Avoid a panic half way round the track
While coming to the end of a running session of my 5″ loco at the club raised level track I suddenly realised the axle pump was not making its normal rattling noise. Water level was likely very low and there appeared very little in the glass sight gauge. My state of panic endured until I reached the filler hose.
On returning home to the workshop I resolved to try to make this alarm situation more readily visible. The common solution is to add a second sight glass feeding from the water tank and visible in the ‘cab’. My engine did not have a great deal of room for this addition.
Sacrilegiously I began to consider an electronic solution which probably wouldn’t make me popular with the mechanical diehards but the challenge appealed.
The electronic solution turned out to be a multi faceted activity. An initial bird’s nest lash up was followed by a PCB designed in Fusion 360 Electrical. The PCB was milled on my vacuum table fitted to the Tormach 440 with the Gerber and Epsilon files converted to GCode using FlatCAM. Having completed the PCB board this led to a customised enclosure designed in Fusion 360 and 3D printed in the Qidi X Smart 3.
The circuit is a NPN transistor that is turned on by water conduction between two sensor probes which in turn drives a second NPN to illuminate a flashing LED. The module is powered by a CR2025 button cell.
The enclosure consists of three parts, the base, a snap on lid and a round boss that matches the diameter of the water filling hole on the engine side tank. The two water sensing probes are made from 16 swg wire protruding from the boss.
The round boss is held in place with a M2.5 countersink screw and could be dimensioned to suit different sized filler holes. Having it as a separately printed item is also useful in that it allows the enclosure base to be 3D printed without support.
Here is are some views of the completed assembly.
It seems to work quite well and is surprising sensitive down to the last few millimetres of the probe rods. Time will tell.
If you want more details then please send me a message.
Links to similar or related post are listed below : –
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- Setting up the timing on a Polly V locomotive
- Halloween Steaming of the Polly
- Rosebud Grate further tests
- Fitting and Fixing the Rosebud Grate in the Polly V
- Rosebud Grate CAM and manufacture on Tormach PCNC440
- Rosebud Grates for Live Steam Locomotives
