Saturday 28 May 2016

Oregon tap & go 539137

My Stihl strimmer has a fixed feed line, which is ok except when you're working a lot of edging. Then it's tiring stopping to unscrew the bolt and let some more line out.
I've had a number of Oregon products and found them good. Mainly safety gear, but the odd chain.
I found the tap & go product which is suitable 'for most' strimmers above 33cc. So I bought one.  Nice product.  To re-fill it, you simply feed it through the holes and turn the dail to load the line in. Great. 
The on-line instructions and video make it clear that it will only work with  20mm spigot, which I have. So I open it up and lo, its a 25mm hole with a reducing ring. Sigh. So I fit it and it is so off centre, the whole strimmer vibrates violently; it is painful to hold the controls. I take it all apart and try to re-centre it. The reducing ring is about 0.4mm different diameter to the hole in the product, so no matter how carefully you install it, it will always be off. The ring is also thicker than the product, so if you have a flat washer with your strimmer (as shown in the video), it won't hold the base in place and it'll wobble.
I've asked Oregon to send me a replacement.
Oregon wanted very much to help, but this involved me travelling 2 hours to my nearest dealer. In the end I got a full refund of Amazon, who didn't want it returned.
So with nothing to lose, I made an accurate 20mm hole in a large washer, which I tacked into position with a run-out of 0.3mm. It was a bit better. A friend suggested balancing the head on a marble and adding weights to get it level. Pretty tricky (read impossible) but I think I found the balance point, so added 2 M5 bolts with blu-tack. There wasn't really enough space to fit them, but it was a test. They flew straight off. I noted the the large alu button that comes with the head is held on with 2 bolts, which don't appear to be balanced up.
Abandoned project! Off to get a Stihl 46-2

Friday 27 May 2016

Dewalt battery

New dewalt pack made from irobot cleaner pack for 510/530 series.
Downtown direct. 3Ah. No manf date or cell make. £3 amazon.
The box it came in, and almost fitted, states the cells are samsung or sony. It also states this is a li-on pack, so little confidence there.
Cells are stamped cbt-sc30mk18 c03
22 x 43mm 
First test with a 1.1A load gave a running time of about 2.5 hours (~2.7Ah), so the cells were pretty well charged.

Bought another irobot battery pack in July 2016. This time a BAKTH 14.4V 4000mAh Replacement NiMH Battery for iRobot Roomba 400 series Vacuum Cleaner at £6.70. No manf date. A bit of charge left.
They are no-name cells inside. Poor spot welding. This replaces the 2Ah AEG pack, which I'm moving to the Wickes drill, which replaces a bunch of AA cells which just don't have the umph.
From fully charged, a constant 1A load was applied and got forgotten about until the battery was down to around 1V. A very gentle recharge was applied for 10 + hours, but whilst the volts rose steadily to 15V set point, the charge current stayed 0.4A (C/10) and even when the volts were reduced to 14.4, current dropped off, then stayed at 0.4A.
A discharge with the dewalt lamp (9V cut off, 0.7A load) gave around 4.5 hours, or 3.15Ah. Not very impressive. Currently on the normal charger; takes about 2h and gets pretty hot.

Thursday 26 May 2016

Reversing camera

After looking at all the various options for a reversing camera, Amazon had a monitor and small reversing camera for a tiny £7. Not expecting a huge amount, I ordered it.
Really quite good. The camera is small and mirrors the image correctly. It even puts coloured lines on, but they aren't that useful, even though they've had a go at parallax correction; the start of the red zone varies from 30cm on the ground to around 10cm at the bumper.
Installation was interesting with the cable provided with the camera. A combined power and video with a phono. The power cable has a smaller 2.1mm barrel plug. The umbilical from boot to car is a bit tight, but a bit of water based conduit lubricant sorted that. Then snaking it through the car is fairly straight forward. I was a bit time constrained, so the monitor is loose in a change tray, and the lot is powered off a cigar plug. The camera is about 20mm diametre.  It is readily obvious sticking down about 20mm from the trim above the number plate. It doesn't protrude at all.  I could have hacked the plastic panel that it sits on, next to the plate lights, but it would still be visible by about 10mm.
Works well and I can just see the tow ball and the bumper about a metre either side at the closest, and about 3-4m away up to 1.2m high.
Another hour or so spent trying to find the reversing light wiring.  The lamp is set into the bumper on the right side. You can't replace the lamp or get the fitting out without removing the bumper. Thanks Renault. You didn't learn from all the negative feedback received when you so 'cleverly' required the removal of the front wheel on the Laguna? to change the headlight.  The wiring (pink + black at the light), it turns out, snakes inside the bumper, picking up the reversing sensors and the fog light, then comes inside on the left side. From the installation manual for the tow bar, it looks like the fog light and stop light are hard wired from the front. The reversing lamp is too. The connector is just by the rear left passenger door - remove the trim that starts in the boot - 4 screws. If you already had a main dealer install the tow bar, then expect all the clips that hold the panel to the car to be broken too. Thanks Renault. €400 well spent for a waster in a grey boiler suit who can't be arsed to go to the stores and get a handful of clips. Well, it's not written in the instructions. I note the instructions are pictures with no words, so that might explain it.
The cable from the camera was split out and + & - wired up. The -ve to a handy chassis bolt and the positive to the reversing wire - purple/white (not pink, thanks Reno) I think, pushed into the connector and tyrapped it. A 800mA fuse protects it. I might put in a delay timer to keep the camera on for a few seconds after coming out of reverse, as there is a 1.5mm permanent power feed there too protected by a 20A fuse if the tow bar instructions are correct - feed for the trailer canbus unit (1/4" faston). Reverse signal was not available there, despite there being 5 unused terminals!
The voltage on the rev light was 11.5 during normal use (battery about 12.5v) After splicing int he camera (about 0.3A) it dropped to 11.35v. The cable to the monitor is very thin and it was about 10.9 there. The pair operate ok down to 9V and below, but there is a bit of line break creeping in then.



