AVR
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This is an UNOFFICIAL AVR community.
This is a community for people who use AVR microcontrollers. This can include Arduinos, Arduino clones, Arduino like boards, and stand alone AVR chips and self-designed boards.
NOTE: If your circuit is doing something weird when you touch a wire or move your hand across it see this pinned post.
This is a community for everyone who is interested in AVRs and Arduinos from beginners to experts, kids to adults, hobbyists to engineers.
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All Lemmy.ca rules apply here.
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Everyone (see rule 98) is welcome.
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If you’ve seen a question 100 times answer it the 101st time or ignore it. Even better, write a complete, detailed answer and suggest that the mod(s) pin it to the community.
[Did you actually think there were 98 rules?]
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If you present something as fact and are asked to provide proof or a source provide proof or a source. Proof must be from a reliable source. If you fail to provide proof or a source your post or comment may be removed.
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founded 1 year ago
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If your circuit is behaving weirdly, switching on when you touch a wire or move your hand over the circuit you almost certainly have a floating input. You can solve this problem with a pull-up resistor. Many AVRs have built-in pull-up resistors that you can turn on using code.
In Sketch:
pinMode(2, INPUT_PULLUP);
In BascomAVR:
Config Portb.1 = Input Set Portb.1
There's a great article at SparkFun about Pull-up Resistors.
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I bought a few of these years ago. They are a small board that plugs into the back of a standard 1602 LCD board. They come with an ATMEGA88 which I changed out for an ATMEGA328P. They have a 74HC595 and a MAX232 to drive the LCD and RS-232 respectively. The LCD interface is SPI and it pulls all of the ports out to standard ETTEAM 10-pin box headers.
I find this form factor amusing and have tinkered with it but have never used this for a project.
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I've still got a bunch of DIP-28 ATMEGA328P chips. I've had these in my bin since the days before the SMD version of the 328P was widely available. I've got around 50 of the SMD version now that I'm using. These DIP-28s are just sitting here until my son or one of his friends want them for a school project.
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Most of the projects I design start out on solderless breadboards. The one in the bottom of this picture is a ROM switcher and reset circuit for a Commodore 64 that I'm working on. This circuit will fit inside the footprint of a 27256 ROM chip in a 2364 to 27256 ROM adapter.
Other projects are larger like this early prototype of my maple syrup machine room controller, the SapMaster...
or this...something...that I was doing with an ESP32 and a Raspberry Pi Zero W.
Over the years I've collected a number of solderless breadboards. Some I bought myself and others came with kits that I bought. A number of them came from Hacker Boxes when I had a subscription before the pandemic. I had the delivered to a UPS store in Ogdensburg, NY and drove over and picked them up once a month. Hacker Boxes are cool. Definitely check them out.
Some of the solderless breadboards in my BREADBOARD drawer were cheap, Chinese knock-off breadboards. They had...issues...
not to mention the fact that the contacts were SUPER cheap. They often didn't line up well with the holes and prevented pins from being plugged in. Dupont wires and header strips were a BIG challenge and when plugging in a header strip the contacts often stretched and didn't spring back properly.
I finally decided that it was time to replace all my cheap breadboards with better ones.
The cheap ones can be bought on AliExpress for CAD$2. The better ones cost in the neighborhood of CAD$10. I spent some time doing research and talking to friends in the electronics business and settled on Global Specialties (pictured above.) Just about any of the brands available from Digikey or Mouser will be the same quality.
The contacts are nickel plated phosphor bronze and are rated for 1.5A at 36V.
I've switched my prototypes over to the new breadboards and am very happy with how the feel.
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This is the machine that runs my maple syrup machine room. The PLC (the large grey box on the left in the second section from the top) runs a MEGA2560 Pro Mini with an ESP32 as a WiFi modem. There are more than 4,000 lines of BascomAVR running on the MEGA2560 and around 800 lines of Sketch on the ESP32.
The top section is power distribution. The middle section is supposed to be PLC only but my 24V power supply and distribution leaked into the right hand end opposite the PLC. The bottom three sections from left to right are analog input, digital input, and digital output.
This thing runs a vacuum pump (a MasterCool 90066A), a transfer pump (a small Iwaki), an RO pump, and two solenoid valves (to be replaced with motorized ball valves this summer.) It takes inputs from a bunch of float switches, two vacuum transducers, a pressure transducer, three high precision digital thermometers, and two last time of flight sensors. This thing runs the entire process from the trees through collection and storage through the RO into secondary storage and out a tap to be boiled in the evaporator.
The PLC uses a pair of custom boards that I designed to fit in the BUD case they're installed in. I'll post pictures of the inside shortly.
