After several fails trying to disable autoreset with a resistor, I've finally managed to do it with a capacitor connected to reset and ground. Now, I'd like to be able to programmatically toggle this from a pin, so that I can send a command via serial which will disconnect the capacitor in preparation to upload new programming.
Could i do this with a transistor? My theory is to connect an Arduino pin to the Base, the Collector to reset and the Emitter to ground. The only thing is, I'm not entirely confident with the workings of transistors, and capacitors are a new one to me. Can anyone advise?
Well, the actual project is a fermentation controller which is sat in the garage. It communicates via a router to an external webpage so that I can monitor the temperatures, etc. For this bit, autoreset needs to be disabled otherwise it monkeys around with internal timers and flickers solid state relays.
However, I'm also programming the unit remotely when I need to update the software. To do this, I need first to turn autoreset off. I could do this by going out and removing the capacitor (or flicking a 'programme me' switch to disconnect it), but I'd like a programmatic solution (cos I'm lazy) - so some way of flicking the switch via an output pin would be ideal.
The router is plugged into the USB port of the router which has OpenWrt installed on it. From there, I can wget a new hex, and use AVRDude to write to the Arduino