2011-04-14 9:17 am Electronics and hacman
Found these the other day, may be handy for anyone doing something they want GPS assisted. I'm considering the em-411 for the quadcopter's GPS assist (as its the only self contained unit).
Datasheets
http://www.globalsat.com.tw/manual.php?menu=3
Hints for buying from DX:
- The prices are including shipping!
- If you're getting lots of things, do it in smaller orders. DX get everything you order shipped to them, then package it all up and ship it to you. Smaller packages means you'll get some items far quicker.
- Dont browse, you'll end up spending about £900 if my experience is anything to go by :P
- Some of the stuff will be fake, or crappy, but its largely cheap enough you can forget about it.
Other Cool stuff
Tonight i spent some time at HAC:Manchester reverse engineering the keyboard matrix on our speak and spell, in preparation for hooking it up to an MBED. Since nobody else has released this information (as far as i can tell), here is the pinout:
| pin | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|---|
| 1 | u | k | off | a | f | ? | p | z |
|---|
| 2 | v | l | go | b | g | & | q | ` |
|---|
| 11 | w | m | <- | c | h | ??? | r | # |
|---|
| 12 | x | n | " | d | i | :) | s | / |
|---|
| 13 | y | o | _ | e | j | on | t | return |
|---|
This means that when the 'off' button is pressed, for example, pin 1 and pin 5 will be connected together.
To read a matrix keyboard like this, we write some code that steps through the 'down' set of pins (1, 2, 11, 12, 13), holding them low one at a time, then checks each of the other pins (3-10) to see if anything is being held low. If so, we perform a lookup on the table above.
Code to follow next week!
2010-11-24 2:14 pm huxley and reprap
It turns out the BOM i was using from the Reprap Huxley page isnt complete, and i needed to buy some M3 hex-head machine screws in 30m, 20mm, and 12mm lengths.
I went to RS, where i had gotten my other hardware from, and priced them up... and just about had a heart attack! £50 extra on bolts wasnt something i really wanted to spend, so i went back to my old love, eBay!
There are loads of sellers of nuts and bolts and associated fripperies on eBay in packs of 100+, and you can decrease your parts cost by a LOT by getting nuts, bolts, washers etc from one of them.
After some discussion on the #reprap IRC channel, i settled on eBay seller 'boltmeup'
RS Price: £50, eBay Price: £14!
Also, i compared the stuff from RS i've already bought:
| Item | RS Price | eBay Price |
|---|
| M3 Nuts | £4.85 | £2.95 |
| M3 Washers | £1.66 | £1.15 |
| M6 Nuts | £8.30 | £7 |
| M6 Lock Nuts | £7.34 | £6.50 |
| M6 Washers | £3.03 | £2.78 |
| M6 Mudguard Washers | £4.87 | £3.80 |
| | £30.05 | £24.18 |
|---|
Only a £5 saving, but add that to the £36 saving from the bolts and it comes to enough for 4 pololu driver boards!
2010-11-22 12:00 pm build log, huxley and reprap
After checking my reprap fund, and finding out i had reached my £500 target seemingly without noticing it (!) I've started collecting parts to build a reprap Version 3 (Huxley).
I chose the Huxley due to the fact it is portabie, while still having a pretty big build area ~(150mm x 150mm x 75mm)
I'm making the base model, with some minor upgrades to parts:
- Nophead's Motor pulleys link
- Nophead's Power Resistor Heater Block link
- Whosawhatsis Wade-Type Geared Extruder link
- Whosawhatsis m6 pinch blocks link
- Simplified Pololu Stepper driver electronics link
I'm currently buying parts, and recording all the costs to This Spreadsheet
Total BoM should come to around £400, leaving me some money left over to buy some ABS / PLA to print with.
Today I went to FabLab Manchester with one mission, to create a case for my OpenBench Logic Sniffer, an awesome little device from dangerous prototypes and the gadget factory, which ships as a bare PCB.
I started off by measuring the OBLS (93mm x 48mm), and making a test box 5mm wider than it in each direction. I added some circles for bolt holes to the corners, and cut a test piece out of cardboard out using fablab's Epilog Laser Cutter.
This piece seemed to be the right size, so I drew up the second layer, with the middle cut out, and a 1cm wide space for the USB socket. this was printed and checked, and I proceeded to the third layer with cutouts for the header and the USB socket.
After I was happy with the measurements on this mockup case, I cut out a copy in clear acrylic:
Assembled it:
Disaster! I had given enough room for the USB plug, but not for the USB cable that plugs into it. I modified the top of the case with a cutout for the plug, and widened the USB hole to 12mm to compensate.
Cut out another copy with the modifications, and a prettier colour scheme:
Perfect!Download the Laser cutter files to make your own OBLS Case
