Powering the pyboard
Re: Powering the pyboard
OK, I'll take your word for it - physics, electronics and programming are not my strong points
Re: Powering the pyboard
Hi. It looks that my CAN bus project (based on PyBoard) is going to be powered from OBD2 port or any other way that will be possible to connect to in car (which has 12V). So here are some questions:
1) Which voltage regulator is better to use (12V -> 3.3V, but I have heard that in car it can jump from ~7V to ~15V)?
2) What max. current PyBoard is able to handle before it dies?
3) Which pin should I connect my "regulated" power to? V+ or VBAT?
Not an electrician guy, sorry )
Actually I'm thinking about this one
1) Which voltage regulator is better to use (12V -> 3.3V, but I have heard that in car it can jump from ~7V to ~15V)?
2) What max. current PyBoard is able to handle before it dies?
3) Which pin should I connect my "regulated" power to? V+ or VBAT?
Not an electrician guy, sorry )
Actually I'm thinking about this one
- pythoncoder
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Re: Powering the pyboard
@PinkInk Re self balancing robots you might like to look at this thread http://forum.micropython.org/viewtopic. ... =balancing. There are a few of us who have built these, including my effort at the bottom of page 3. A brief tl;dr summary:
- You need a gyroscope and an accelerometer. The readings can be combined using Kalman filtering or by complementary filters. The latter is simpler and works well.
- You need a grasp of PID controllers. These are easy to implement but you do need to understand the basic concepts.
- As others have said, keep the mass high. Mine has a 12V lead acid gel battery at the top!
- It is vital to mechanically isolate the gyro/accelerometer from vibration. My first attempt had to be completely redesigned because I hadn't appreciated the level of vibration (+- 2G).
Peter Hinch
Index to my micropython libraries.
Index to my micropython libraries.
Re: Powering the pyboard
@kamikaze. Just a few comment about powering Pyboard:
- you may either use VBAT or V+. VBAT ends up at V+, so use V+. DO NOT USE Vbackup!
- at V+ or VBAT at least 3.6 V must be supplied.
- the internal regulator of PyBoard is always active. I can handle 250 mA at a maximum of about 1 W power dissaption, which is (V+ - 3.3)/current. That means, the higher the input voltage, the lower the current you can draw. At 12V, 250 mA, the power is 2.18 W, at which point the regulator will overheat and break. That's why Dave suggested to power PyBoard with 5V and use an external regulator.
- Setting up a switching regulator by yourself is tricky. Better buy one of the prebuild 5v regulator modules like the pololu devices, or simply use a linear regulator like LM7805 or the like, if power efficiency is not the matter.
- you may either use VBAT or V+. VBAT ends up at V+, so use V+. DO NOT USE Vbackup!
- at V+ or VBAT at least 3.6 V must be supplied.
- the internal regulator of PyBoard is always active. I can handle 250 mA at a maximum of about 1 W power dissaption, which is (V+ - 3.3)/current. That means, the higher the input voltage, the lower the current you can draw. At 12V, 250 mA, the power is 2.18 W, at which point the regulator will overheat and break. That's why Dave suggested to power PyBoard with 5V and use an external regulator.
- Setting up a switching regulator by yourself is tricky. Better buy one of the prebuild 5v regulator modules like the pololu devices, or simply use a linear regulator like LM7805 or the like, if power efficiency is not the matter.
- JonHylands
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Re: Powering the pyboard
I've used this switching regulator to get 12 volts down to 5 volts for my custom pyboards:
https://www.pololu.com/product/2119
That regulator could also be powered from a 2 cell or even a 1-cell lipo if needed, since it can both switch up and switch down.
- Jon
https://www.pololu.com/product/2119
That regulator could also be powered from a 2 cell or even a 1-cell lipo if needed, since it can both switch up and switch down.
- Jon
Re: Powering the pyboard
Better use this one: https://www.pololu.com/product/2121 or this one: https://www.pololu.com/product/2843
since the input voltage in a 12 V car can exceed 11.8 V. When the engine runs, you'll typically see about 14V.
since the input voltage in a 12 V car can exceed 11.8 V. When the engine runs, you'll typically see about 14V.
- JonHylands
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Re: Powering the pyboard
Actually, you're right - I only use that regulator with a 1s or 2s lipo, so max of about 8.4 volts in.
- Jon
- Jon
Re: Powering the pyboard
Just a warning.
On the early pyboards, VBAT is the backup battery for the RTC. On the newer boards, VBAT is for powering the pyboard using a battery and the RTC battery is called Vbackup.
On the early pyboards, VBAT is the backup battery for the RTC. On the newer boards, VBAT is for powering the pyboard using a battery and the RTC battery is called Vbackup.
Re: Powering the pyboard
From main page:
Does it mean that I should step-down voltage to 3.6V because 3.3V is not enough?On-board 3.3V LDO voltage regulator, capable of supplying up to 250mA, input voltage range 3.6V to 16V
- JonHylands
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Re: Powering the pyboard
3.3 volts definitely isn't enough - you have to provide 3.6 volts as an absolute minimum, but realistically you're better off providing 5 volts, just like it would get if it is plugged into USB.kamikaze wrote: Does it mean that I should step-down voltage to 3.6V because 3.3V is not enough?
- Jon