build_your_own_mobile_phone
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build_your_own_mobile_phone [2025/02/05 02:18] sausage created |
build_your_own_mobile_phone [2025/02/05 22:36] (current) sausage |
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| The last few days I've been like a pig in mud working through the T-A7670SA's feature set evaluating it for a project. I discovered that all the required hardware is present to build a working mobile phone. So of course, I went on a little tangent. This board has Bluetooth, WIFI, LTE, GPS, USB, solar charging, condenser mic input, speaker output, 18650 Battery Holder, TF Card slot, SIM slot and plenty of GPIO. | The last few days I've been like a pig in mud working through the T-A7670SA's feature set evaluating it for a project. I discovered that all the required hardware is present to build a working mobile phone. So of course, I went on a little tangent. This board has Bluetooth, WIFI, LTE, GPS, USB, solar charging, condenser mic input, speaker output, 18650 Battery Holder, TF Card slot, SIM slot and plenty of GPIO. | ||
| - | I'll walk you through how to work with the board, what to solder, how to send/receive SMS and how to send/receive calls using the just stock firmware. No code required. | + | I'll walk you through how to work with the board, what to solder, how to send/receive SMS and how to send/receive calls using just the stock firmware. No code required. |
| As there is no keypad or display, all interactions are done via USB/serial interface. Without adding interface and display hardware with our own firmware, there's only so far we can go. But we can do quite a lot as a first step. | As there is no keypad or display, all interactions are done via USB/serial interface. Without adding interface and display hardware with our own firmware, there's only so far we can go. But we can do quite a lot as a first step. | ||
| Line 19: | Line 19: | ||
| The microcontroller on board is the ESP32, so when it comes time to implement new hardware, I'll be using the command line ESP-IDF for development, but we won't be using it for this article. | The microcontroller on board is the ESP32, so when it comes time to implement new hardware, I'll be using the command line ESP-IDF for development, but we won't be using it for this article. | ||
| - | For communicating with the A7670SA LTE modem, I'll be using Putty. | + | For communicating with the A7670SA LTE modem via the ESP32, I'll be using Putty. |
| The A7670SA 4G supported bands are: B1-B5, B7-B8, B28, B66. | The A7670SA 4G supported bands are: B1-B5, B7-B8, B28, B66. | ||
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| - | ===== Hooking up the initial setup ===== | + | ===== The initial setup ===== |
| Before switching it on, it's worth putting your nano SIM card into the slot, and connecting the LTE antenna. You can start it without these, but with your SIM inserted all the auto configuration will connect up to your provider for you, and you'll get good results when testing the signal quality. | Before switching it on, it's worth putting your nano SIM card into the slot, and connecting the LTE antenna. You can start it without these, but with your SIM inserted all the auto configuration will connect up to your provider for you, and you'll get good results when testing the signal quality. | ||
| + | |||
| + | {{ :t7670sa:t-7670sa-sim.jpg?direct&600 |}} | ||
| Once you have the nano SIM and LTE antenna connected, plug the USB-C cable from the board to your computer. The blue LED will turn on. | Once you have the nano SIM and LTE antenna connected, plug the USB-C cable from the board to your computer. The blue LED will turn on. | ||
| + | |||
| + | {{ :t7670sa:t-7670sa-antenna-leds.jpg?direct&600 |}} | ||
| Load up Putty. Connect to the active COM port and you'll get some of the following output. Feel free to press the reset button to see the entire startup output. For example: | Load up Putty. Connect to the active COM port and you'll get some of the following output. Feel free to press the reset button to see the entire startup output. For example: | ||
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| The 1 means that the network is registered, and is a home network. | The 1 means that the network is registered, and is a home network. | ||
| - | {{ :t7670sa:t-a7670sa-top-wired.jpg?direct&400 |}} | + | {{ :t7670sa:t-a7670sa-top-wired.jpg?direct&600 |}} |
| ===== Phonebook Entries ===== | ===== Phonebook Entries ===== | ||
| Line 101: | Line 105: | ||
| You can list out all the Phonebook entries stored on your SIM or search for a number using a string. | You can list out all the Phonebook entries stored on your SIM or search for a number using a string. | ||
| - | ********* list all | + | ''AT+CPBR=1,500'' will list all entries from 1 to 500 which, I believe, might be a SIM maximum. Even if you have less than 500, this will show all entries regardless. |
| AT+CPBR=2 | AT+CPBR=2 | ||
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| Take care with the connections. The pads are very small, especially the mic pair. After soldering the speaker and condenser mic, the following commands allow you to play with the mic gain and speaker volume: | Take care with the connections. The pads are very small, especially the mic pair. After soldering the speaker and condenser mic, the following commands allow you to play with the mic gain and speaker volume: | ||
| - | {{ :t7670sa:t-a7670sa-soldering.jpg?direct&400 |}} | + | {{ :t7670sa:t-a7670sa-soldering.jpg?direct&600 |}} |
| ''AT+CSDVC=3'' lets you set the mic gain to 3. | ''AT+CSDVC=3'' lets you set the mic gain to 3. | ||
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| ''AT+CHUP'' | ''AT+CHUP'' | ||
| - | And you get the "deact" messages as outlined in the last section. | + | And you get the "deact" messages as outlined in the previous section. |
| ===== What's next? ===== | ===== What's next? ===== | ||
| - | {{ :t7670sa:t-a7670sa-on-bench.jpg?direct&400 |}} | + | {{ :t7670sa:t-a7670sa-on-bench.jpg?direct&600 |}} |
| There's so much more you can do. Experiments in MQTT and HTTPS for example. I'll cover some in another article. You can also use ESP-IDF to examine the firmware and partitions of the flash memory. | There's so much more you can do. Experiments in MQTT and HTTPS for example. I'll cover some in another article. You can also use ESP-IDF to examine the firmware and partitions of the flash memory. | ||
build_your_own_mobile_phone.1738721895.txt.gz ยท Last modified: 2025/02/05 02:18 by sausage
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