More ATtiny experiments…

Since I managed to breathe life into my ATtiny-based speaker delay project I’ve been working on more ATtiny-based boards. There are many potential applications I can see (if I look hard enough…) for a small SW-based controller and that is what I’ve tried to build. The hardware was done a while ago, but the software was lagging (and still is somewhat).

I also received my TinyLoadr programmer a few weeks ago and it was definitely worth the wait. I’ve mounted the board to a piece of aluminium to keep it stable and now its more or less a perfect tool – very highly recommended if you want to play with ATtinys!!

To speed up my development cycle I’ve build a prototyping setup with a ZIF-socket and a solderless breadboard. I’m not a fan of solderless breadboards in general, but they do have their occasional uses and this would be one of them. I bought a few small ZIF-sockets from ebay and together with the tinyloadr programmer they make up an excellent prototyping platform. Swapping ICs from one ZIF to the other is still a bit of an annoyance, but it’s far more flexible than the alternative 🙂

If you need more memory space (or more I/O-pins) than the ATTinys can provide then I am also working on an update of my AmpDuino-concept. This will be a fully-fledged controller based on a stand-alone ATmega-chip that can do the same as the old version AmpDuino, but in a more optimised way. Connections etc. will be laid out for what I consider to be typical audio applications. ETA is, as always when there is software involved, unknown 😀

More Ampduino testing…

I am still making more tests with the prototype Ampduino board and everything still seems to be working OK. The only problem seems to be persistent issues either with the FTDI-drivers or the Nano board I am using – I have a couple of more Nanos on order though, hopefully that will help. Now, when I ordered the boards I ordered a few “extras” as well 😀

The first is a motor driver board based on the L293DD H-bridge driver. This (and the circuit) is nothing out of the ordinary – it is basically lifted straight from AMB’s implementation on the LCDuino-board, including the option for sensing the position of the pot using an analog input pin. What is a little out of the ordinary is that I made the board very small and included pads so it can be mounted directly to the back of an Alps motorised potentiometer. This seems to work well so far – the attached picture shows the board mounted to an Alps RK16816 for testing purposes.

The second extra is an I2C isolator board based on the Analog Devices ADuM1250. This chip can do isolation of an I2C-line and it supports both bidirectional communication and level-shifting (by means of different supply voltages for the two sides of the isolator). The board is tiny and can either be used inline or installed permanently on the Ampduino using an angled header that is soldered to the board. I haven’t put this together yet because I don’t really have an application for it until I start controlling DACs via I2C, but it looks very useful so thanks to Zwack at head-fi for the suggestion 🙂

Basically this means I now have the display functioning, an IR-receiver connected and working and the basic motor driver working – not bad I think 🙂 Further expansion of the Ampduino is also in the cards as I have a PGA2310-based volume control board in the works. Prototypes have been ordered and hopefully in a couple of weeks or so I can test that and see if the Ampduino can do SPI as well 😀

Ampduinos in the wild…

Now the AmpDuino project is starting to take shape 😀

I received the prototype boards yesterday and quickly assembled one to try it out. So far it has only been a very basic test with an I2C display and an IR-reoeiver and both seem to work without issues.

There are a couple of minor cosmetic issues with the boards and some of the connector placements might cause some problems later on (note the angled header for the SPI port – a straight one with a cable would probably block the USB port 😦 ) but so far it seems to be minor niggles only.

Programming-wise it also seems to be working well, apart from some annoying issues with the drivers for the FTDI USB-serial chip on my mac – they don’t seem to want to stay installed and working…

Next up is to do more testing on the AmpDuino itself and a few “bonus” boards I ordered as well, plus of course start building on the code base for the AmpDuino – stay tuned! 😀