The delay timer I added.  Simple RC circuit, transistor and relay



Tuesday 24 May 2016

Hedges cut

East side annual cut. About 80m. 3 hours. 2 trailer loads of bramble etc.

Wednesday 11 May 2016

MT-09 auxilliary power connector

Those nice people at Yamaha live in the real world. They know you're going to hack in a supply for your GPS or mobile, so they've already installed a fused (2A) connector and put it under the RH fake air intake. Just pop the centre out of the 2 plastic clips, accessed from the fork side, then the single hex bolt. Ignore the 2 hex bolts holding the grill mesh in place.
The connector is supplied with mating half, but no pins. These are readily available from the USA, which to order 2 costs around £15 delivered. I couldn't find anything on the Yamaha site; they sell the normal hack adaptor with spade connectors to go direct onto the battery.
So, time to hack something together.


The pins started life as a cheap automotive pin crimp. Ampliversal ones are too well built to use. Remove the red cover, squash the hole a bit so that it fits the aperture in the mating half, the file a notch, and cut it to length. I did it at about 7mm, but try 9mm. Solder some wires on and push it in until it clicks. You're supposed to have waterproof ferrules too, but just push the original ones back in. Then mate.
You can get waterproof connectors on ebay, but I just used a standard 2.1mm barrel connector which I tuck back under the air intake. It's what I had on the old bike for 11 years and it never got wet or rusted.  I've got a flying lead from the tank bag to a small 12/5V adapter. It's about 80% efficient, meaning the 12V x 2A = 24W from the bike can supply 24W / 5V * 0.8 = 3.8A@5V plenty for even the thirstiest products.

I then made the USB adapter.
I forgot to take pictures as I went, but the shot below gives you an idea




The pcb is a generic switching regulator, normally around 5 for £1 delivered. Takes up to 28V in and delivers up to 28V ish out.
I set it for 5.25V, as most branded USB adapters I've tried give out around this, or a bit higher. I had a spare USB socket, which I soldered to the PCB by flattening out the through hole tabs. Short the middle pins together to make it simulate a DCP (dedicated charging port - see https://www.maximintegrated.com/en/app-notes/index.mvp/id/4803 for a factual description of how to make your USB appliances draw more than 0.5A, or see pretty much any hobby site for rants abouts Apple's 'secret' wiring etc, etc) I did note in testing that my Samsung tablet would only take 1.2 - 1.4A with shorted pins, but would go to 1.51A with 300 + 100k resistors wired +5/0V to the shorted pins.  It was fairly unscientific and for all I know it just needed less current at some times when it was charging. The official charger showed 1.8A. Life was too short to get too technical.  All I want is a charger for the phone or GPS etc on the bike if I'm caught short.
The picture is taken during a soak test at around an amp. I say 'around' as the little meter thingy is about 10% accurate on amps, and 5% on volts.
A SMD LED next to the socket gives you power on indication with the plug removed.  A piece of heat shrink finished it off.  I didnt fit a fuse as the bike has a 2A. 
Through the heat shrink, it feels like the chip is running at about 60C, which is pretty good considering there is no airflow. The chip, a MP1584, has a maximum dissipation of 2.5W, which IIRC gives a practical limit of around 5V/1.0A before the chip shuts down as the die hits 150C, assuming 14V in, 85% efficiency
5W out, 5.9W in = 14V@0.42A. Vd = 14-5 = 9V x .42 = 3.8W dissipated.  Oops. Working that back for 2.5W gives 5V@0.66A
Perhaps I should have left the D+/D- floating to limit the draw to 0.5A
A soak test for an hour at 1A has been OK, so I guess the heat shrink is radiating a bit, plus the USB plug will be an external heatsink.