Interfacing MCU, IMU, and mechanical devices - Page 1
Forum section: electronics / beginners

author: metrologist
author_rank: Super Contributor
timestamp: May 01, 2025, 03:54:22 pm
content: How does one typically interface these devices?ESP32 dev kit with pin pitch 2.54BMI088 shuttle board 3.0 with pin pitch 1.27Servos with female pin pitch 2.54GPS (TBD)Battery?I was thinking of a custom PCBway board with the correct size headers. I haven't done any of that though. Will they install the headers?Otherwise, I have wired connectors, glue, p-p soldered jumpers.Environment will experience moderate g and impulse forces.

author: Poroit
author_rank: Frequent Contributor
timestamp: May 03, 2025, 06:17:13 am
content: G'day metrologist,If it is a One Off project then your wired connectors, glue, p-p soldered jumpers should be sufficient.

author: metrologist
author_rank: Super Contributor
timestamp: May 03, 2025, 11:06:36 am
content: It's really for a kids school project. The IMU shuttle board with the small pin pitch is the hang. Can't easily breadboard that...I found the little 1.27 to 2.54 PCB pitch adapters. 5 for ten bucks for a limited time...I gave them a couple salvaged cables with 8-pin x 1.27 pitch headers on one side.Why does Bosch make this board with a 7- and 9-pin header with NC in the middle somewhere? Nobody sells these connectors.https://www.bosch-sensortec.com/media/boschsensortec/downloads/shuttle_board_flyer/application_board_3_1/bst-bmi088-sf000.pdfSo I just found on Ali various headers. My suggestion would be to route out a standard 2.54 pitch perf board and glue in this header, and p-p solder wires to ESP32 dev board headers.https://www.bosch-sensortec.com/media/boschsensortec/downloads/shuttle_board_flyer/application_board_3_1/bst-bmi088-sf000.pdf

author: Ian.M
author_rank: Super Contributor
timestamp: May 03, 2025, 01:50:04 pm
content: You can get through hole 1.27mm to 2.54mm pitch adapter boards*off the shelf. A pair of 10 way ones would let you break out the Shuttle board IMU to 0.1" pitch headers, although as the odds of it being an exact 0.1" multiple between the rows are small, it probably wouldn't be breadboard compatible, so you'd be using duPont jumper cables with it.Bosch use this odd-ball header layout because they do a carrier board for 'sensor evaluation' and (presumably) want to lock you in to their products, so aren't willing to use an open standard likemikroBUS.If you've got more than a couple of RC servos, power and ground distribution to them becomes problematic, even if your MCU has enough pins capable of Futaba RC servo PWM. If you also don't have enough pins capable of servo signals, something like Adafruit's16-Channel PCA9685 PWM/Servo driver boardbecomes rather attractive, as the servos plug straight into it.* e.g.https://www.chipquik.com/store/product_info.php?products_id=3800054

author: metrologist
author_rank: Super Contributor
timestamp: May 05, 2025, 12:02:29 pm
content: I had not considered the row spacing, but he'll solder pin headers onto perf board so we can bend the headers or make new holes where needed, or just connect to the perf board with wires. It would be nice to build it on a breadboard first.It's only 4 servos - using ESP32-S3-DevKitC-1

author: metrologist
author_rank: Super Contributor
timestamp: May 07, 2025, 04:26:30 am
content: I looked at the datasheet again for the shuttleboard. Other than the odd pin counts, the row spacing is a multiple of its pin pitch, but as suspected, the pitch adapter boards were not designed to properly adapt row spacing. Not quite in between, just a little too close.Now I was thinking I could simply bend the male header pins slightly. Top pins one way, bottom pins the other, ~11deg. That would slightly tilt the plastic block but seems inconsequential.

author: Ian.M
author_rank: Super Contributor
timestamp: May 07, 2025, 05:12:15 am
content: Dry fit it*and see how bad the tilt looks. If you don't like what you see, you could use a 0.1" pitch header one side and downwards bare wire links the other, that you can put a kink in after soldering to the adapter board. If the spacing discrepancy was worse, you could put the wire links in upwards, and bend them over like staples to go down the next clear row of holes beyond the adapter board edge.* i.e. don't solder.