Broadcom

I managed to wangle a free ticket to a talk given by the Raspberry Pi Foundation at Broadcom’s Cambridge Science Park office. Though this is but 100yards from my own place of work I had to bike in from home as I was on a day off.

I’d rather hoped to do the entire iPad thing and live Tweeted the even whilst blogging, but it didn’t quite work out that way. There were interesting presentations given by Lang, Bishop, Upton and Gert van Loo., and a lot of enthusiastic energy in the room.

Talking to some people there I’d have said though most were from Wireless technology companies, they were there due to personal [domestic] interest. That said three firms have short presentations on quite commercial applications using Raspberry Pi. I wasn’t convinced they really needed a Pi for their tasks but it did provide an adequately cheap capable platform.

I wanted a minute to chat to Gert van Loo at the end concerning his interface board but he was with someone one moment and swamped so much later on that even standing on a chair I couldn’t see the hardware. Ho hum.

Came home much encouraged by my own level of knowledge. Time to start building something.

Raspberry Pi IO

Well I found out why the Pi was having trouble bit-banging at 4200 baud. It seems it just can’t do it due to Linux multitasking. I thought he libraries would have that fixed but it seems not. This leaves only the hardware supported channels: UART, I2C and SPI. These at least should buffer some data and send it even if the processor is busy.

So after a bit of hacking I have two-way IO between the Pi and Arduino over the UART. I’ll try the SPI AND I2C another day but this means I can control the Arduino from the Pi and let the Arduino control peripheral hardware. Not ideal but further forward than before.

Next I’ll try using the Arduino UART to control my OLED display. This requires some detective work with a borrowed digital storage oscilloscope. I’m not sure what I’m doing wrong. It may not be possible. Alternatively I might turn to programming a Pic 18m and using that instead. That should work at 3.3v too.

So, finally all the comms are coming together so I better get planning on my first proper project.

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Snow Bound

Well I came home from work early today due to the snow and worked via VPN. Meanwhile The Nipper arrived back from school but parked himself in the front garden frolicking like a mad thing in the rapidly thawing snow. Never happier.

I spent the evening trying to get some Arduino software running on the Pi with no joy despite pushing the signal through my mini logic analyser to check it. Very strange. Getting more confident with this stuff though.

I really need a good oscilloscope though. That and lots of time.

Almost forgot to add: tomorrow is the Makerspace open evening. Worth trudging through the slush for.

Next Big Project

I own an exercise bike. It’s a pretty good one and I’ve had it for about 7 years. Trouble is I’ve not been on it since we discovered we were going to have a baby. Too much to do. Now we have a beautiful five year old boy, so it looks like I’ve not been on it for a while.

Said nipper is getting concerned about “Daddy’s big fat tummy”. It is true. I look like Daddy Pig from Peppa Pig. So I’m going to get a sticker reward chart like he nippers. Instead of getting a sticker for teeth-brushing or auto-dressing I’ll get one for 15 mins on the bike each night. A line of stickers gets me a coin and enough coins gets me … A CBeebies magazine? Perhaps not. Something though.

Anyway, the damn this has lain unused for so long the battery in the monitor has died. Corroded I seem to remember. I removed it a while ago as the piezo alarm kept beeping. New batteries didn’t help and I was going to junk it – until tonight. I’m a Maker and a Fixer now. So I stripped it down. Some loose hot-glue-gun glue was rattling around inside. That wasn’t it. The display seemed low contrast. No connectors looked loose nor were here any damaged components. The batteries were new. Eventually I scraped the battery connectors and some oxide came off. Good as new!

On he bike for 15mins full tilt. Sweating like Daddy Pig. I’ll build it up and try a bit of interval training soon.

Whilst pedalling I began to think: it has an exposed heart pulse sensor (contacts on the handle bars) and a rev speed counter. These are used to calculate a pile,of metrics on the unlit simple LCD display. If I were to instead [or in addition] attach them to an Arduino or Raspberry Pi then I can build my own monitor. The Pi could not only display it on a screen but also keep a log and present the results on a web page. It seems like a groovy project. So groovy that I think I’ll do it. A nice little marquee on my OLED display too.

Watch this space.

Hair Cut

I’m at the barbers behind a long queue. Thank God for free wifi. Then again it may have been easy to
Ask for the password in Mr Politos, but in John Lewis they demanded my email address and mobile number and the right to send me junk mail. I complied to stave off boredom. It access didn’t last long before it forgot who I was and went through the entire procedure again.
Why is public free wifi such a pain? Shirley the idea is to. Ale it available to people easily. Why piss off your customers? The Cloud seems to be the most aptly named wooly service ever. Still, looking a gift horse …
Back to the scalping. I’m in for a #1. I’m aiming to lop off my Jim Broadbent wrap around thinning locks and go for a look that says: honestly I have plenty of hair. It just choose to wear it short.
Thick hair has never been my forte. My hair is fine and was only thick and long at primary school in the 70s where in formed an impenetrable jungle that would not yield to the hack of an unforgiving parent’s comb. I was glad to see the back of it.
I don’t miss the wet after bath shiver. I relish my quick dry scalp. But things are different when I venture out into our post apocalyptic sun. There my pale Pictish skin decays painfully in the radiation. I’m expecting liver stops and lesions in old age. Oh yes, I will look the part if I make 80.
So I’m on for scraping my protective layer off now. 6 ahead of me in the queue. Hence the blogging. Time for my book now( Smut by Alan Benett)

UART

Well I now have the Raspberry Pi talking to an Arduino using the UART. I’m seeing my hello-world message popping out at the far end … mostly. It does seem to drop a character in a regular point, but that is probably a script issue.

I’m not echoing back the data yet but I guess that will work fine.

So technically I can send a message to the Arduino and then signal that to the OLED display.

I still a bit bemused that I can’t use the Pi’s GPIO pin to talk directly to the OLED display, even though it is using the same functions as the Arduino.

Still, it is progress.