Raspberry Pi Forums

Hi
I would like to run an idea past you. I have been working on these sequencers for a while now http://pi.hardwiredonline.co.uk/. I have built two of each and I would like to synchronise them for live performance's. I have been trying to work out the best way to do it.

A little back groud; All four device's are stand alone but networked ( I don't have 4 monitors so I use my laptop and remote sessions ), i.e in short there not controllers. PlayPi is a sample based sequencer and is written in Python and uses pygame for sample playback. FluxpPi is 303/groove box style sequencer also written Python and used PYO for wave generation and DSP.

After doing a lot of looking around, (Midi/OSC etc), I was thinking of using multicast. I was planning to use one Pi as a master, keeping track of time and tempo, and getting it to send a broadcasts over the network that the other would pick up with its time to start/stop or move on to the next step. In short its just a software hack for CV (control voltage).

Any comments?

Multicast UDP will work well for this. I would have it send start / stop / sequence_position commands as well as the regular sequence_position updates. Each pi should run it's own sequence and keep going in absence of any updates. When an update packet does come in it can shift it's own internal sequence slightly if necessary. This makes the system accept high load conditions and networking errors with fewer problems.

Thanks myoung008, I was glad when I read your response as I had already started coding it. The current running code holds the start/stop/step variables and more so it should line up quite nicely. Cheers!