Very small TQFP Atmega 328 breakout board ?

Robin2:
In the UK HobbyComponents supplies the tiny-lily board. Interestingly there is also a tinylily motor driver that is only 10mm diameter that has a DRV8837 h-bridge.

That motor driver can only supply 11V @ 0.85A. Is that enough for your loco's motor?

CrossRoads:
15.4mm a good width? With NRF24L01+ socket, and Reset, Tx, Rx, Mosi, Miso and SCK, a couple of PWM pins, one analog pin and one other digital pin. Plus Vcc and GND.

Thanks @CrossRoads, that should be as good as I'm likely to find.

Is this a design you have put together specially? If so, very many thanks.

I presume the idea would be to get someone to make the boards and for me to add the components.
How would I go about getting a few boards made, and have you any idea how much they would cost?

Again, many thanks.

...R

Henry_Best:
That motor driver can only supply 11V @ 0.85A. Is that enough for your loco's motor?

I don't know where the 0.85 amps comes from. The TI website says 1.8 amps.

In any case the MOST I have so far measured with a DMM is about 0.5 amps driving 2 OO Gauge locos on the same track. Driving one loco pushing another with wheels locked required about 200 mA.

I am using the dual version DRV8833 at the moment. I chose it because it works at low voltage - a single LiPo cell. You can parallel the outputs on the dual version.

They seem to be bullet proof - no problem crow-barring the rails. And they work without external components.

...R

I'll send the files (next week, see my PM), you can buy a 10-lot from iteadstudio for $9.90 plus shipping.
The nrf24l01 module hangs below the board. If you want it to overlap the board, that could probably be done as well, but the antenna would receive interference from wiring and not perform as well I would think.

As I said in my PM, there is no hurry with further follow-up. Let me know when you are in a position to discuss this further.

Just to avoid unnecessary activity, I think I would wish the nRF24 to overlap the PCB. But we can discuss that when it is convenient for you.

...R