysis of AVR interrupts)
I have recently been working on designing a peer-to-peer RS485 network protocol with collision avoidance (and maybe even collision detection) for the walkway lights on the land. (Link to last two posts: here and here.) As mentioned in my last post, even though each device is doing its best to detect if another device is…
Building a simple but efficient peer-to-peer RS485 network protocol
In my last post, I mentioned that I am working on a peer-to-peer network protocol for the RS485 network that I am using to communicate between my “smart walkway lights”. In today’s post, I will continue with a general outline of the approach I plan to take. This is all very nerdy, so if you…
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