rolling my own 70 series auxiliary gauge pod (1 Viewer)

[John Young]

I mentioned in a couple of other threads my frustration with the OEM gauges and my desire to at least add oil pressure and temperature and a hobbs meter. It would be nice to measure a couple of other things accurately, like coolant temperature and and maybe fuel pressure too. With Biscuit, our model 77 I lashed together some inexpensive gauges from Amazon and put them in a kind of ugly enclosure on the dash before we took it across the US. I was pressed for time and it worked but it was esthetically .... unpleasing.

One of the 70 series with me here in Dubai has the 2nd fuel tank switch/meter pod and the other does not. Ideally I've wanted to re-purpose the OEM pod to include more meters. Today up in Sharjah I picked up one complete pod and two covers.

I paid too much for them, but I also got a very good price for a couple of really nice aluminum running boards for the HZJ81 project, so it all evens out.

I think the best thing is to try to use the OEM white plastic body. The open space is 194 mm long by 62 mm high if you remove the gas gauge and about 115 mm by 62 mm if you leave the gas gauge in place.

But more likely it is only 60 mm high if you take into account the space taken by the screw holes.

So that's the space I'm planning to try to put something interesting into.

 

[John Young]

Turning now to the general approach to the display portion that I'm going to try, at least initially...

My younger boy is fiddling with arduino micro systems on a chip. They each cost 20 buck or so, they have 6 analog inputs and a bunch of digital IO pins that can easily drive a little display. I'd like to have some flexibility in creating the look of the display so that suggests a display that has integral lighting.

From hunting around on Amazon it seems that a 3.5 TFT LCD display is about as big as I can go if it is to fit inside the white plastic enclosure. This one looks promising:

Here's the dimensions.

It does have a backlight. Just not sure about the direct sun as it is an inexpensive display at less that 20 bucks. I'd prefer an e-ink display with backlight, but I can't seem to find one of those.

 

[JuanJ]

Hello,

This looks promising. And much more practical than analog gauges squeezed into such a small space.

Keep us posted on your progress.





Juan

 

[Gengis]

Check out these guys XTreme EFIS/EMS . they are avaition guages, but they make damm fine auto gauges, chech out the single gauges as well.

G

 

[John Young]

Check out these guys XTreme EFIS/EMS . they are avaition guages, but they make damm fine auto gauges, chech out the single gauges as well.

You are right, of course. Aircraft panels would be the best. I just can't quite justify the hefty price. They do put a lot of engineering into the displays and making them readable in bright sunlight. This is an issue I've been giving some thought to. I'm starting to think that a wide angle white on black character LCD panel would be more usable (readable) in practice.

 

[divemedic]

Following

 

[John Young]

This is really a very interesting thing to ponder--there are so many trade offs. I've been looking at e-ink displays because they are great for daylight. The downside is that they tend to be very slow on the update, which really does not matter other than for RPM (Golden Boy is missing a tach).
The 2.13 inch three color model is 23 USD and is 65mm by 30mm, which means I could fit three of them side by side.

Then there is a really old-school but pretty nice genset monitor that I could modify for use.

This is between 50 and 100 bucks without the sensors. It has the advantage of being really straightforward. It is 10cm by 10cm.

Then I went down the rabbit hole of wondering if I shouldn't get a more robust data collection device. Something like this:

Then I got to be thinking that if I could use a bluetooth data monitor I could repurpose an android phone which has the advantage of having adaptive backlighting. I have not found any multi-channel bluetooth data acquisition modules just yet. Still looking.

The dollars a low enough that I might try a couple and see which works best.

 

[tmarx]

Check out these guys XTreme EFIS/EMS . they are avaition guages, but they make damm fine auto gauges, chech out the single gauges as well.

G

That is what I fitted ...

 

[John Young]

That is what I fitted ...

Looks nice, Tmark. And very practical. I've been searching online and I am leaning towards trying something like this:

run with a raspberry pi B+. This is a 6.86" display with an HDMI interface that will fit within the dimenions of the OEM pod with a little modification. I'm trying to pick something that is fairly common so that if it works others could give it a try and improve.

 

[John Young]

The more I get into this, the more options there are. I've gone ahead and ordered 3 of the displays pictured above, with touch screens and an HDMI interface. It's pretty nice in that it will be possible to have it serve as camera monitor as well as gauge cluster. Total cost for 3 units was 216 USD or 72 USD each. Interestingly the cost for the panel itself was only 24 bucks. It was the HDMI converter that was the majority of the expense. I'm looking for simplicity of implementation so that's why I'm going HDMI.

I attach the technical drawing and the spec sheet for the panel in case anyone wants to look through that.

 

[divemedic]

Any plans to reproduce and sell, I know at least 1 dude who would be interested.

 

[John Young]

Any plans to reproduce and sell, I know at least 1 dude who would be interested.

Hi DM, that's very flattering but I'm not really set up for that. I'm hoping that if successful others can do that. Software will be the key here I think. These displays are very interesting. The one that fits in the OEM 2nd tank pod is just right for 70 series. But there are a bunch more, wider displays, that might be more appropriate for 80 and 100 series. They would need pods that would look good in those vehicles.

