A couple of weeks ago, I had dinner with Pete Lomas, the Raspberry Pi Foundation trustee and all round good bloke who did the hardware design for the Raspberry Pi. It was a good opportunity to put some of the questions our Twitter followers had sent to him. (You may have seen Pete in some of our videos – he’s the fella in the lab coat and tartan trousers with the soldering iron and a fistful of capacitors.) At some point the names of those asking the questions went adrift from the questions themselves (entirely my fault) – if you asked one of these and would like to be acknowledged, please leave a comment below!
Pete’s answering questions here rather than on Twitter because he is constitutionally incapable of expressing himself in fewer than 140 characters. Over to Pete:
Why do birds suddenly appear every time you are near?
Cos I have bird seed in my pocket – why else?
Will RAM upgrades be available soon? And do you think you will move towards the multi processor boards?
We are looking at the possibility of a Model B+ with additional RAM, but the costs do not look promising and unless we really run out of space for the cool stuff people want to do then it will be a while
Why is the Pi selective about SD cards it will work with, surely the SD SDHC is a standard? [[Liz: This is about the problems we've had with Class 10 cards.]]
It looks like the jump to smaller die and process has created some anomalies that for some reason the BCM2835 cannot handle, this is also reflected in issues with Class 10. We will publish a tested list but we have already found that the same Card manufactured in different years – have different die, the early one is OK and the later one not. This is an issue and a real pain but we are looking at it. It also affects microSD cards for identical reasons.
What beer do you like?
Peroni & Guinness – how end of the spectrum can you get. [[Liz: I will point out here that while Pete is trying to present himself as the Common Man in his beverage choices, we *did* spot a bottle of Cristal on his desk just before Christmas.]]
Are you surprised by the demand, or just feeling quietly justified that you’ve made something really cool that everyone wants?
Overwhelmed – never justified – we have a target to get these in schools and filling that gap – that’s my focus. However my 9 yr old son tells me its cool!
How to be so awesome?
(Do I even understand the question) I’d say do your best – s**t happens – but keep focused and you’ll get there…eventually. That’s what I kept telling myself trying to route out the BGA…
Why alre the USB ports so misaligned with the ethernet one?! Ok, I know the answer, but tell him – crying – all the same!
When I saw the prototype I realised I’d messed this one up – my PCB symbol’s outline was just plain wrong – makes cases kind of interesting. Eben is threatening to buy me beer until I agree to fix it – I think we will as soon as we spin.
Why no sound input on RPi ? (could have used the same audio jack but with 4 contacts – like on a mobile phone)
There are no inbuilt Audio ADC’s so there would be a cost adder – everyone was sat on my head to get costs down. They can be easily added via the GPIO.
Was there ever consideration to put Bluetooth on the Pi?
Would have been really cool but the budget would be blown - Bluetooth to USB is the way to go.
No holes, difficult casing Why not microSD and combined composite video + stereo jack to free some board space?
OK but mounting holes cost 7-8mm diameter where no tracks can go – could not see any sensible locations without compromising I/O. In plastic it is quite easy to mould catches – there is something on the way…
Ask him if there is anything he would have done differently, knowing what he knows now? Also – What was the biggest sacrifice?
There are a few niggles with the design, mounting holes, connector alignment but in the basic design, but no, it does the job. The biggest sacrifice….hmmm staying sober to do the layout …..seriously if it achieves the goal we have set – its awesomely worth it . Thanks for your support.
Can the fuses at USB be safely removed to provide >140 mA to USB or is there power concern that requires the limitation? [[Liz: I believe this is a question of interest to almost nobody but Abishur, but asked Pete to answer it because Abishur is a very helpful fellow around these parts!]]
The fuses kick in hard around 280mA and fold back and limit to 140mA. If you remove them then all you have for protection is the 700mA inbound fuse. The tracking on the board is good for 500mA+ so you could if you really wanted too. What about a powered hub – to power the Pi and bigger USB devices.
No questions, but please say THANK YOU PETE!
Thanks for you support – enjoy.