General Stuff(tm)

[stephen_usher]

Another thought I had was to put a resistor in series with the capacitor with the same resistance as the ESR of the capacitor at 100Hz, effectively reducing the voltage across the capacitor by half, but I have no way of testing the ESR.

[stephen_usher]

Oh well. No post at work today (not a Royal Mail strike day is it?), so no wires. I can still make up a couple of the boards but without the wires to the pick-ups.

[stephen_usher]

It seems that I had the wires sent to home rather than work... they're here I can do stuff! :-)

[stephen_usher]

Well, the board works!

Put it all together and hooked it up to a loco motor and other bogie and was able to talk to it from the DCC controller.

IMG_2826.jpg

IMG_2827.jpg

The only problem is that the only spade connectors of the right size to fit the motor from RS are too long, stopping the power bogie from fitting into the body. :-/

IMG_2828.jpg

Still, it does work!

[stephen_usher]

Does anyone know where I might be able to get bare (no insulator) crimp 2.58mm spade connectors? Both RS and Farnell just have the long ferrule-type connector ones which are way too long for what I need.

[stephen_usher]

Managed to cut enough of the insulation off and bend the connector over enough to get the bogie to fit. A bit of a struggle though.

[stephen_usher]

Hmm... Bit of a problem. Somehow the motor is trying to pull 3A and the DCC chip is only rated for 1A. This is very strange given that when I powered this loco using a bench power supply it only ever drew up to 800mA!

[stephen_usher]

Hmm... I think that it must be the PCM "voltage" control from the control chip confusing the ammeter as the controller is saying a very much smaller amount of current is flowing than could possibly be 3A. Anyway, I'll put a 10R resistor in-line anyway for extra protection and it makes the motor control better. 27R is too high and I don't have anything in between.

[stephen_usher]

Here's the board in situ, with the teeny-tiny DCC decoder sitting it its socket.

IMG_2831.jpg

[rubber_jonnie]

Here's the board in situ, with the teeny-tiny DCC decoder sitting it its socket.


IMG_2831.jpg

Very neat :)