Poppy 1.1 : Hipi

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20 days without any news on the Hipi battlefront? Come on guys, we are starving out there :slight_smile:


Thank you for your motivation shot!
We are really busy now with the preparation of the “Colloque Robot Education”, but I still working on it when I have few seconds.
The main problem for now is the DC/DC power stabilisation, I work with TI about it.
If you have special skills about power electronics, you are welcome…


My main skill is enthusiasm :slight_smile:


@Nicolas, is it the noise? Or there is it about power?


To be more specific there is a problem on the TPS5427 DC/DC :

With this circuit I have a consequent switching noise who disallow SPI communication :

The input is pink and the output is yellow.


I’m doing my technical choice for a project (I can wait for a long time). Why didn’t you used the OpenCM9 board instead of creating a new one? http://support.robotis.com/en/product/auxdevice/controller/opencm9.04.htm


Because OpenCM9 don’t have any audio amplifier and IMU and with the Hipi we don’t have to manage other device code.


Could you consider making a Pi Zero hat in this case? I need something really really compact for my project, and I guess it’ll be useful in embedded projects :slight_smile:


Our problem around the Pi Zero is the absence of any network interfaces. If you need to use a zero, the hipi should be electrically compatible, but the driver needed to run it properly should take a large CPU ratio of your Zero, so you probably cant run properly something like Pypot to control your robot.
If you use at least 8 XL320 on your design consider using Pixl, cheaper and light in term of CPU usage.


I would control 17 servos, and I’ve read that 6 servos is the maximum for the Pixl board. Well, I’ve no other solution that using the OpenCM9. But the Pi Zero can easily get Wifi connexion through micro usb to usb adapter + a micro dongle.


Why Pixl would be lighter in CPU term compared to hipi? If I plan to use a OpenCM9, would you say the amount of CPU needed for serial communication could be higher than driving motors with hipi?

I’ve just seen that OpenCV could be hard on a Zero, because it doesn’t take part of GPU H/W acceleration, so now I’m thinking about a Pi B (2 or 3). I hope hipi will be thin enougth to be around the height of the USB port! :slight_smile: I’ll see all the possibilities, it’s exciting!


We have a specific driver needed for Hipi, so it’s a little bit more CPUvore.

It’s difficult to evaluate but this way could be lighter.

The Hipi will be probably bigger than that. You can download the 3D file of the Hipi in my last release : http://workspace.circuitmaker.com/Projects/Details/Poppy-project/Hipi


Is it a software driver for something not supported by the Linux kernel? (Not sure to understand)

I’ve seen the link but it’s a 2D map I don’t know how to read. Do you plan to create a 3D model (for cases modeling)?

I have another question, what does it mean? Which difference with the current Jack port on the Pi?


The Hipi allow to add 2 serial port on the RPI to do that we convert 1 SPI to 2 UART, and we need a specific driver to manage the specific hardware to do that.

There is a “hipi.step” file who is the 3D model.

The RPI don’t have any audio amplifier, it only have audio output, you can plug a headset or an amplifier+speaker.
The Hipi allow you to connect 3W speaker without additional audio amplifier.


Do you mean the audio amplifier can power a speaker over Jack? I don’t really understand what is an amplifier.

Last question, I’ve read Poppy Humanoid need two USB2AX to work properly over USB. Is it for this reason hipi uses two serials port? Then do you think OpenCM9.04 can drive 16 motors over one USB port without any lag?

Thank you for all your answers :slight_smile:


Amplifier is a question of power. If you put speaker on the RPI jack the sound will be very weak. With the amplifier the sound could be louder.[quote=“Vincent14, post:115, topic:2137”]

Last question, I’ve read Poppy Humanoid need two USB2AX to work properly over USB. Is it for this reason hipi uses two serials port?
I guess, better for the speed of communication.

On my side, I don’t know. Better way to know : test it :wink:


Nope. Currently no system can boast “no lag”. And the OpenCM9.04 does not have a performance-oriented firmware, so unless you develop something yourself, or patch the OpenCM libs to get good performance.
You can search this forum for more info on using the OpenCM9.04 as a usb to dynamixel replacement…


I have already done this search and posted my questions over there. When I speak about “lag”, I mean something unusable. Thanks for your precisions, I’ll keep that in mind :slight_smile:


@Nicolas Questions about the audio amplifier: how happy are you with the power? I have a TPA2012 equivalent module (Adafruit) with 2 3W speakers (8 ohm it’s true that reduces the output ) and I find the power of the output signal disappointing. I suspect that the output from Raspberry Pi is too low compared with the expected input for the chip (0.4-1.4 V).

Also, do you see any interference from the WiFi on board (if you use a Raspberry Pi 3) or a dongle?


The only trouble I have on the Hipi audio amplifier is probably due to power conversion module noise output. The power is pretty good if you put it on a head, the sound is not really good but it’s equivalent to the Poppy older version.

I use a RPI3 and I don’t see anything around Wifi…