Hello all,

I hope this is an appropriate forum to post this in. Google wasn’t turning up much help and this is very out of my wheelhouse.

I’m looking to build a small iPhone-sized touchscreen device that I can program myself. It would function as a simple notepad and recording device, so it would need a speaker, microphone, and SD card slot to store data. I would love to program the software in Python if possible.

Does anyone know where to start with something like this? I’ve heard of Arduino and Raspberry Pi, but I don’t understand how they could help.

Thanks so much!

 

It can be done with an Arduino but this project is quite complex for a beginner. What programming experience do you have and what is your level of understanding in electronics? There are many Arduino practical examples and forums available on the internet but it is a very steep learning curve. You will need to start with something much more basic than what you are proposing.

 

Probably the quickest and easiest will be using the PI Zero, but it will take some extras to get recording and playback. The a PI Zero is small enough to build a bulky iPhone size device, will have a built in LCD connector, runs from an SD card, and can use Python. It is essentially as close to a PC as you can get and works the same way. It will be slow to boot compared to building something from other parts and probably not very friendly to batteries if you want something battery powered.

The other end of the spectrum will be the Arduino, PIC, STM, and other controllers. As far as I know none of the microcontrollers have a Python interpreter available and your choices will either be C, Assembly, and possibly BASIC (depends on the controller). Arduino has LCD and SD card libraries already available to get you started. Some of the other microcontrollers have similar libraries also and for some you will have to start from scratch and write all your own code. Recording and playback will take some extra parts and circuits to get it to work. There are some chips available that can make that part of the project relatively easy compared to designing your own circuits, but it will still take some work to get it all going.

Judging from your question this may be an overly ambitious project at this point in time.

 

It can be done with an Arduino but this project is quite complex for a beginner. What programming experience do you have and what is your level of understanding in electronics? There are many Arduino practical examples and forums available on the internet but it is a very steep learning curve. You will need to start with something much more basic than what you are proposing.

I'm very comfortable in Python, not expert but a solid intermediate. I've used Swift and Java as well, just not as much. I'm comfortable soldering and working with small components. I've built guitar pedals, cables, and amplifiers.

Do you have anything in mind for a more simple project?

Thanks

 

Probably the quickest and easiest will be using the PI Zero, but it will take some extras to get recording and playback. The a PI Zero is small enough to build a bulky iPhone size device, will have a built in LCD connector, runs from an SD card, and can use Python. It is essentially as close to a PC as you can get and works the same way. It will be slow to boot compared to building something from other parts and probably not very friendly to batteries if you want something battery powered.

The other end of the spectrum will be the Arduino, PIC, STM, and other controllers. As far as I know none of the microcontrollers have a Python interpreter available and your choices will either be C, Assembly, and possibly BASIC (depends on the controller). Arduino has LCD and SD card libraries already available to get you started. Some of the other microcontrollers have similar libraries also and for some you will have to start from scratch and write all your own code. Recording and playback will take some extra parts and circuits to get it to work. There are some chips available that can make that part of the project relatively easy compared to designing your own circuits, but it will still take some work to get it all going.

Judging from your question this may be an overly ambitious project at this point in time.

Did you have any specifics in mind for the recording and playback, which chips? The goal is to have something I can carry with me in my pocket so a battery is necessary.

Thanks

 

There is a 2.4" touchscreen TFT display which would be ideal for your project. You can buy it as a display module with built-in drivers or as a module that will plug directly onto an Arduino uno or mega. It has a built-n micro SD card reader. There is a url to a tutorial on it below. I would recommend that you get one and get to know how to program the display and touch panel. Write a basic program for it, e.g. a simple 4 function calculator. That will give you experience with displayng alpha and graphics and using the touch screen. There are tutorials on line for recording and playing back voice with the card reader.
https://www.instructables.com/How-to-use-24-inch-TFT-LCD-SPFD5408-with-Arduino-U/
https://circuitdigest.com/microcont...no-voice-recorder-for-spy-bug-voice-recording

 

Did you have any specifics in mind for the recording and playback, which chips? The goal is to have something I can carry with me in my pocket so a battery is necessary.

Thanks

The PI Zero won't help much then and more or less overkill anyways. The PI Pico https://www.raspberrypi.org/documentation/pico/getting-started/ looks promising though. It actually does include Python support. I just ran found mention of it on another thread and after a quick check thought I was worth mentioning.

As far as chips go I don't have any specific parts to mention. I've looked at a few projects here and there, but never tried myself. There are some Arduino audio recorders you might get some ideas from. Other than that you'll just have to look around until something catches your eye.

 

Your best bet would be to reprogram a cell phone.

Bob

 

Just had a thought and @BobTPH pretty much beat me to it. In all reality a simple tablet should be able to do everything you need for the same cost if not less and 90% less headaches. Of course if you want to do it anyways then good luck and keep asking questions.

 

Your best bet would be to reprogram a cell phone.

Bob

Could you elaborate? How would I begin?

 

Just had a thought and @BobTPH pretty much beat me to it. In all reality a simple tablet should be able to do everything you need for the same cost if not less and 90% less headaches. Of course if you want to do it anyways then good luck and keep asking questions.

Yea definitely sounds like an option. My only worry would be replacing old parts as the device starts to age. How would I go about removing the current software and putting my own software on it?

 

The PI Zero won't help much then and more or less overkill anyways. The PI Pico https://www.raspberrypi.org/documentation/pico/getting-started/ looks promising though. It actually does include Python support. I just ran found mention of it on another thread and after a quick check thought I was worth mentioning.

As far as chips go I don't have any specific parts to mention. I've looked at a few projects here and there, but never tried myself. There are some Arduino audio recorders you might get some ideas from. Other than that you'll just have to look around until something catches your eye.

The pico looks nice, and micropython sounds like another name for python 3, which I could easily get into. How would you attach a touchscreen and battery?

 

Have a look at STM32F746GDISCOVERY.

 

Yea definitely sounds like an option. My only worry would be replacing old parts as the device starts to age. How would I go about removing the current software and putting my own software on it?

That’s another argument for using custom software on a smartphone. It becomes much more independent of hardware. I’ve developed iOS apps that run on just about every iOS device still running.

I don’t mean to minimize the difficulty of writing software but it frees you from worrying about the hardware also.

 

That project would be fairly complex for an engineering professional, unless a bunch of application specific modules were available, and then it would still be complex.

 

It’s a trivial project at the software level. In fact an iPhone already does everything mentioned without additional software.

 

How would you attach a touchscreen and battery?

The battery part is easy, the charging part I don't have any experience.

The touchscreen depends. Some are simple two to four wire serial connections (SPI, I2C, UART) while others can be up around 40 pin parallel connections. Some have a dedicated touch controllers that will give you coordinates while others you have to measure voltages of pins and calculate the position from that. The common displays have all sorts of tutorials, code, and help scattered across the internet. Search arduino lcd to get some ideas.

Just make sure to research the best you can before buying a display. Some cheaper offerings don't always list the correct controllers in the specifications and that can lead to a lot of headaches (or in the case of one I bought a fancy paper weight).

 

It’s a trivial project at the software level. In fact an iPhone already does everything mentioned without additional software.

There is nothing at all trivial about the software in an iphone!! It is just well hidden.

 

It’s a trivial project at the software level. In fact an iPhone already does everything mentioned without additional software.

I'm not too concerned about writing the software either. iPhones are great, that's my daily driver, I personally still want a standalone recording and note-taking device, for simplicity.

 

That project would be fairly complex for an engineering professional, unless a bunch of application specific modules were available, and then it would still be complex.

Sounds like a great learning experience.