Gate Valve Drive Electronics

[TerryJC]

I can make up a cable using the jumpers that I already have, As far as the dongle is concerned, I don't have the micro USB to USB Adaptors yet, but I should be able to sort that with a different type that I have in my workshop.

I'll see you tomorrow.

[TerryJC]

Penri,

I've just checked my stock and I only seem to have two 10 k resistors left (I lost three when I brought the kit in last week). Do you have an odd one? If not, I'll use 8.2 or 12 k, but it would be nice to keep them all the same.

[Penri]

What do you need, 1/4 W I have 1/2 W I may have?

[TerryJC]

I've been using 1/4 W. I'll use a different value if you only have 1/2 W, because I won't be able to get a 1/2 W resistor into the heat shrink. It's not critical.

[Penri]

I'll bring some 1/4 W 10k's with me tomorrow.

[TerryJC]

I only need one.

[TerryJC]

I've attempted to assemble the device, taking account of all things that that will need to be connected, including during maintenance / diagnostics. At the moment it's looking pretty difficult. See the series of images below:

Gate_Valve_as_Intended.jpg (274.79 KiB) Viewed 1307 times

As you can see the Monitor HDMI Adaptor fouls the pipe and there is limited room for the USB connector. To achieve even that I had to put the Pi onto long pillars. I tried reversing the Pi:

Gate_Valve_Pi_Reversed.jpg (283.04 KiB) Viewed 1307 times

and

Gate_Valve_Pi_Reversed(2).jpg (279.97 KiB) Viewed 1307 times

That's a lot better, it's a more natural route for the power for the Pi and there is only slight fouling of the HDMI Adaptor on the Actuator. It does put the Pi under some strain though.

Finally, I wondered about mounting the Pi sideways (and still on a tall pillar:

Gate_Valve_Pi_Rotated.jpg (265.88 KiB) Viewed 1307 times

This works pretty well, but will need a fair bit of rework on the positions of the other devices.

Any ideas?

[Penri]

Terry

I can definitely appreciate the problem from the photos, those connectors to the RPi are enormous compared to everything else.

How would the dongle work with the side mounted RPi, as shown in the last photo?

The only thing I can suggest (which you might for tried of course) is to move the RPi to the "top" of the base board, just below the actuator, still on tall standoffs and shift everything else, bar the Vero board, down.

Alternatively we just make the base board bigger!


Penri

[TerryJC]

Penri,

I haven't tried moving the Pi to the top; that would certainly work from the point of view of the Ethernet dongle and the HDMI Adaptor. The thing I have to watch out for is that there is enough room for the jumper lead connections if they end up underneath the Pi (or it's connectors/adaptors. I'll definitely have to shift the other components around, whatever configuration we end up with.

I'll give it another go tomorrow and keep you posted.

[TerryJC]

Penri,

I have good news and bad news.

First the good news:

1. It looks as if the re-arrangement of the modules on the base board can be made to work. If I put the Pi at the top with the GPIO pins uppermost, the Motor Drive Board on the right, the DC-DC Converter on the left and the A/D in the middle, then I have plenty of room for the various leads and adaptors to be fitted without fouling the Actuator or the pipe.

Now the bad news:

1. The DC-DC converters that I had selected seem to suffer from the same poor regulation issue as the ones that you bought at the beginning: see viewtopic.php?f=15&t=18&start=10. I applied 12 V to the input and set the O/P to 5 V (off load) and when I applied a 10 Ohm Load, the voltage dropped by over half a volt. I thought about whether we could set the voltage on the basis that we knew what the load was to be but dismissed that because any fault could result in an over-voltage to the Pi. I still have 4 of the other type of converter that I used for Sump and Butts Pis, so I'm going to make up a filtering circuits with capacitors as I did for the existing Pis:

Converter.png (30.96 KiB) Viewed 1303 times

I've ordered a batch of these converters and will use the others for less critical requirements.

2. The Micro USB to USB Adaptors arrived today and they don't fit! The product is fine in itself, but the body of the adaptor is about 1 mm too wide, so they foul the power connector, which is adjacent on the Pi. I have a number of standard Micro USB to short lead to USB Adaptors from earlier purchases of Pi Zeros and freebies from MagPi Magazine, so we won't have to wait for replacements. In the meantime, I've ordered some more from Gearbest. The replacements were pretty cheap at pennies each, so it's not the end of the world.

Onwards and upwards!