So, in sum, this is kind of an experiment. I'm starting with the 70 series because I have a real need to do something for Golden Boy and the Troopy.

I've also been thinking about some of the practicalities. I don't really want to run a bunch of analog lines from the engine bay to the dash. I did that with Biscuit and it ended up that the motor from the AC affected the oil pressure measurements on the inexpensive Amazon digital oil pressure meter (because I was forced to use the wrong kind of wire, I'm pretty sure.) I'm accordingly leaning towards a remote A/D converter that connects to the raspberry pi via a single USB cable. These are not high speed signals. You also get a degree of isolation and protection for the computer by doing it that way.

 

[saltycoconuts]

Hi DM, that's very flattering but I'm not really set up for that. I'm hoping that if successful others can do that. Software will be the key here I think. These displays are very interesting. The one that fits in the OEM 2nd tank pod is just right for 70 series. But there are a bunch more, wider displays, that might be more appropriate for 80 and 100 series. They would need pods that would look good in those vehicles.

So, in sum, this is kind of an experiment. I'm starting with the 70 series because I have a real need to do something for Golden Boy and the Troopy.

I've also been thinking about some of the practicalities. I don't really want to run a bunch of analog lines from the engine bay to the dash. I did that with Biscuit and it ended up that the motor from the AC affected the oil pressure measurements on the inexpensive Amazon digital oil pressure meter (because I was forced to use the wrong kind of wire, I'm pretty sure.) I'm accordingly leaning towards a remote A/D converter that connects to the raspberry pi via a single USB cable. These are not high speed signals. You also get a degree of isolation and protection for the computer by doing it that way.

Are you leaning more towards raspberry pi over arduino?

 

[John Young]

Are you leaning more towards raspberry pi over arduino?

I started thinking I was going to use arduinos, but then when I looked at the challenge of driving a nice display I came to the conclusion it would be much easier to do it with a current Raspberry Pi version 4 B. It even will drive two HDMI's directly. It is way overkill, but I think it is the right decision.

One thing about arduinos is that they have analog inputs on them already. Raspberry Pi's don't. But as mentioned above I think it will be better to do the data acquisition remotely and take it to the CPU via USB. In short the Raspberry should be much more flexible. I've ordered the Pi and will start fiddling with it tomorrow.

 

[saltycoconuts]

I started thinking I was going to use arduinos, but then when I looked at the challenge of driving a nice display I came to the conclusion it would be much easier to do it with a current Raspberry Pi version 4 B. It even will drive two HDMI's directly. It is way overkill, but I think it is the right decision.

One thing about arduinos is that they have analog inputs on them already. Raspberry Pi's don't. But as mentioned above I think it will be better to do the data acquisition remotely and take it to the CPU via USB. In short the Raspberry should be much more flexible. I've ordered the Pi and will start fiddling with it tomorrow.

Keep me posted. That’s been my delay is the location of everything; coding is done and I can start installing sensors but I’m just not content with where the screen will end up. I think I’ve narrowed it down to this slot in the gauge cluster but I want to get a spare cluster to dissect before I ruin mine lol

 

[John Young]

The long, narrow displays for the above the dash pod arrived from China yesterday. They look pretty nice.

At this point I've got more than a dozen different items that hopefully will all go into this experiment. Lots of little items too, like a stable power supply to provide the bias for the temperature and pressure sensors and a decent keyboard and mouse to program the Raspberry Pi with, connectors and so on. I'm headed back to Dubai in a couple of days with all my booty and then it will be time to start (1) piecing the hardware together and (2) figuring out how to program the meters I want to show. Ideally the Pi would also run Android Auto at the same time (lots of people have don this). It's been a while since I last did some programming but I was working with my younger son on his Python programming homework and plainly there is a lot of support for DIY programming out there.

 

[John Young]

Keep me posted. That’s been my delay is the location of everything; coding is done and I can start installing sensors but I’m just not content with where the screen will end up. I think I’ve narrowed it down to this slot in the gauge cluster but I want to get a spare cluster to dissect before I ruin mine lol

That is an interesting idea SC. I had not considered sticking a display actually in the existing instrument cluster. But now that you say it there are plenty of appropriately sized displays that would work nicely in there.

 

[CRSWA]

This kit looks promising. Also sized to fit in the gauge pod. Programmable to display oil temp, egt, boost, coolant temp, AFR, etc. It's put out by Reveltronics. Does anyone have any experience with these?

 

[John Young]

This kit looks promising. Also sized to fit in the gauge pod. Programmable to display oil temp, egt, boost, coolant temp, AFR, etc. It's put out by Reveltronics. Does anyone have any experience with these?

I saw that CR and at 168 USD before adding the sensors it seemed like a lot at the time, but now that I'm adding everything up I'm getting into multiples of it. I think it may be a very good choice. I'm going to keep it in mind.

 

[Gengis]

fitted

Where is the pod from Theo. Also, is that a JVC radio below. I love and hate mine. Good sound a bitch to program

G