Table of Contents
TimeHat Overview
Pi HAT (hardware attached on top) for timekeeping applications.
Architecture:
- GPS module with UART and PPS on 3v3 TTL
- Maxim DS3231SN RTC module on i2c
Version 0.01
Version 0.01 is what I already have made: COTS modules assembled on protoboard.
No additional modules will be built.
Version 0.1
The 0.1 version will be a custom PCB with COTS modules.
Fifteen modules will be built. (Maybe 20, I ordered 20 PCBs)
| Part | Link | # Ordered | Unit Cost | Bulk Cost | Misc | |
|---|---|---|---|---|---|---|
| uBlox MAX-M8Q w/ antenna | https://www.ebay.com/itm/264461410997 | $15.56 | $311.20 | $7.53 for GPS alone | ||
| DS3132 Module | https://www.amazon.com/gp/product/B082VL4GM6 | 20 | $1.78 | 35.96 | (5 for $8.99) | |
| CR2032 | https://www.amazon.com/gp/product/B008XBK7PG | 20 | $0.44 | $8.75 | (Pricing for 20) | |
| M3 6mm Screws | https://www.amazon.com/gp/product/B012TE12CY | 60 | $0.67 | $10.01 | Bought 60, boards need 4 | |
| M3 11mm Standoff | https://www.amazon.com/gp/product/B07D3Q9YDX | 100 | $0.39 | $9.69 | Bought 100, boards need 4 | |
| 2×20 Pin Female Header | https://www.amazon.com/gp/product/B07DNHS2SJ | 20 | $0.94 | $18.76 | ||
| PCBs | https://jlcpcb.com/order | 20 | $1.28 | $25.50 | ||
| Unit Cost | $21.06 | |||||
| Total Cost (15) | $419.87 |
Part notes:
DS3231SN module dimensions: 21mm wide, 38mm long
MAX-M8Q module dimensions: 24mm wide, 29mm long (SMA conn adds 10mm)
Board Design:
Version 1
The first “real” version will be a custom PCB with the GPS module and DS3231 mounted directly to it, no intermediary parts.