This week, mostly, I have been soldering......
It's been a busy week, with 2 new arrivals - Nanode 5 and a new DSP microcontroller board I am developing for work.
Sunday 8th May
Make hopefully final changes to Nanode 5 pcb schemeatic and layout. Send off to Roger Light so that he can add the London Hackspace logo onto the correct layer and give it a check over.
More tinkering with my solar heating controller code, and get a chance in the evening to cut the grass, which was way overdue because of my week trip to Wales.
Monday 9th May.
Receive files back from Roger, but notice that there are one or two areas of the screen print layer which could be improved. I edit just this layer and recompile the design to produce a zip file containing all the Gerber files and drill file needed for manufacture.
Tuesday 10th May
I contact Spirit Circuits in Hampshire to get a quote, and apply to have a free "Naked" pcb done as a trial sample to prove the design. The naked pcb is basically a low cost advertising device for Spitit Circuits, where they produce your board for free in 48 hours in the middle of a larger board which contains their latest ad-campaign messages. I send off the gerbers and get an email in the afternoon to say that my naked sample will be with me on the 12th.
Travel up to the Gypsy Moth pub near Greenwich Pier. Have an enjoyable evening of strawberry "Fruili" beers wit my nephew Adam and his college mates who were celebrating his 21st birthday. Get home a little worse for wear, having rushed across town on the DLR through Docklands and tube to Victoria to catch the 23:37 home to Redhill.
Wednesday 11th May.
First of the DSP/microcontroller boards arrives at work. I spend the morning building up the board and have it flashing LEDs by the afternoon. I had to order some thin solder (26 gauge) and some surface mount flux in order to make a reasonable job of the SMT assembly. Finished the day wishing that a) I still had the eyesight I had when I was 30 and b) wish I was a more competent C programmer.
Thursday 12th May
Complete the SMT build of the DSP board at work and continue testing. Arrive home to find that Naked Nanode has arrived! Too much eyestrain to start building it tonight - will do it tomorrow after work.
Informed the London Hackspace of a proposed "Nanode Weekend" for 4th and 5th of June. This will be the official launch of the Nanode, which will include a distribution of the kits, a DIY build session (with experts on hand) and a full day of instruction about the Nanode programming and Apps. If we get 10 people who can solder, I intend to set up a short production line, so that we can build lots of boards to a high standard in a relatively short time.
Friday 13th May.
Not a good start. For some reason the USB JTAG emulator I use to load code into the DSP packs up - after I unplugged it from the board. I spend 2 hours rebooting machine, re-loading drivers etc, only to find on the manufacturers website that this is a known issue, and it happens when you plug another FTDI serial device into the PC. If the JTAG, which uses the FTDI chip is removed, priority goes to the 2nd device and that stops the JTAG from being recognised. I spent half a morning dealing with this totally crap issue, which is so typical of the computer industry releasing badly thought through products.
As a consequence my 1pm Friday finish was delayed to 16:45pm, but I did get a lot more debugging done without the interruptions of phone and co-workers. I also sent off for an Ebay batch of Nanode boards, where you get a square foot of boards for £37. This works out at about £2 per pcb. These will be ready about May 30th.
Friday evening 6pm - time to start building up the Nanode 5 board and test it. Because of the lack of solder resist layer you need to be very careful soldering - as it is way too easy to get shorts between adjacent tracks and pads. By 7:30pm the board was running code on the ATmega and printing out readings to the serial window. A brief interruption to go for a pub meal with Elaine, and then back to debugging Nanode 5.
Unfortunately, the only 3V3 voltage regulator I could find was a very old Holtek 7533. These are only good for 100mA - which is really not enough to run the ENC28J60 ethernet controller chip. As a result the 3V3 rail sags to about 2.9V which is not enough for ethernet comms. I adopt a trick of using 3V3 "jump leads" from another Nanode board, and the ethernet springs to life - first with a successful response to a ping and then serving a full webpage.
Saturday 14th May
Intend to document some of the week's proceedings and work with the guys developing the Nanode application software so that its ready for the Nanode launch in three weekend's time.
Sunday 15th May
I expect I will be resting or pottering in the garden - as I am sure the grass will need cutting again.