1202 ALARM

Bored today, so I decided to make up some remote temperature sensors. They're based on 18DS20 1-wire sensors which can be operated over just 2 wires in power parasitic mode where power is taken from the data line and held in a capacitor on the chip to allow it to make the temperature conversion. In this mode the VCC (positive) and GND (negative, ground) pins are wired together and then to ground.  The ends are made from old bits of Biro pens and pieces of heat shrink sleeve. For anyone who tinkers or 'makes' a good supply of heat shrink sleeve is essential and makes for very neat finishes. Good for car wiring too.

I put the caliper back on the car, bled it and pumped like mad and eventually the piston came loose. Back on the bench the problem turned out to be rust around the lip on the caliper casting where the piston fits. The piston had a little surface corrosion, but this cleaned off with wire wool and some 4000 grade wet-and-dry. I took a cone grinder fitted to my Minicraft drill to the lip on the casting and lo-and-behold the piston was sliding freely in and out again. The only problem was the replacement dirt gaiter which no amount of pressing and poking would convince to stay firmly down on the caliper. Investigation showed this to be due to more corrosion which I did my best to clean up. The caliper is now back on the car, bled and working as it should. It isn't perfect, but it will be fine while I scope eBay for a replacement.

The front nearside brake caliper has been sticking for a while.  It took a month to get a reconditioning kit from Renault, but taking the caliper off takes 5 minutes. Problem is getting the piston out. I've tried 3 different bodge methods to no avail, but putting the caliper back on the car and pumping the brakes came closest, so I'm going to try that again tomorrow. After that hopefully a good clean with fine wet & dry emery and fit the new seals and I'll get another few months out of it.

Mike on Freegle kindly gave me this neat little LCD TV he'd finished with. Now that analogue broadcasts have stopped and 4G seems to be the future for watching TV, these old sets are obsolete, but this one has an A/V input so it can be used as a dinky monitor. It's a bit small for raw Raspberry Pi, but I want to try it with the Arduino TV-out library to see what that could do. If I ever got the hang of GUI coding it might be possible to make something with big buttons. 

Finally found a use for the Raspberry Pi. Finlay was introduced to Minecraft on the school iPad, but since we don't 'do' Apple (spits in disdain), we have it running on a Raspberry Pi (old 256Mb version). Going to try it with a Bluetooth keyboard next. Must get around to trying XMBC too.

This is my experimental mini radiator for the downstairs loo made from scrap 28mm copper pipe and some spare fittings. I got the idea after finding an old photo of the bio-fuel heat exchanger I made almost 10 years ago. It's painted matt black to maximise radiation (finally found a use for O-level physics). So far it isn't working too well. Airlock is one problem I need to consider, but I also have a suspicion that the TRV valve may have stuck after more than a year screwed down closed. I'll investigate further. UPDATE - Seems to have been an airlock which has cleared itself elsewhere in the system, hopefully right to the top!

This neat portable hard drive is just 80GB, but it cost under £3. The drive itself was salvaged from a laptop that had come to the end of its useful life and I got the aluminium case with USB/SATA adaptor on eBay for just over £2 including postage all the way from Hong Kong. The brightly-coloured protective soft case was courtesy of my darling other half (it was a make-up bag of some sort!) and is just the right size for the drive. Home brew portable hard drive