![\"\"](\"http:\/\/ainslies.net\/wp-content\/uploads\/2017\/02\/ChipTNC-1.jpg\")
<\/a>I’ve had a mobilinkd<\/a> for a couple of years now and I like the small form factor and the mobility of the device. I’ve always wanted it to have some additional features such as a connected mode ( either USB or serial ) and the ability to track without the need for a cell phone. Wifi would also be a preferred wireless interface.<\/p>\nI tried using the AP510 to fill some of these features but it’s under powered and prone to burning out it’s LDO.<\/p>\n
At the urging of a friend, Herb<\/a>, I sat down and designed one that fit our needs.<\/p>\n The hardware feature set we decided on<\/strong><\/p>\n For the ARM module we chose the C.H.I.P.<\/a> by Next Thing Co. I has a nice small form factor and the site claims you can order 1 – 1 million with very little lead time ( it turns out they are limiting you to 5 at a time right now ). A couple of other nice features of the module are WiFi, bluetooth, Lipo charger and 2 USB ports.<\/p>\n I used the same audio\/PTT interface as the mobilinkd so I could reuse the audio cables.<\/p>\n We chose the SR FRS 1W<\/a> for the on board RF interface. It’s got a nice small form factor but there are some issues with it’s PTT that we are still debugging.<\/p>\n The GPS expansion port is just a slot in the board with serial RX\/TX, i2c, 3V3, 5V and GND. I’ve looked at a few GPS modules but haven’t started designing anything yet. Part of the reason I’m holding off is that the side of the board I wanted to put the expansion on would interfere with the USB ports from the CHIP. Until I design a GPS interface module I’m just using a small ND-105 MicroUSB adapter<\/a>.<\/p>\n I chose the XBee header because there are a number of boards that are already designed for that form factor that support a large number of RF protocols. Now, because of the issues with the GPS expansion slot I might just design a GPS module to plug in there.<\/p>\n Running the audio interface and the GPS dongle from a 2500mAH battery the board can run for about 4 hours. I need to do some optimisation to try and get that into the 8 hours range.<\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n Software features<\/strong><\/p>\n The UI is written in python using the web.py framework and currently supports these features.<\/p>\n These all need cleaning up but for the most part are functional.<\/p>\n For the message interface a message daemon is needed to store messages for the interface and handle message ACKs. It attempts to re-transmit the message 3 times or until it is properly ACKed. The UI can also re-send failed messages.<\/p>\n I want to add a feature that failed messages will be re-transmitted when the messaged receives a beacon from the intended recipient.<\/p>\n Moving forward<\/strong><\/p>\n The boards arrived a week ago and apart from a few minor difficulties ( wrong parts, reversed RF module foot prints , you know the usual ) are working working well. So a second rev will be required. But a new rev means new features , right ?<\/p>\n The code is all hosted on gitlab right now in a private repo but I’ll probably open that up if there are any others interested in helping out.<\/p>\n","protected":false},"excerpt":{"rendered":" I’ve had a mobilinkd for a couple of years now and I like the small form factor and the mobility of the device. I’ve always wanted it to have some additional features such as a connected mode ( either … Continue reading \n
![\"\"](\"http:\/\/ainslies.net\/wp-content\/uploads\/2017\/02\/ChipTNC_PCB_front-1-174x300.jpg\")
<\/a><\/p>\n![\"\"](\"http:\/\/ainslies.net\/wp-content\/uploads\/2017\/02\/ChipTNC_PCB_back-1-173x300.jpg\")
<\/a><\/p>\n\n
![](\"http:\/\/ainslies.net\/wp-content\/uploads\/2017\/02\/ChipTNC_settings.png\")
<\/a> ![\"\"](\"http:\/\/ainslies.net\/wp-content\/uploads\/2017\/02\/ChipTNC_map-300x283.png\")
<\/a>I had to make some modifications to Direwolf to get it to handle multiple TCPIP clients, as APRX, the web ui and a message daemon all share Direwolf.<\/p>\n\n
\nREV2 features <\/strong><\/p>\n\n