An ATTiny Bluetooth Board

Since just about everyone who would be interested in electronics has a decent cellphone now, there’s an idea that we don’t need USB or weird serial adapters anymore. Bluetooth LE is good enough for short-range communication, and there are a ton of boards and Kickstarter projects out there that are ready to fill the need.

[Michah] has built what is probably the lowest-spec and cheapest BTLE board we’ve ever seen. It’s really just an ATTiny85 – a favorite of the crowd that’s just slightly above Arduino level – and an HM-10 Bluetooth 4.0 Low Energy module.

This board was developed as a means to connect sensors for a vintage motorcycle to an iOS device for display and data logging. A small, cheap board was needed that could be powered by a LiPo battery, and [Micah] created a board that fit his needs perfectly.

Four of the six IO pins on the ‘Tiny85 are broken out on a pin header; two are used to communicate with the BTLE module. It’s simple, fairly cheap, and can be powered by a battery. Exactly what you need if you want a wireless sensor board. All the files can be found in the Git repo and everything is open source. Not bad.

26 thoughts on “An ATTiny Bluetooth Board

  1. I messaged the designer to see how his range is. Since the antenna is parallel to the PCB. I am using the HM-10 and HM-11 and I have the Antenna off the side of the PCB. There was a instructable about issues with range and the PCB but might be due to ground plain.

    1. I have not done any real empirical testing and was worried about the USB power crossing the antenna. But I haven’t noticed any degradation of range. Though my applications are all relatively close range, just a couple of meters max, so your mileage may vary. FYI: with the HM-10 you can bump the antenna power, I have my personal projects set pretty low to conserver battery life…

    1. Be warned these don’t have standard 2.54mm headers so you need a custom PCB or some non standard cables to break it out.

      Also not managed to program mine, tried using the programmer built into the STM and Gecko dev boards but they wouldn’t communicate!

    1. Seriously. What is that even supposed to mean? The tiny85 has a fully-featured AVR core, it just doesn’t have as many integrated peripherals or as much memory as the larger chips.

        1. OMG I was just about to say that. Last post I made that was slightly negative about Benchoff got deleted. How did yours make it though? By the way the ATtiny 85 is compatible with the Arduino IDE.

    1. I got a lot of inspiration from that project. The biggest differences with this project is there is a USB power and charging circuit (using a MAX1555) , LiPo JST PH connector (for a battery), and the ATTiny85 is a DIP package instead of SMD (for easier hacking).

      1. Did you ever think you should have given proper credit to Ladvein then? Open Source? Screw that right? Sad. Sad. Sad. Reading about and borrowing ideas from others is how I learn too, but I’m sure to credit them when credit is due. You sir can sod right off.

        1. Wow! Internet is cruel! I was well into my project well before ever running across Ladvein’s project. His project just confirmed a lot of my design decisions. Ladvein is super awesome, but I don’t think feel I need to explicitly credit every website I had come across.

          1. Yea, funny thing… one minute you were heavily inspired by it the next you were just passing through and ran across it. Why credit anyone ever, right? Especially super awesome people you learned from.

        2. it’s just a BLE module connected to an AVR. these things have been done before. it’s not like either invented something brand new and novel and patentable. the “story” here is the level of documentation and simplicity. Ladvein’s board looks like it would be harder to use, since you’d have to move solder blobs to reprogram it. Michah’s design is cleaner, and not really inspired by Ladvein’s from the looks of it.

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