Lil' Lights, Adventures in PCB's, FLIR and high power LED's

                        

                        

After designing the MTV robot I've been slowly tinkering with numerous add ons. I wanted to add some high power LED lights and so I bought some 1 watt white LED's in an SMD package. They offered a lot of light and I'd read that the 1 watt LED didn't need heatsinks to keep the running temperature within the datasheet operational temperature range. 

Testing them on the bench they get hot enough to be uncomfortable on the fingers so I decided that a PCB breakout that enabled them to be easily mounted but also acted as a slight heatsink was desirable. I quickly whipped up a design using the fabulous inkscape plugin SVG2Shenzhen and finished the design off in KiCAD . The PCB has a large pad that interfaces with the LED "slug" and in the PCB pad there are some via's connecting that pad to the large copper flood on the back of the PCB. This flood is under the mask so heat doesn't dissipate massively but I wanted it to just slightly reduce the temperature of the LED. When soldering on the LED I've added a small spot of thermal grease between the LED slug and the PCB pad. Finally I made sure that the M3 mount hole (3.2mm diameter for clearance) wasn't copper plated so that hopefully the heat in the LED and PCB wouldn't wick into mounting bolts etc. 

                        

I got some of the PCB made by the fantastic OSHpark  and mounted up some LED. Driving them at 1 watt is made simpler by using one of the cheap constant current capable DC-DC buck driver boards that are readily available now. They certainly are bright! 

                        

                        

I wanted to test how well everything was working and a friend kindly lent me his very nice FLIR camera. You can see a couple of things below comparing images from both mounted and unmounted LED's, firstly the PCB does indeed reduce the overall temperature a little as compared to the unmounted LED. Rather splendidly you can also see that the PCB mount hole doesn't couple and transfer the heat which is nice to know when bolting them into 3d printed parts. 

                

Above left is the front of an unmounted 1 watt LED. Above Right is the front of an LED mounted on the PCB

Above left is the unmounted LED rear and above right is the rear of the PCB with mounted LED.

                                

Above is a FLIR image of an M3 bolt placed through the mount hole of a PCB mounted LED. 

Get in touch if you are interested in getting any of these boards as I might put some on a tindie shop at some point. 

Unboxing and quick review of the Valenta Off Roader robot kit.

Quick video unboxing and assembling a Valenta Off ROader robot I won in a twitter competition!

Budget Eyewear Options for Close Up Work!

I'm comfortably slipping into that age range where eye strain is easily found and when the "ready reader" glasses are not too far away at any given time. Although I have always used lenses and loupes for close up work I am wearing them more often for a an increased variety of tasks. I've been quite happy with my choices until recently when wearing ones with a traditional nose arms and pads have started to annoy my nose and cause a bit of soreness, probably due to wearing them and glasses more often! So in a fit of random old maker blogging I though I'd do a round up of my crop of cheap close up work systems!

First up above (and modelled below) are my oldest pair which are essentially a set of loupes on a wire frame with some LEDS. The LED's on this type are rubbish using none rechargeable little coin cells with fiddly little switches and inside pretty poor quality plastic cases that promise to be move-able into any position but rarely stay where you want them to be! The loupes themselves are pretty good and powerful but only put stuff in a working range/focus about 15mm away from them. Far to close for soldering etc but actually can be very useful for looking at tiny mechanisms or indeed for hunting solder bridges or inspecting small joint on PCB's. The loupes can be rotated away from the eye and so you can flip them on of off without removing the frame. They aren't that heavy so can be worn for long periods. 

Next up, below, is these white plastic frames with interchangeable lenses, mine came with a set of 5 lenses promising a range of magnification from 1.5 x through to 4x. The lenses themselves are in a separate box and snap into place and can be rotated which is nice in that you can adjust their position relative to your eye. I find the 1.5x magnification can still return me a working distance of around 20-25cm which I find quite nice in terms of SMD soldering and other small work. They have 2 white LED's mounted above the lens and you can tilt the LED mount down and up to change the angle of them which works well. These take 3 AAA batteries and they are mounted in the front of the frame. I've found these brilliant for a long time but noticed that the combination of a standard glasses type frame that balances over your ear and the batteries at the front makes them feel front heavy and that they might slip off. They never have to be honest but these are the ones that of late, due to increased usage and reliance on them have started making my nose a bit sore! I've found these available online for between £9 and £15.

As previously it seems only fair to let the resident supermodel show off how hot these make you look. :)

So finally we come to the new kids in town! Pictured below these are similar to the last pair but I wanted to try a set that had a headband arrangement rather than a spectacle type set up. This set have a nice around 40mm wide padded and adjustable headband which can be set up to suit the wearer. They offer lots of support and the whole of the white assembly can be rotated up and down without removing the headband. They have a set of lenses similar to the previous set (in fact they are interchangeable) but the 1.5x lens is permanently attached in the frame and you can add more lenses behind if needed. They also have this pop down loupe which I haven't really found use for as yet but it amuses me in how brilliantly dorkish it looks! This set have 3 LEDS and they are powered by 3 AA batteries. You can tilt and adjust the LED up and down and side to side and you can also remove the LED and batteries out of the headband as a complete unit. If you don't want this extra weight on the front and don't need the lighting this is a nice feature! The LED's in this set also have 2 power settings which I guess offers more flexibility. I've found this set online between £12 and £25 so shopping around is definitely worth it. 

This final set have totally got rid of the nose irritation the previous set started to give and they also feel way more secure on your head and are pretty comfortable for a long close up session... Again.. I leave it to readers discretion to work out how "cool" they might make you look!