• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

Hermes-BBB/Botic cape for BeagleBone Black

I just removed my battery and unbridged j1 and all seems well for now with the same 5v supply
864d3c1587a6a7bd3fc9c0d2183e2c9d.jpg

I removed the soldered j1 bridge and added a male header so I can bridge easily later
3e31535cbab2a37698092461f10adc09.jpg

Obviously I'd like to get it working with the battery if possible. Any pointers?
Thanks,
James
 
I just removed my battery and unbridged j1 and all seems well for now with the same 5v supply
864d3c1587a6a7bd3fc9c0d2183e2c9d.jpg

I removed the soldered j1 bridge and added a male header so I can bridge easily later
3e31535cbab2a37698092461f10adc09.jpg

Obviously I'd like to get it working with the battery if possible. Any pointers?
Thanks,
James

hi james,

my experience is that the bbb+hermes get a lot of current during the start up. so a stable 5v psu of minimum 1,5A should be used to operate (better even 2A when connecting other stuffs to the USB, LAN...). In your case maybe the situation gets even worst if the battery is connected and the battery is beeing charged and consume additional power.
 
Q1. should the resistor value be 75k instead of 10k?
Regarding battery connection, I will answer my own question: the Hermes board is set up for a battery with NO temperature-sense wire. The 10k resistor on the Hermes simulates the presence of a temperature thermistor, to satisfy the BBB's charging circuit.

For anyone wanting to connect a 3-wire battery with temperature-sensing, you should change this resistor to 75k. In such case, it's probably easier to wire directly to the BBB, instead of via the Hermes.

I still wonder about the absence of a capacitor across the battery, since the LiPO charging chips I have seen on the web all specify one.
 
The capacitance is already present later downstream - and is not required in the least at the hermes end. 🙂

The hermes-bbb come ready for the two wire self protected batteries - because that is a simple inexpensive option. Three wire types and even separate NTC type batteries can also be used but as you said you may need to change the NTC linearizing resistor.

The best call is to use the 2 wire internally protected batteries - as we have suggested. The Hermes-BBB comes ready for these. For 3 wire or 2wire + 2 wire NTC (all supported by the Hermes-BBB) you will need to do a little research on your own. 🙂
 
I added a note on the first page about battery selection. I hope that helps.

The problem with 3 wire and separate NTC battery selection is that you will get no protection from undervoltage nor overcurrent prior to the BBB (example accidental short).

The 2 wire self protected (against over voltage, temp, over current, under voltage) are by far the safest option. In particular over-discharging a LiPo is a real concern - and a 3/4 wire solution won't protect you against that. The type we suggest won't allow the battery to over-discharge.
 
Thanks.
I was only aiming to use a 3-wire battery, myself, because certain web authors insisted it was the only safe way to go.
But your explanation about inbuilt protection circuits is assuring. I imagine that the over-charging/over-current protection feature should avoid the possibility of the battery temperature ever getting too high, anyway.
 
Can anyone suggest why my BBB refuses to start when I have the Hermes connected?!

I am just in the process of building my setup. BBB>Hermes>Cronus>BIIIse>IvyIII

Problem happens with only the Hermes plugged in to the BBB, with or without the Cronus plugged in. I've tried with power direct to the BBB and through the Hermes. With J1 jumped and open. I have the main connector and the four pin one connected.

When I connect the power, all I get is the power LED on the BBB flashing and LED3 on the Hermes flashes too. If I remove the cape, the BBB starts immediately power is applied.

Any ideas?

Thanks

Val
 
Last edited:
Can anyone suggest why my BBB refuses to start when I have the Hermes connected?!

I am just in the process of building my setup. BBB>Hermes>Cronus>BIIIse>IvyIII

Problem happens with only the Hermes plugged in to the BBB, with or without the Cronus plugged in. I've tried with power direct to the BBB and through the Hermes. With J1 jumped and open. I have the main connector and the four pin one connected.

When I connect the power, all I get is the power LED on the BBB flashing and LED3 on the Hermes flashes too. If I remove the cape, the BBB starts immediately power is applied.

Any ideas?

Thanks



Val
it seems you have an unsufficient psu connected to the hermes. try a strogner one and your problem will be most probably solved!
 
Thanks, but I suspect that this is not the problem, I have tried two different supplies, one is 2amp and the other 3amp. Monitoring the voltage shows that it is up at 5.1v with the power LED flashing.

ok, I understand. then your issue is probably different.
I had once connected a 1A psu to the hermes and the LEDs started to flash and the bbb stoped to boot. replacing the psu by a 2A one fixed the problem.
 
OK, so I have now got the BBB to boot, and installed Volumio, boticised it and confirmed that Botic is running.

I only have two LED's alight on Hermes, EN and 3 and no music getting through to the BIIIse.

Any ideas where to start?

So far, I have tried installing just Mieros Botic V4, same result.
Re-flowed all solder joints and checked all boards for any solder bridges.
Checked all LED's are the same way round!
I have no jumpers installed on Hermes, just the needed headers.

I'm now stumped and really do not know how or what to be checking!

thanks

Val
 
A bit of tip for comrade builders out there:

Ditch the wall wart PSU at some point if you want to enjoy the full fruits of this setup.

After troubleshooting what turned out to be a dodgy connector (argh, I could not for the life of me figure out what was going on), finally got my linear supply back up and running. Simple but good:
40VA myra isolation transformer (2 x 12v) + bridge rect + 2,200 uf 25V Rubycon ZL cap + Jung super-regulator -> BBB.
(actually I run 2 rails off the myra's 2 windings; 1 for the BBB and 1 for the hard drive. More for the B3, I-V and filters etc, but this exercise however only relates to the supply to the BBB. )

With a SMPS wallwart, the BBB-hermes-cronos is fabulous, but somehow clinical, analytical, cool, easier to walk away from.

Replace with a good linear supply, and boooom suddenly emotional engagement galore- Like the lady has had the third drink, decided you are indeed charming after all and is taking an almost embarrassing amount of interest in you. Its one that's hard to put a finger on, but I've found also comes with good grounding. Everything just gells somehow and I'm not ususally this inarticulate.
The BBB one might find an unusual candidate with mhz clock signals floating around and inside it, but after 20 years of modding and designing, IMO high frequency garbage is the silent killer of good audio and a devil to tackle well.

My two cents worth anyway.
cheers
Ced