Milp's tech stuff: tiny RV project, cat stuff, tinkerings

[milp]

I thought id make a blog-ish thing here about my daily tinkerings, since i often get told that it is rather interesting. However i must warn you that i do not really care for looks - to me it is all about function.

I’m in my thirties now and started as car mechanic (mainly fiat of course), then did some years as webdev and linux admin and finally got the chance to become embedded developer, building and supporting bootloaders. Finally going back to the realms of C, far from the weirdness of web development and consulting.

My car often gets me a lot of hate, so i might remove this again if people get too offended.

Currently i’m in the process of preparing my tiny RV '95 Fiat Cinquecento for 1 week of camping/party out in nature, together with my cat didi. For this i installed a tiny AC unit that is able to run off of the battery array, upgraded the solar panels to 200Wp, which creates more shadow for the actual roof and can provide up to 50% of the running consumption of the AC. Currently it is limited to around 165Wp by the small MPP Charging regulator.

I lovingly call it the

It runs two separate on-board intel atom platforms, one for infotainment and one primarily for (pre OBD) engine diagnostics. Since this car has a great community in europe, there is even an open source implementation of a full engine diagnostics suite for it’s ECU:

http://iaw-scan2.sourceforge.net/?p=download

Interior is subject to change, but here you see the infotainment unit and cb radio. Also included is my trusty companion Didi. He’s a deaf cat i rescued from a shelter about two years ago that loves travelling with me, camping and generally accompanies me almost everywhere i go.

There is a foldover bed instead of a passenger seat, the head-end box also serves as kitchen-storage and compartment for the secondary batteries and general electronics addons.

The ugly white stuff on the outside is epdm foam which is supposed to help with keeping the sun-heat out for AC-efficiencies sake. The interior walls are also insulated and all hollow sections of the body have first been glaced in underbody wax and then filled with packaging foams. There is also an independent heater that rtuns on gasoline and electricity. The interior fan regulation has been converted to use an efficient step down converter for airflow regulation instead of silly heat resistors.

Let’s see if i’m actually able to keep a blog and if anyone is even interested.

Here’s some bonus footage of didi eating his veggies:

https://www.youtube.com/watch?v=caE5kM3wO0g

[FaunCB]

lol I’m doing that to my van soon.

[anon86748826]

I approve of your car. It looks like a proper hackers car. Give your cat a few pets from me, he looks awesome! I am awaiting updates!

[Razor_Blade]

It is a neat project. I find mobile solutions for power, entertainment, and living interesting.

[ulzeraj]

@milp

My car often gets me a lot of hate, so i might remove this again if people get too offended.

As a Lada Niva and Fiat 147 fan from the other side of the pond I say your car is glorious.

[GigaBusterEXE]

I’d like to know more about your solar setup

[milp]

Will do soon! Thanks for all the supportive feedback

Currently however i’m in the process of trying to install some new fancy brake hoses:

However considering the old ones have been in for more than 25 years, i thought i’d get the proper tool too:

But even the most expensive tool does not save you from rounded nuts. So now i’ve got that brake hose hanging off the rear axle upwards with no way for me to grip it.

I guess i’ll have to drop the rear axle and gas tank after all

(notice how that is a cinquecento seat at my desk :D)

Here is a tiny bonus video showing a prototype nixie-tube based rev counter i made a few years ago. Also in the vid is Erich (RIP, my dear old friend)

As an interesting sidenote: on this car you can actually trigger any interrupt that just goes to the GND pin of the fuel pump relay, because the ECU modulates the rev signal onto the GND of the vehicle at this point. So feeding a rev counter is really easy.

[milp]

The new futon bed thing arrived today, i couldn’t resist trying it out:

[milp]

As promised, lets get going with the solar setup:

Those are two 100Wp panels that output around 22-24 volts, connected in parallel to 2 x 6mm² copper wire which leads into the wooden box that replaces the passenger seat in the front of the car. I used a Votronic MPPT charging regulator:

It also has a small solar computer kind of thing above the drivers place that provides stats, but sadly i do not have a picture of it.

The regulator feeds into the secondary battery bank, which is composed of 8 LiFePo4 12Ah batteries, each with their own BMS. Parallel to those there is still a chunky 100Ah lead-acid battery, as a kind of deep-temperatures-backup. A small 10-A fused wire also goes to the on-board-electronics system to keep the starter battery topped off.
Since the starter battery has it’s own relay to completely switch off GND connection at any time (fire prevention), it also features a small standby line for things like remote central locking to still work.

’

Some of the LiFePo4 batteries.

The lead acid battery which is infront of my ramen noodle stash (which also contains more batteries)

There is also a 80A relay to connect this system to the on board power systems and of course a small 300W non-sinewave inverter that has served me very well with powering either laptops or even power tools that go way above it’s rating.

The whole battery setup is (as you can partially see) normally covered with a carpet-thing, since this box also serves as the storage for all the kitchen and cooking supplies.

[anon86748826]

This might be a specific question, but how tall, or better how long, can one be to sleep in this car?

[milp]

The futon measures 200cm x 80cm and lies exactly flat front to back

[milp]

Does anyone else like to re-use broken flatscreens as workshop lighting?

And yes, this is also my kitchen.

[Trooper_ish]

the DIYperks guy does too

Turning Smashed TVs into Realistic Artificial Daylight

[milp]

This is awesome, i would however be way too lazy to use an external inverter as he did - most of the times the on board stuff suffices for lighting.

[milp]

Also here is something from the category of “if it’s stupid but it works, it ain’t stupid”:

My awesome 12v water cooker

[milp]

This forum def. feels more like home for my car project than our german community - i don’t get why people still judge every fking thing by looks

[Trooper_ish]

@milp

if it works, it ain’t stupid

True…

[Razor_Blade]

@milp

i don’t get why people still judge every fking thing by looks

They’re just jealous.

[Trooper_ish]

Function over Form.

Let Apple sacrifice effectiveness for the “pretty” aesthetics…

[FaunCB]

No but I do now o. O